Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil

*Lucia Morrone, Annalisa Rotondi, Francesca Rapparini and Gianpaolo Bertazza*

## **Abstract**

The extra virgin olive oil (EVOO) chemical and sensory characteristics depend on several factors such as the environment, the genetic matrix, stage of olive ripeness, phytosanitary conditions of olive, time and way of olive storage before transformation, and technological features of olive mill. In this chapter, the time of olive storage and two different types of extraction equipment are taken into account to deep understand their impact on chemical and sensory profile of EVOO. The knowledge of how these factors act will allow to manage the production chain adequately and to act on the various steps in order to improve the quality of EVOO. The sensory modifications of olive oils processed with two different types of extraction system during the storage were also evaluated.

**Keywords:** extra virgin olive oil, olive storage, oil extraction, Sinolea, decanter, sensory analysis, aroma analysis

## **1. Introduction**

Extra virgin olive oil (EVOO) quality is the result of the interaction of agronomic, pedoclimatic, and technological factors. Among all these factors, the olive fruit characteristics that entering the oil mill are a key factor and probably the most important variable involved in the quality of the final virgin olive oil [1].

The European low stated that EVOO is obtained exclusively through physical procedures as states in European regulation 1513/01 [2], of which the main technological steps are crushing, kneading, and malaxing the oil extraction. Olive oil is one of the few vegetable oils that can be consumed without refining, and so, this makes EVOO comparable to a fruit juice. In fact, EVOO contains phenols responsible for the bitter and pungent taste, and moreover, hydroxytyrosol, a phenolic alcohol, confers health properties as stated by EFSA [3].

In light of this, it is evident that the state of the raw material greatly affects the chemical and sensory characteristics of the EVOO. Moreover, the olive fruit characteristics interact with the technological features of olive mill resulting in different EVOO product's characteristics [4].

Postharvest period of a fruit comprises all the processes that the olive is subjected from harvesting to its industrial transformation. The degree of excellence of virgin olive oil is directly related to the physiological stage of the fruit when

processed, and this is the most important factor determining its level of quality [5]. The olive is formed by the epicarp or skin that is composed of 1.5–3.5% of the drupe weight, by the mesocarp or pulp that constitutes between 70 and 80%, by the endocarp or hazel that constitutes between 15 and 25%, and by the almond or seed that has a weight on the total between 2.5 and 4%. The mesocarp is made up mostly of water, oil, and carbohydrates. Triacylglycerols (TGs) are synthesized in plastids and mitochondria of the pulp cell cytoplasm, and then, they merge to produce small oil drops until they reach a diameter of 30 μn. These drops are stabilized by a polysaccharide membrane, unlike what happens in the oil seeds where the oil droplets are incorporated in the oleosomes [6]. The cell wall of the mesocarp cells is rigid and, together with the constituents of the cells, contributes to the firm consistency of the pulp that occurs at the beginning of maturation. During olive ripening, the cell walls become thinner, and the cells are gradually separated due to the solubilization of the pectins and hemicelluloses with consequent softening of the pulp. This phenomenon makes the olive a delicate fruit, whose handling must be done trying to avoid damaging the fruit. The storage of olives in pile, as is often done when there is no synchronization between collection and processing, produces a large heating and crushing of the fruits with a consequent loss of cellular fluids [7]. In these conditions, fruits mechanically damaged are extremely sensitive to fungi infection that leads and accelerates the hydrolytic and oxidative degeneration produced by lipases, lipoxygenases, and liases of both olive and parasitic origin [5]. Fermentative phenomena produce acetic and butyric acids, which cause off flavor in the oil and are responsible for the typical musty smell [7]. Oils produced from these olives have high values of acidity, number of peroxides, and high ultraviolet constants, often above the limits set by regulation 2568/1991 and following amendments that will make them lampante and therefore destined for refining because they are not suitable for human consumption [8]. To prevent this degeneration of the fruits and therefore to avoid obtaining oil with poor chemical and sensorial characteristics, the adoptable strategies are to reduce the storage times by better coordinating the phases of collection and transformation.

Several studies have been conducted to explore the possibility of storing olives in a refrigerated environment. It has been seen that oils obtained from olives stored at 5°C up to 30 days preserved the best characteristics compared to those obtained from olives kept at environment temperature [5, 8]. However, each cultivar can behave differently with respect to both cold storage and storage times [8].

In Emilia Romagna region, one of the northernmost areas in Italy for olive cultivation, the olive harvest phase is well synchronized with the olive mill; however, the olive production in this region is increasing, so a study on the behavior of the storage times of the autochthonous olive cultivars was undertaken. Moreover, a comparison of chemical and sensory characteristics of Nostrana di Brisighella EVOO produced by percolation method, namely Sinolea, and decanter technology was carried out.

## **2. Impact of the olive storage time on the chemical and sensory characteristics of the oils**

Olive oil samples (*n* = 132) were collected from seven different industrial oil mills located in Emilia Romagna region (Italy). In order to standardize the technological factor, only mills equipped with continuous systems, having hammer crusher, two phase decanters, centrifugation, and filtration phases. Only healthy olive samples without any kind of infection or physical damage were collected.

**31**

*a*

*b*

**Table 1.**

*oleic acid in 100 g of oil.*

*Analytical determination of olive oils.*

*mEq O2 kg−1 g of oil.*

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil*

Results reported in **Table 1** show the analytical determination carried out in accordance with the EU regulation 2568/91 and following amendments. Free acidity showed statistical significant differences only in oils obtained from cultivar mixture, while neither in Nostrana di Brisighella nor in Leccino, a trend was detectable. This indicates the importance of genetic matrix in the deterioration process of oils. The same behavior was shown by peroxide number: only in cultivar Nostrana di Brisighella, a statistical difference was detected. Peroxide number is an indicator of the primary oxidation with a legal limit for EVOO of 20 mEq O2/kg of oil. K232 and K270 are indexes primarily used to detect frauds, with the legal limits for EVOO of 2.5 for K232 and 0.2 for K270. K232 is also used as an indicator of olive oil primary oxidation, while K270 indicates secondary oxidation in EVOO. Values detected for K232 and K270 were below legal limit but do not discriminate oils according to the

Phenolic compounds are present in the water dispersion in EVOO. Phenols act as radical scavenging [9], lengthening the EVOO's shelf life. But the long storage times of the olives have led to an impoverishment of the phenolic content of the oils in all samples (**Table 2**). Olive of Nostrana di Brisighella and Leccino stored for 3–6 days showed a decrease in total phenol content and OSI, and a clear reduction trend in both OSI and total phenol content is detectable as the olive storage time proceeds. Olives stored for over 7 days have suffered a drastic breakdown of the phenol content in all oil samples. In particular, the Nostrana di Brisighella oils suffered a phenol loss up to about 76%. This latter cultivar undergoes the phenol degradation in a short time, and probably, its dual purpose attitude makes it delicate. This impoverishment in phenols also affects the stability of the oils. A clear reduction trend was detectable in OSI time in all samples even if in the Nostrana di Brisighella cultivar, the differences were statistically significant. These results agree with stud-

**Free aciditya Peroxid** 

NdB <48 h 0.30 ± 0.10 6.47 ± 2.15a 1.49 ± 0.58 0.09 ± 0.04

Mix <48 h 0.33 ± 0.14a 8.62 ± 2.83 1.57 ± 0.38 0.08 ± 0.03

Leccino <48 h 0.33 ± 0.12 7.33 ± 1.97 1.42 ± 0.10 0.06 ± 0.04

*The values reported are means ± standard deviation. NdB, Nostrana di Brisighella; Mix, varietal mixture. Different* 

*letters in the column indicate significant difference at 5% for each cultivar.*

**numberb**

3–6 days 0.27 ± 0.06 8.03 ± 2.96b 1.63 ± 0.7 0.08 ± 0.04 >7 days 0.28 ± 0.04 9.83 ± 2.35b 1.72 ± 0.26 0.08 ± 0.01 *p*-Value 0.840 0.046 0.135 0.541

3–6 days 0.50 ± 0.27b 8.53 ± 2.82 1.56 ± 0.45 0.09 ± 0.03 >7 days 0.53 ± 0.32b 9.81 ± 3.15 1.67 ± 0.57 0.09 ± 0.03 *p*-Value 0.001 0.145 0.152 0.563

3–6 days 0.37 ± 0.22 7.42 ± 2.96 1.53 ± 0.29 0.08 ± 0.02 >7 days 0.34 ± 0.1 12.07 ± 1.75 1.79 ± 0.07 0.07 ± 0.01 *p*-Value 0.939 0.097 0.223 0.531

**k232 k270**

*DOI: http://dx.doi.org/10.5772/intechopen.88888*

time of olive storage.

ies of Vichi and colleagues [10].

**Time of olive storage**

#### *Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil DOI: http://dx.doi.org/10.5772/intechopen.88888*

Results reported in **Table 1** show the analytical determination carried out in accordance with the EU regulation 2568/91 and following amendments. Free acidity showed statistical significant differences only in oils obtained from cultivar mixture, while neither in Nostrana di Brisighella nor in Leccino, a trend was detectable. This indicates the importance of genetic matrix in the deterioration process of oils. The same behavior was shown by peroxide number: only in cultivar Nostrana di Brisighella, a statistical difference was detected. Peroxide number is an indicator of the primary oxidation with a legal limit for EVOO of 20 mEq O2/kg of oil. K232 and K270 are indexes primarily used to detect frauds, with the legal limits for EVOO of 2.5 for K232 and 0.2 for K270. K232 is also used as an indicator of olive oil primary oxidation, while K270 indicates secondary oxidation in EVOO. Values detected for K232 and K270 were below legal limit but do not discriminate oils according to the time of olive storage.

Phenolic compounds are present in the water dispersion in EVOO. Phenols act as radical scavenging [9], lengthening the EVOO's shelf life. But the long storage times of the olives have led to an impoverishment of the phenolic content of the oils in all samples (**Table 2**). Olive of Nostrana di Brisighella and Leccino stored for 3–6 days showed a decrease in total phenol content and OSI, and a clear reduction trend in both OSI and total phenol content is detectable as the olive storage time proceeds. Olives stored for over 7 days have suffered a drastic breakdown of the phenol content in all oil samples. In particular, the Nostrana di Brisighella oils suffered a phenol loss up to about 76%. This latter cultivar undergoes the phenol degradation in a short time, and probably, its dual purpose attitude makes it delicate. This impoverishment in phenols also affects the stability of the oils. A clear reduction trend was detectable in OSI time in all samples even if in the Nostrana di Brisighella cultivar, the differences were statistically significant. These results agree with studies of Vichi and colleagues [10].


*The values reported are means ± standard deviation. NdB, Nostrana di Brisighella; Mix, varietal mixture. Different letters in the column indicate significant difference at 5% for each cultivar.*

*a oleic acid in 100 g of oil.*

*b mEq O2 kg−1 g of oil.*

#### **Table 1.**

*Analytical determination of olive oils.*

*Food Processing*

phases of collection and transformation.

processed, and this is the most important factor determining its level of quality [5]. The olive is formed by the epicarp or skin that is composed of 1.5–3.5% of the drupe weight, by the mesocarp or pulp that constitutes between 70 and 80%, by the endocarp or hazel that constitutes between 15 and 25%, and by the almond or seed that has a weight on the total between 2.5 and 4%. The mesocarp is made up mostly of water, oil, and carbohydrates. Triacylglycerols (TGs) are synthesized in plastids and mitochondria of the pulp cell cytoplasm, and then, they merge to produce small oil drops until they reach a diameter of 30 μn. These drops are stabilized by a polysaccharide membrane, unlike what happens in the oil seeds where the oil droplets are incorporated in the oleosomes [6]. The cell wall of the mesocarp cells is rigid and, together with the constituents of the cells, contributes to the firm consistency of the pulp that occurs at the beginning of maturation. During olive ripening, the cell walls become thinner, and the cells are gradually separated due to the solubilization of the pectins and hemicelluloses with consequent softening of the pulp. This phenomenon makes the olive a delicate fruit, whose handling must be done trying to avoid damaging the fruit. The storage of olives in pile, as is often done when there is no synchronization between collection and processing, produces a large heating and crushing of the fruits with a consequent loss of cellular fluids [7]. In these conditions, fruits mechanically damaged are extremely sensitive to fungi infection that leads and accelerates the hydrolytic and oxidative degeneration produced by lipases, lipoxygenases, and liases of both olive and parasitic origin [5]. Fermentative phenomena produce acetic and butyric acids, which cause off flavor in the oil and are responsible for the typical musty smell [7]. Oils produced from these olives have high values of acidity, number of peroxides, and high ultraviolet constants, often above the limits set by regulation 2568/1991 and following amendments that will make them lampante and therefore destined for refining because they are not suitable for human consumption [8]. To prevent this degeneration of the fruits and therefore to avoid obtaining oil with poor chemical and sensorial characteristics, the adoptable strategies are to reduce the storage times by better coordinating the

Several studies have been conducted to explore the possibility of storing olives in a refrigerated environment. It has been seen that oils obtained from olives stored at 5°C up to 30 days preserved the best characteristics compared to those obtained from olives kept at environment temperature [5, 8]. However, each cultivar can behave differently with respect to both cold storage and storage times [8]. In Emilia Romagna region, one of the northernmost areas in Italy for olive cultivation, the olive harvest phase is well synchronized with the olive mill; however, the olive production in this region is increasing, so a study on the behavior of the storage times of the autochthonous olive cultivars was undertaken. Moreover, a comparison of chemical and sensory characteristics of Nostrana di Brisighella EVOO produced by percolation method, namely Sinolea, and decanter technology

**2. Impact of the olive storage time on the chemical and sensory** 

Olive oil samples (*n* = 132) were collected from seven different industrial oil mills located in Emilia Romagna region (Italy). In order to standardize the technological factor, only mills equipped with continuous systems, having hammer crusher, two phase decanters, centrifugation, and filtration phases. Only healthy olive samples without any kind of infection or physical damage were collected.

**30**

was carried out.

**characteristics of the oils**


*The values reported are means ± standard deviation. NdB, Nostrana di Brisighella; Mix, varietal mixture OSI, Oxidative stability index. Different letters in the same column indicate significant difference at 5% for each cultivar.* a *hours.* b *mg of gallic acid kg−1 of oil.*

## **Table 2.**

*Total phenols content and OSI time detected in olive.*

The sensory profile that characterizes an oil is the result of the interaction of numerous substances, both volatile and non-volatile, which stimulate specific receptors allowing us to discriminate the different flavors and smells of olive oil. The oil sensory characteristics are influenced by several factors linked both to the raw material: variety, stage of maturation of the olives, and time and storage conditions and to the extraction technology during which enzymatic reactions take place allowing the formation of aromas [1].

Sensory analysis was performed by the "ASSAM—Marche panel," a fully trained taste panel recognized by the International Olive Oil Council (IOOC) of Madrid, Spain, and by the Ministry for Agriculture, Food, and Forestry Policy.

The sensory profiles of Nostrana di Brisighella olive oil show differences between oils from olive milled within 48 h and after 48 h. In particular, from **Figure 1**, it is possible to see that there is a statistically significant decrease in olive fruity intensity, grass, pungent, and other pleasant notes in oil from olive processed after 48 h. The same trend is detectable in oils from cv. Leccino, of which the radar chart is shown in **Figure 1**. Oils of cv. Leccino milled after the harvest show higher values of all sensory descriptors than oils milled after several days after the harvest. For the cultivar mixtures, influence of the time of storage of the olives was found (**Figure 1**). In fact, differences in olive fruity, grass, bitter, and pungent sensory descriptor were detectable.

However, it is important to underline that in the oil samples with more than 48 h of olive storage time, the percentage of oils with sensory defects was always greater than the oils of the same cultivar with shorter storage time.

With the aim of evaluating the shelf life of the olive oils, the sensory analyses were repeated after 1 year. The EVOO shelf life is a delicate phase since an impoverishment of sensory and chemical characteristics can occur. During the shelf life, oxidation process takes place, and it is characterized by two phases: in the first phase, the oxygen reacts with the unsaturated fatty acids forming hydroperoxides,

**33**

**Figure 1.**

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil*

*Sensory profiles of Nostrana di Brisighella, varietal mix, and Leccino processed at different olive storage times* 

*(<48 h and >48 h). The asterisks indicate statistical significance at 5% level.*

*DOI: http://dx.doi.org/10.5772/intechopen.88888*

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil DOI: http://dx.doi.org/10.5772/intechopen.88888*

**Figure 1.**

*Food Processing*

a *hours.* b

**Table 2.**

*mg of gallic acid kg−1 of oil.*

The sensory profile that characterizes an oil is the result of the interaction of numerous substances, both volatile and non-volatile, which stimulate specific receptors allowing us to discriminate the different flavors and smells of olive oil. The oil sensory characteristics are influenced by several factors linked both to the raw material: variety, stage of maturation of the olives, and time and storage conditions and to the extraction technology during which enzymatic reactions take place

**Time of olive storage OSIa Total phenolsb**

3–6 days 28.06 ± 6.99a,b 203.1 ± 123.77a,b >7 days 15.1 ± 5.37<sup>b</sup> 63.4 ± 23.09b *p*-Value 0.020 0.007

3–6 days 20.45 ± 7.81 189.3 ± 86.92 >7 days 19.08 ± 10.07 150.4 ± 68.65 *p*-Value 0.092 0.137

3–6 days 19.69 ± 6.69 153.93 ± 78.72 >7 days 19.43 ± 9.02 108.29 ± 72.41 *p*-Value 0.219 0.209

NdB <48 h 33.28 ± 9.68a 265.31 ± 90.07a

Mix <48 h 23.31 ± 7.93 185.13 ± 79.7

Leccino <48 h 31.21 ± 20.15 251.06 ± 170.76

*The values reported are means ± standard deviation. NdB, Nostrana di Brisighella; Mix, varietal mixture OSI, Oxidative stability index. Different letters in the same column indicate significant difference at 5% for each cultivar.*

Sensory analysis was performed by the "ASSAM—Marche panel," a fully trained taste panel recognized by the International Olive Oil Council (IOOC) of Madrid,

However, it is important to underline that in the oil samples with more than 48 h of olive storage time, the percentage of oils with sensory defects was always greater

With the aim of evaluating the shelf life of the olive oils, the sensory analyses were repeated after 1 year. The EVOO shelf life is a delicate phase since an impoverishment of sensory and chemical characteristics can occur. During the shelf life, oxidation process takes place, and it is characterized by two phases: in the first phase, the oxygen reacts with the unsaturated fatty acids forming hydroperoxides,

Spain, and by the Ministry for Agriculture, Food, and Forestry Policy.

than the oils of the same cultivar with shorter storage time.

The sensory profiles of Nostrana di Brisighella olive oil show differences between oils from olive milled within 48 h and after 48 h. In particular, from **Figure 1**, it is possible to see that there is a statistically significant decrease in olive fruity intensity, grass, pungent, and other pleasant notes in oil from olive processed after 48 h. The same trend is detectable in oils from cv. Leccino, of which the radar chart is shown in **Figure 1**. Oils of cv. Leccino milled after the harvest show higher values of all sensory descriptors than oils milled after several days after the harvest. For the cultivar mixtures, influence of the time of storage of the olives was found (**Figure 1**). In fact, differences in olive fruity, grass, bitter, and pungent sensory

allowing the formation of aromas [1].

*Total phenols content and OSI time detected in olive.*

descriptor were detectable.

**32**

*Sensory profiles of Nostrana di Brisighella, varietal mix, and Leccino processed at different olive storage times (<48 h and >48 h). The asterisks indicate statistical significance at 5% level.*

**Figure 2.**

*Sensory profiles of Nostrana di Brisighella, Leccino, and varietal mix after 12 months from oil production (T12).*

**35**

*at 5%. 1*

**Table 3.**

*2*

*g Oleic acid in 100 g oil.*

*Peroxide value, mEq O2 kg−1 of oil.*

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil*

48 h maintained their sensory profile over the conservation.

oils extracted using this method were less oxidized.

Sinolea than the oils extracted using Decanter.

*Quality indices of virgin olive oil extracted using Sinolea and decanter systems.*

**3. Sinolea and decanter: comparison of two extracting methods**

The oil extracting method deeply influences the chemical and sensory characteristics of olive oil [4]. In this section, we compare the chemical and sensory characteristics of olive oils obtained using the Sinolea and decanter continuous methods. The Sinolea method exploits the different surface tension of the vegetation water and the oil, and these different physical behaviors allow the olive oil to adhere to a steel plaque, while the other two phases remain behind. It is made up of several metal plates that are dipped into the paste: the oil preferentially wets and sticks to the metal and is removed with scrapers in a continuous process. The decanter centrifugation method exploits centrifugal force allowing the separation of the phases according to their different densities. The study was carried out on the cv. Nostrana di Brisighella. The samples analyzed did not show a significant difference in free acidity and K270, while the peroxide number and K232 revealed differences in the two systems studied (**Table 3**). The peroxide number and K232 give us information about the primary lipid oxidation, so these data suggest a different impact on lipid oxidation of the two extraction methods used. In particular, the Sinolea seems to be more "gentle," and

Tocopherols are lipid soluble vitamins and act as antioxidants by maintaining the cell membrane stability and by preventing the oxidative damage of tissues [11]. Alfa tocopherol has a synergistic effect on ortho-diphenols and contributes significantly to the retardation of peroxide formation [12]. As far as concern the antioxidant substance, the results are presented in **Table 4**. The content of alfa tocopherol was greater in samples extracted with Sinolea than the content of olive oils extracted using decanter. Also, the total phenolic content and the oil stability were greater in oils extracted with Sinolea system. A correlation was found between OSI and phenol content [13], and so, the OSI time is greater in oils extracted using

**Free acidity1 Peroxide number2 k232 k270**

Sinolea 0.28 ± 0.07 5.67 ± 1.36 1.38 ± 0.58 0.08 ± 0.04 Decanter 0.30 ± 0.11 7.16 ± 2.49 1.56 ± 0.59 0.09 ± 0.03 *p*-Value 0.392 0.027 0.008 0.488 *Data are presented as mean ± standard deviation. Different letters in the same column indicate significant difference* 

which, being unstable, fragment itself and give rise to the second oxidation phase that finishes with the formation of ketones and aldehydes. From the radar chart in **Figure 2**, it is possible to see the influence of the olive storage time on the sensory characteristic of oils. In fact, oils produced from olive stored for more than 48 h showed a poor sensory profile compared to olive stored within 48 h. Furthermore, from the comparison of the T12 profiles with those taken just after pressing (**Figure 1**), it is possible to see the greater sensorial degradation of the oils crushed by olives stored for a long time. It is important to underline that oil processed within

*DOI: http://dx.doi.org/10.5772/intechopen.88888*

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil DOI: http://dx.doi.org/10.5772/intechopen.88888*

which, being unstable, fragment itself and give rise to the second oxidation phase that finishes with the formation of ketones and aldehydes. From the radar chart in **Figure 2**, it is possible to see the influence of the olive storage time on the sensory characteristic of oils. In fact, oils produced from olive stored for more than 48 h showed a poor sensory profile compared to olive stored within 48 h. Furthermore, from the comparison of the T12 profiles with those taken just after pressing (**Figure 1**), it is possible to see the greater sensorial degradation of the oils crushed by olives stored for a long time. It is important to underline that oil processed within 48 h maintained their sensory profile over the conservation.

## **3. Sinolea and decanter: comparison of two extracting methods**

The oil extracting method deeply influences the chemical and sensory characteristics of olive oil [4]. In this section, we compare the chemical and sensory characteristics of olive oils obtained using the Sinolea and decanter continuous methods. The Sinolea method exploits the different surface tension of the vegetation water and the oil, and these different physical behaviors allow the olive oil to adhere to a steel plaque, while the other two phases remain behind. It is made up of several metal plates that are dipped into the paste: the oil preferentially wets and sticks to the metal and is removed with scrapers in a continuous process. The decanter centrifugation method exploits centrifugal force allowing the separation of the phases according to their different densities. The study was carried out on the cv. Nostrana di Brisighella. The samples analyzed did not show a significant difference in free acidity and K270, while the peroxide number and K232 revealed differences in the two systems studied (**Table 3**). The peroxide number and K232 give us information about the primary lipid oxidation, so these data suggest a different impact on lipid oxidation of the two extraction methods used. In particular, the Sinolea seems to be more "gentle," and oils extracted using this method were less oxidized.

Tocopherols are lipid soluble vitamins and act as antioxidants by maintaining the cell membrane stability and by preventing the oxidative damage of tissues [11]. Alfa tocopherol has a synergistic effect on ortho-diphenols and contributes significantly to the retardation of peroxide formation [12]. As far as concern the antioxidant substance, the results are presented in **Table 4**. The content of alfa tocopherol was greater in samples extracted with Sinolea than the content of olive oils extracted using decanter. Also, the total phenolic content and the oil stability were greater in oils extracted with Sinolea system. A correlation was found between OSI and phenol content [13], and so, the OSI time is greater in oils extracted using Sinolea than the oils extracted using Decanter.


*Data are presented as mean ± standard deviation. Different letters in the same column indicate significant difference at 5%.*

*1 g Oleic acid in 100 g oil.*

*2 Peroxide value, mEq O2 kg−1 of oil.*

#### **Table 3.**

*Food Processing*

**34**

**Figure 2.**

*(T12).*

*Sensory profiles of Nostrana di Brisighella, Leccino, and varietal mix after 12 months from oil production* 

*Quality indices of virgin olive oil extracted using Sinolea and decanter systems.*


*Data are presented as mean ± standard deviation. Tocopherol is expressed as mg kg−1 of relative standard; OSI is expressed in hours; total phenols are expressed as mg of gallic acid kg−1 of oil. Different letters in the same column indicate significant difference at 5%.*

#### **Table 4.**

*Antioxidant fraction of virgin olive oil extracted by two methods: Sinolea and decanter.*

The results of sensory analysis of EVOO samples extracted using the Sinolea and decanter systems are shown in **Figure 3**. Oil extracted using Sinolea method presents higher intensities in olive fruity and grass scent than oil extracted using decanter extraction system. These results are in agreement with those of [14] who reported a higher panel score for EVOO extracted using Sinolea than EVOO extracted using decanter.

The sensory analysis was repeated after 12 months in order to verify if the sensory differences detected soon after the EVOO extractions were still present. The result of the sensory analysis carried out after 12 months is shown in **Figure 4**. EVOO extracted using Sinolea had still higher intensities of olive fruity and grass note after 12 months.

It is well known that the production of volatile compounds is a complex process starting when fruit tissues are broken, and enzymes and substrates come into contact [15]. Aside from olive cultivar, geographical origin, fruit ripening degree, and storage conditions, the aroma profile is affected during the fruit processing and oil extraction [16]. We investigated the effect of olive fruit processing and oil extraction using the Sinolea and decanter extraction systems on the volatile content of EVOO of Nostrana di Brisighella cultivar (**Tables 5–7**). The volatile compounds were extracted by dynamic headspace concentration on carbon traps and analyzed by gas chromatography and mass spectrometry. The sampling methodology and the instrument's working parameters for the detection, identification, and quantification of volatiles, were adjusted using the analysis method reported by Rapparini and Rotondi [17] and Vitalini [18]. Briefly, olive oil was extracted with pure He at a rate of 100 ml min−1 for 10 min (**Figure 5**).

The headspace volatiles released from 40 ml of oil were collected onto charcoal adsorbent traps (Carbotrap—0.17 g and Carbotrap C—0.034 g; Lara, Rome, Italy). The analytical system consists of a thermal desorber (Chrompack, Middleburg, The Netherlands) connected to a gas chromatograph GC (Hewlett Packard 5890) and a 5970 quadrupole mass spectrometer (MS) as detection system (Hewlett Packard, Palo Alto, CA, USA). All separations are performed on a 60 m × 0.25 mm I.D. capillary column (Hewlett Packard) coated with a 0.25-μm film of polymethylsiloxane. The temperature program was isothermal at 40°C for 7 min and increased to 240°C at 5°C min−1. Identification of the detected compounds is achieved by comparing the retention times, mass spectra of authentic standards (Fluka, Switzerland), and published literature spectra. Quantification of the volatiles was performed when standards were available as previously reported [18]. The individual compound concentrations were calculated by dividing the amount of the volatiles trapped onto the traps by the total sampled air volume and by the total volume of olive oil (ng ml−1).

The combination of dynamic headspace sampling and pre-concentration system with GC-MS analytical technique allowed us to determine in the volatile fraction of

**37**

employed.

**Figure 4.**

**Figure 3.**

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil*

olive oil samples, a total of 47 compounds (**Table 5**) mainly corresponding to the following chemical classes: alkanes, alcohols, aldehydes, ketones, and esters.

*Spider chart of sensory intensities indicates from panel test carried out after 12 months of EVOO storage (T12). The asterisk near the sensory attribute indicates a statistical significance difference (Tukey's test; \*p < 0.05).*

*Radar chart of sensory intensities indicates from panel test carried out soon after the EVOO production (T0). The asterisk near the sensory attribute indicates a statistical significance difference (Tukey's test; \*p < 0.05).*

The quantified volatiles are released at a wide range of concentration (from few ng ml−1 up to 1911 ng ml−1 of oil; **Table 5**). Overall, the total volatile content was higher in olive oil samples of second harvesting campaign (ranging from about 900 to 2500–4000 ng ml−1) than in olive oils obtained during the first campaign (ranging from 200 to 500 ng ml−1 of oil), independently of the extraction process

Among the different identified chemical classes, the six-carbon compounds, aldehydes, and alcohols, which have been related to fresh green odor, are especially abundant (**Table 6**). These compounds are produced during the oil extraction by the so-called lipoxygenase (LOX) pathway and activated by the mechanical break of olive fruit [19, 20]. The contribution of the total C6 volatile compounds in the analyzed oils is relevant, representing on average 50% of the total volatiles and reaching a maximum of ca. 72% of the total volatiles in the aroma profile of the oils obtained using the decanter system during the first harvesting campaign (**Table 6**).

*DOI: http://dx.doi.org/10.5772/intechopen.88888*

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil DOI: http://dx.doi.org/10.5772/intechopen.88888*

#### **Figure 3.**

*Food Processing*

**Table 4.**

extracted using decanter.

*indicate significant difference at 5%.*

note after 12 months.

rate of 100 ml min−1 for 10 min (**Figure 5**).

The results of sensory analysis of EVOO samples extracted using the Sinolea and decanter systems are shown in **Figure 3**. Oil extracted using Sinolea method presents higher intensities in olive fruity and grass scent than oil extracted using decanter extraction system. These results are in agreement with those of [14] who reported a higher panel score for EVOO extracted using Sinolea than EVOO

*Antioxidant fraction of virgin olive oil extracted by two methods: Sinolea and decanter.*

Sinolea 204.97 ± 20.93a 8.5 ± 0.95 34.82 ± 9.23 279.61 ± 66.18 Decanter 185.45 ± 32.23b 8.69 ± 1.47 31.08 ± 10.09 241.37 ± 108.92 *p*-Value 0.029 0.629 0.203 0.195 *Data are presented as mean ± standard deviation. Tocopherol is expressed as mg kg−1 of relative standard; OSI is expressed in hours; total phenols are expressed as mg of gallic acid kg−1 of oil. Different letters in the same column* 

**Α tocopherol β + γ tocopherols OSI Total phenol**

The sensory analysis was repeated after 12 months in order to verify if the sensory differences detected soon after the EVOO extractions were still present. The result of the sensory analysis carried out after 12 months is shown in **Figure 4**. EVOO extracted using Sinolea had still higher intensities of olive fruity and grass

It is well known that the production of volatile compounds is a complex process

The headspace volatiles released from 40 ml of oil were collected onto charcoal adsorbent traps (Carbotrap—0.17 g and Carbotrap C—0.034 g; Lara, Rome, Italy). The analytical system consists of a thermal desorber (Chrompack, Middleburg, The Netherlands) connected to a gas chromatograph GC (Hewlett Packard 5890) and a 5970 quadrupole mass spectrometer (MS) as detection system (Hewlett Packard, Palo Alto, CA, USA). All separations are performed on a 60 m × 0.25 mm I.D. capillary column (Hewlett Packard) coated with a 0.25-μm film of polymethylsiloxane. The temperature program was isothermal at 40°C for 7 min and increased to 240°C at 5°C min−1. Identification of the detected compounds is achieved by comparing the retention times, mass spectra of authentic standards (Fluka, Switzerland), and published literature spectra. Quantification of the volatiles was performed when standards were available as previously reported [18]. The individual compound concentrations were calculated by dividing the amount of the volatiles trapped onto the traps by the total sampled air volume and by the total volume of olive oil

The combination of dynamic headspace sampling and pre-concentration system with GC-MS analytical technique allowed us to determine in the volatile fraction of

starting when fruit tissues are broken, and enzymes and substrates come into contact [15]. Aside from olive cultivar, geographical origin, fruit ripening degree, and storage conditions, the aroma profile is affected during the fruit processing and oil extraction [16]. We investigated the effect of olive fruit processing and oil extraction using the Sinolea and decanter extraction systems on the volatile content of EVOO of Nostrana di Brisighella cultivar (**Tables 5–7**). The volatile compounds were extracted by dynamic headspace concentration on carbon traps and analyzed by gas chromatography and mass spectrometry. The sampling methodology and the instrument's working parameters for the detection, identification, and quantification of volatiles, were adjusted using the analysis method reported by Rapparini and Rotondi [17] and Vitalini [18]. Briefly, olive oil was extracted with pure He at a

**36**

(ng ml−1).

*Radar chart of sensory intensities indicates from panel test carried out soon after the EVOO production (T0). The asterisk near the sensory attribute indicates a statistical significance difference (Tukey's test; \*p < 0.05).*

#### **Figure 4.**

*Spider chart of sensory intensities indicates from panel test carried out after 12 months of EVOO storage (T12). The asterisk near the sensory attribute indicates a statistical significance difference (Tukey's test; \*p < 0.05).*

olive oil samples, a total of 47 compounds (**Table 5**) mainly corresponding to the following chemical classes: alkanes, alcohols, aldehydes, ketones, and esters.

The quantified volatiles are released at a wide range of concentration (from few ng ml−1 up to 1911 ng ml−1 of oil; **Table 5**). Overall, the total volatile content was higher in olive oil samples of second harvesting campaign (ranging from about 900 to 2500–4000 ng ml−1) than in olive oils obtained during the first campaign (ranging from 200 to 500 ng ml−1 of oil), independently of the extraction process employed.

Among the different identified chemical classes, the six-carbon compounds, aldehydes, and alcohols, which have been related to fresh green odor, are especially abundant (**Table 6**). These compounds are produced during the oil extraction by the so-called lipoxygenase (LOX) pathway and activated by the mechanical break of olive fruit [19, 20]. The contribution of the total C6 volatile compounds in the analyzed oils is relevant, representing on average 50% of the total volatiles and reaching a maximum of ca. 72% of the total volatiles in the aroma profile of the oils obtained using the decanter system during the first harvesting campaign (**Table 6**).


**39**

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil*

Aldehydes are the main fraction of the C6 volatiles, representing about 80–90% of the total C6 compounds from LOX pathway, while C6 alcohols contribute for about

*Volatile compounds detected in the headspace of EVOO of Nostrana di Brisighella cultivar sampled.*

characterized by green, fruity, and almond notes, was the main contributor (72–

[21]. The percentage of the sum of C6 volatiles derived from linolenic acid (LnA) on the total C6 compounds (ca. 83–89%) is in all samples higher than the sum of C6

previous results on EVOO oils [22]. Other C5 aromatic compounds, mainly ketones (ca. 20–45%) and alcohols (ca. 10%), contribute to the overall aroma profile of

volatiles were the major components of the C5 fraction, with 1-penten-3-one and 1-penten-3-ol being the most abundant volatiles among the C5 ketones and C5

Despite the differences in the absolute concentrations of the volatiles of the EVOO oils obtained during the two different harvesting campaigns, the relative contribution of volatile compounds, which has an high impact on oil sensory qual

In particular, when analyzing the volatile composition based on their origin from the LOX pathway, the percentage of the sum of C6 saturated aldehydes and alcohols (i.e., volatiles derived from the LA) results higher in the oils obtained using the Sinolea system (about 15–17% of the total C6 volatiles) than the aroma profile of volatiles from LA of oils extracted using the decanter system

system is characterized by a higher percentage of the C6 unsaturated volatiles (i.e., volatiles derived from the LnA; 89% of the total C6 volatiles), essentially due to the higher contribution of (E)-2-hexenal, than the relative content of these compounds in the oils from Sinolea (83–85%). Indeed, this volatile was found in greater proportion in the aroma profile of the oil extracted using the decanter system (80% of the total C6 compounds) than in those derived from the Sinolea

Taking into account that alterations of the relative concentrations of volatiles can have a significant impact on the sensorial characteristics of the oil [19, 20], the observed differences, even minor, evidence an impact of the extraction process on the enzymatic production of C5 and C6 volatiles from the LOX pathway, although physicochemical transformations cannot be excluded to be differentially induced by

the two employed technological procedure of oil extraction of this cultivar.

**7**). The aroma profile of the oils obtained using the decanter

compounds derived from linoleic acid (LA; 12–17%; **Table**

ity, is slightly different depending on the oil extraction system.

**7**). Among the C6 aldehydes, (E)-2-hexenal, which is generally

2-pentanone

3-pentanone

2-methyl butyl propanoate

Methyl benzoate

**7**) as usually found for the profile of EVOO

2-eptanone tr 6-methyl-5-epten-2-one tr

**5**). As with C6 compounds, LnA-derived C5

**7**), in accordance with

X

X

X

X

X


*DOI: http://dx.doi.org/10.5772/intechopen.88888*

**Classes Compounds**

Esters Ethyl acetate

10–13% (**Table**

**Table 5.**

*tr = traces (<0.01 ng/ml of oil).*

81%) of the total C6 volatiles (**Table**

Nostrana di Brisighella oils (**Table**

alcohol, respectively.

(ca. 11–12%; **Table**

one (about 72–75%).

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil DOI: http://dx.doi.org/10.5772/intechopen.88888*


#### **Table 5.**

*Food Processing*

**Classes Compounds**

Alkanes Methyl pentane X

Alcohols Ethanol X

Aldehydes 2-methyl propanal X

Ketones 2-Butanone X

Heptane X Octane X

1-propanol X 2-butanol X 2-methyl-1-propanol X 1-butanol X 1-penten-3-ol X 3-pentanol X (E)-2-penten-1-ol X (Z)-2-penten-1-ol X 3-methyl-1-butanol X 2-methyl-1-butanol X (E)-3-hexenol X (Z)-3-hexenol X (E)-2-hexenol X 1-hexanol X

Butanal X 2-butenal tr 3-methyl-butanal X 2-methyl-butanal X 2-methyl-2-butenal X Pentanal X (Z)-2-pentenal X (E)-2-Pentenal X (Z)-3-hexsenal X 1-hexanal X (E)-2-hexenal X Benzaldehyde tr Octanal X Nonanal X Ethyl-benzaldehyde X 2-nonenal X Decanal X 2-Decenal X (E)-2-decenal X

1-penten-3-one X

**38**

*Volatile compounds detected in the headspace of EVOO of Nostrana di Brisighella cultivar sampled.*

Aldehydes are the main fraction of the C6 volatiles, representing about 80–90% of the total C6 compounds from LOX pathway, while C6 alcohols contribute for about 10–13% (**Table 7**). Among the C6 aldehydes, (E)-2-hexenal, which is generally characterized by green, fruity, and almond notes, was the main contributor (72– 81%) of the total C6 volatiles (**Table 7**) as usually found for the profile of EVOO [21]. The percentage of the sum of C6 volatiles derived from linolenic acid (LnA) on the total C6 compounds (ca. 83–89%) is in all samples higher than the sum of C6 compounds derived from linoleic acid (LA; 12–17%; **Table 7**), in accordance with previous results on EVOO oils [22]. Other C5 aromatic compounds, mainly ketones (ca. 20–45%) and alcohols (ca. 10%), contribute to the overall aroma profile of Nostrana di Brisighella oils (**Table 5**). As with C6 compounds, LnA-derived C5 volatiles were the major components of the C5 fraction, with 1-penten-3-one and 1-penten-3-ol being the most abundant volatiles among the C5 ketones and C5 alcohol, respectively.

Despite the differences in the absolute concentrations of the volatiles of the EVOO oils obtained during the two different harvesting campaigns, the relative contribution of volatile compounds, which has an high impact on oil sensory quality, is slightly different depending on the oil extraction system.

In particular, when analyzing the volatile composition based on their origin from the LOX pathway, the percentage of the sum of C6 saturated aldehydes and alcohols (i.e., volatiles derived from the LA) results higher in the oils obtained using the Sinolea system (about 15–17% of the total C6 volatiles) than the aroma profile of volatiles from LA of oils extracted using the decanter system (ca. 11–12%; **Table 7**). The aroma profile of the oils obtained using the decanter system is characterized by a higher percentage of the C6 unsaturated volatiles (i.e., volatiles derived from the LnA; 89% of the total C6 volatiles), essentially due to the higher contribution of (E)-2-hexenal, than the relative content of these compounds in the oils from Sinolea (83–85%). Indeed, this volatile was found in greater proportion in the aroma profile of the oil extracted using the decanter system (80% of the total C6 compounds) than in those derived from the Sinolea one (about 72–75%).

Taking into account that alterations of the relative concentrations of volatiles can have a significant impact on the sensorial characteristics of the oil [19, 20], the observed differences, even minor, evidence an impact of the extraction process on the enzymatic production of C5 and C6 volatiles from the LOX pathway, although physicochemical transformations cannot be excluded to be differentially induced by the two employed technological procedure of oil extraction of this cultivar.


*Data are expressed as ng ml−1 of oil (mean ± standard error). Percentage of the different chemical compound and class relative to the total amount of volatiles is also shown.*

#### **Table 6.**

*Volatile compounds detected in the headspace of the olive oils obtained from Nostrana di Brisighella cultivar and extracted using a decanter or a Sinolea processing system.*

**41**

obtained oils.

**Figure 5.**

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil*

**%Compound/sum of C6 compounds 1st year 2nd year 1st year 2nd year** (*E*)-2-hexenal 80 81 72 76 3-hexen-1-ol 6 5 9 8 2-hexen-1-ol 2 3 2 1 Hexanal 9 9 15 14 Hexanol 2 2 3 1 **C6 aldehydes** 89 90 87 89 **C6 alcohols** 11 10 13 11 **Total C6 from LA** 12 11 17 15 **Total C6 from LnA** 89 89 83 85 *The percentage of the sum of C6 volatiles derived from linolenic acid (LnA) and from the linoleic acid (LA) on the* 

*Percent distribution of the C6 volatile compounds on the total amount of C6 compounds detected in the headspace of the olive oils obtained from Nostrana di Brisighella cultivar and extracted using a decanter or a* 

**Decanter Sinolea**

Although, previous studies on different olive cultivars, including Italian varieties, evidence that aroma profile is strongly genotype-dependent [23], recently, Sánchez-Ortiz and colleagues [15] show a clear influence of the oil extraction process on the formation of several volatiles with a high impact on EVOO's aromatic quality. Volatile compounds could be used as key biochemical markers to improve the oil extraction technology and the related sensory characteristics of the

*Dynamic headspace concentration of EVOO aroma compounds.*

*DOI: http://dx.doi.org/10.5772/intechopen.88888*

*total C6 compounds is also reported.*

*Sinolea processing system.*

**Table 7.**

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil DOI: http://dx.doi.org/10.5772/intechopen.88888*


*The percentage of the sum of C6 volatiles derived from linolenic acid (LnA) and from the linoleic acid (LA) on the total C6 compounds is also reported.*

#### **Table 7.**

*Food Processing*

**Compounds Decanter Sinolea**

2-methyl propanol 3 ± 1 15 ± 2 1 ± 1 10 ± 2

1-penten-3-ol 14 ± 4 110 ± 7 18 ± 1 72 ± 8

3-methyl butanol 3 ± 1 15 ± 1 4 ± 3 8 ± 2

2-methyl butanol 4 ± 1 32 ± 5 2 ± 1 24 ± 9

2-penten-1-ol 2 ± 1 38 ± 4 5 ± 1 29 ± 6

*Total C5 alcohols* **25 ± 4 210 ± 15 31 ± 4 143 ± 22**

1-penten-3-one 52 ± 13 629 ± 84 95 ± 9 544 ± 111

2-pentanone 4 ± 2 28 ± 11 2 ± 1 15 ± 3

3-pentanone 12 ± 1 156 ± 14 20 ± 5 103 ± 14

*Total C5 ketones* **67 ± 13 813 ± 97 117 ± 11 663 ± 116**

(*Z*)-3-hexenol 17 ± 3 42 ± 10 12 ± 5 78 ± 10

(*E*)-2-hexenol 6 ± 2 24 ± 3 3 ± 1 14 ± 3

1-hexanol 7 ± 2 18 ± 2 3 ± 2 12 ± 2

*Total C6 alcohols* **29 ± 6 84 ± 14 18 ± 5 103 ± 14**

Hexanal 24 ± 4 83 ± 18 19 ± 4 133 ± 24

(*E*)-2-hexenal 214 ± 35 712 ± 173 97 ± 9 739 ± 129

*Total C6 aldehydes* **238 ± 38 796 ± 190 117 ± 12 872 ± 144**

*Total C6 compounds* 267 ± 41 880 ± 203 135 ± 16 976 ± 158

**Total volatiles 362 ± 47 1911 ± 236 283 ± 18 1794 ± 270** *Data are expressed as ng ml−1 of oil (mean ± standard error). Percentage of the different chemical compound and class* 

*Volatile compounds detected in the headspace of the olive oils obtained from Nostrana di Brisighella cultivar* 

**1st year 2nd year 1st year 2nd year**

(1%) (1%) (0%) (1%)

(4%) (6%) (6%) (4%)

(1%) (1%) (1%) (0%)

(1%) (1%) (1%) (1%)

(1%) (2%) (2%) (2%)

**(7%) (12%) (11%) (8%)**

(15%) (34%) (33%) (30%)

(1%) (1%) (1%) (1%)

(4%) (9%) (7%) (6%)

**(20%) (45%) (42%) (38%)**

(5%) (2%) (4%) (4%)

(2%) (1%) (1%) (1%)

(2%) (1%) (1%) (1%)

**(8%) (4%) (6%) (6%)**

(7%) (4%) (7%) (8%)

(57%) (34%) (34%) (40%)

**(64%) (38%) (41%) (48%)**

(72%) (43%) (47%) (53%)

**40**

**Table 6.**

*relative to the total amount of volatiles is also shown.*

*and extracted using a decanter or a Sinolea processing system.*

*Percent distribution of the C6 volatile compounds on the total amount of C6 compounds detected in the headspace of the olive oils obtained from Nostrana di Brisighella cultivar and extracted using a decanter or a Sinolea processing system.*

#### **Figure 5.** *Dynamic headspace concentration of EVOO aroma compounds.*

Although, previous studies on different olive cultivars, including Italian varieties, evidence that aroma profile is strongly genotype-dependent [23], recently, Sánchez-Ortiz and colleagues [15] show a clear influence of the oil extraction process on the formation of several volatiles with a high impact on EVOO's aromatic quality. Volatile compounds could be used as key biochemical markers to improve the oil extraction technology and the related sensory characteristics of the obtained oils.

Therefore, from these data, it is possible to conclude that there are differences in chemical and sensory characteristics in EVOOs extracted using Sinolea and decanter.

## **4. Conclusion**

Chemical and sensory characteristics of EVOO are the result of the interaction of several factors, so in this chapter, we examine the influence of olive storage time. The time between the olive harvest and the transformation has repercussions on the quality analytical indices. These repercussions dependent on olive cultivars: in fact, Nostrana di Brisighella, Leccino, and varietal mixture had different responses in analytical indices. Probably, the difference of the specific cultivar was "silenced" in the mixed variety. Sensory analysis stressed the importance of reduction in the olive storage time before olive transformation. In fact, soon after the oil production, sensory analysis revealed only slight differences in olive oils milled both before and after 48 h. Nevertheless, the sensory analysis repeated after 12 months of oil storage revealed marked differences in the two samples.

In addition, we examine the influence of technological process on the characteristic of EVOO. From the comparison of Nostrana di Brisighella EVOO obtained by Sinolea or decanter equipment, differences in quality index and in tocopherol content were underlined. In particular, EVOO extracted by Sinolea facility had less value of peroxide number and K232 and greater amount of α tocopherol than the EVOOs extracted by decanter. As far as regard, the volatile fraction of EVOO analyzed a total of 47 compounds was found, mainly corresponding to the following chemical classes: alkanes, alcohols, aldehydes, ketones, and esters. Differences in the absolute concentrations of the volatiles of the EVOO oils obtained during the two different crop seasons were observed. The relative contribution of volatile compounds, which has an high impact on oil sensory quality, is slightly different depending on the oil extraction system. In particular, when analyzing the volatile composition based on their origin from the LOX pathway, the percentage of the sum of C6 saturated aldehydes and alcohols (i.e., volatiles derived from the LA) results higher in the oils obtained using the Sinolea system (about 15–17% of the total C6 volatiles) than the aroma profile of volatiles from LA of oils extracted using the decanter system (ca. 11–12%).

### **Acknowledgements**

Research funded by EU Commission, Regulation (EC) No 528/99, in co-operation with the Agriculture Department of Emilia Romagna region, Italy.

### **Conflict of interest**

The authors declare no conflict of interest.

### **Notes/thanks/other declarations**

The authors are grateful to Massimiliano Magli for the statistical analyses and olive growers for furnishing the olive samples.

**43**

**Author details**

Bologna, Italy

provided the original work is properly cited.

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil*

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Lucia Morrone, Annalisa Rotondi\*, Francesca Rapparini and Gianpaolo Bertazza

Institute of Bioeconomy - IBE of the Italian national Research Council,

\*Address all correspondence to: annalisa.rotondi@ibe.cnr.it

*DOI: http://dx.doi.org/10.5772/intechopen.88888*

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil DOI: http://dx.doi.org/10.5772/intechopen.88888*

## **Author details**

*Food Processing*

decanter.

**4. Conclusion**

revealed marked differences in the two samples.

Therefore, from these data, it is possible to conclude that there are differences in chemical and sensory characteristics in EVOOs extracted using Sinolea and

Chemical and sensory characteristics of EVOO are the result of the interaction of several factors, so in this chapter, we examine the influence of olive storage time. The time between the olive harvest and the transformation has repercussions on the quality analytical indices. These repercussions dependent on olive cultivars: in fact, Nostrana di Brisighella, Leccino, and varietal mixture had different responses in analytical indices. Probably, the difference of the specific cultivar was "silenced" in the mixed variety. Sensory analysis stressed the importance of reduction in the olive storage time before olive transformation. In fact, soon after the oil production, sensory analysis revealed only slight differences in olive oils milled both before and after 48 h. Nevertheless, the sensory analysis repeated after 12 months of oil storage

In addition, we examine the influence of technological process on the characteristic of EVOO. From the comparison of Nostrana di Brisighella EVOO obtained by Sinolea or decanter equipment, differences in quality index and in tocopherol content were underlined. In particular, EVOO extracted by Sinolea facility had less value of peroxide number and K232 and greater amount of α tocopherol than the EVOOs extracted by decanter. As far as regard, the volatile fraction of EVOO analyzed a total of 47 compounds was found, mainly corresponding to the following chemical classes: alkanes, alcohols, aldehydes, ketones, and esters. Differences in the absolute concentrations of the volatiles of the EVOO oils obtained during the two different crop seasons were observed. The relative contribution of volatile compounds, which has an high impact on oil sensory quality, is slightly different depending on the oil extraction system. In particular, when analyzing the volatile composition based on their origin from the LOX pathway, the percentage of the sum of C6 saturated aldehydes and alcohols (i.e., volatiles derived from the LA) results higher in the oils obtained using the Sinolea system (about 15–17% of the total C6 volatiles) than the aroma profile of volatiles from LA of oils extracted using the decanter system

Research funded by EU Commission, Regulation (EC) No 528/99, in co-opera-

The authors are grateful to Massimiliano Magli for the statistical analyses and

tion with the Agriculture Department of Emilia Romagna region, Italy.

The authors declare no conflict of interest.

olive growers for furnishing the olive samples.

**Notes/thanks/other declarations**

**42**

(ca. 11–12%).

**Acknowledgements**

**Conflict of interest**

Lucia Morrone, Annalisa Rotondi\*, Francesca Rapparini and Gianpaolo Bertazza Institute of Bioeconomy - IBE of the Italian national Research Council, Bologna, Italy

\*Address all correspondence to: annalisa.rotondi@ibe.cnr.it

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **References**

[1] Fregapane G, Salvador MD. Production of superior quality extra virgin olive oil modulating the content and profile of its minor components. Food Research International. 2013;**54**:1907-1914

[2] European Union Commission. Council Regulation(EC) 1513/2001 of 23 July 2001 amending regulation (EC)136/66/EEC and 1638/98 as regards the extension of the period of validity of the aid scheme and the quality strategyfor olive oil. Official Journal of the European Union. 2001;**L201**:4-7

[3] EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) Scientific opinion on the substantiation of health claims related to polyphenols in olive and protection of LDL particles from oxidative damage (ID 1333, 1638, 1639, 1696, 2865), maintenance of normal blood HDL-cholesterol concentrations (ID 1639), maintenance of normal blood pressure (ID 3781), anti-inflammatory properties (ID 1882), contributes to the upper respiratory tract health (ID 3468), can help to maintain a normal function of gastrointestinal tract (3779), and contributes to body defences against external agents (ID 3467) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal. 2011;**9**:2033

[4] Morrone L, Pupillo S, Neri L, Bertazza G, Magli M, Rotondi A. Influence of olive ripening degree and crusher typology on chemical and sensory characteristics of Correggiolo virgin olive oil. Journal of the Science of Food and Agriculture. 2017;**97**:1443-1450

[5] García JM, Yousfi K. The postharvest of mill olives. Grasas y Aceites. 2006;**57**:16-24

[6] Murphy DJ. Structure, function and biogenesis of storage lipid bodies and oleosin in plants. Progress in Lipid Research. 1993;**32**:247-280

[7] Olías JM, Garcia JM. Olive. In: Mitra SK, editor. Postharvest Physiological Storage of Tropical and Subtropical Fruits. New York: CAB International; 1997. pp. 229-243

[8] Clodoveo ML, Delcuratolo D, Gomes T, Colelli G. Effect of different temperatures and storage atmospheres on Coratina olive oil quality. Food Chemistry. 2007;**102**:571-576

[9] Visioli F, Galli C. The effect of minor constituents of olive oil on cardiovascular disease: New findings. Nutrition Reviews. 1998;**56**:142-147

[10] Vichi S, Romero A, Gallardo-Chacón J, Tous J, López-Tamames E, Buxaderas S. Volatile phenols in virgin olive oils: Influence of olive variety on their formation during fruits storage. Food Chemistry. 2009;**116**:651-656

[11] Rotondi A, Bertazza G, Magli M. Effect of olive fruits quality on the natural antioxidant compounds in extravirgin olive oil of Emilia-Romagna region. Progress in Nutrition. 2004;**6**:139-145

[12] Blekas G, Boskou D. Antioxidative activity of 3,4-dihydroxyplienylacetic acid and α-tocopherol on the triglyceride matrix of olive oil. Effect of acidity. Grasas y Aceites. 1998;**49**:34-37

[13] Rotondi A, Bendini A, Cerretani L, Mari M, Lercker G, Gallina Toschi T. Effect of olive ripening degree on the oxidative stability and organoleptic properties of cv. Nostrana di Brisighella extra virgin olive oil. Journal of Agricultural and Food Chemistry. 2004;**52**:3649-3654

[14] Ranalli A, Ferrante ML, De Mattia G, Costantini N. Analytical

**45**

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil*

evaluated by analytical approaches and sensor panels. European Journal of Lipid Science and Technology.

[22] Vichi S, Castellote AI, Pizzale L, Conte LS, Buxaderas S, Lopez-Tamames E. Analysis of virgin olive oil volatile compounds by headspace

[23] Angerosa F, Basti C. The volatile composition of samples from the blend of monovarietal olive oils and from the processing of mixtures of olive fruits. European Journal of Lipid Science and

Technology. 2003;**105**:327-332

solid-phase microextraction coupled to gas chromatography with mass spectrometric and flame ionization detection. Journal of Chromatography A. 2003;**983**:19-33

2002;**104**:639-660

*DOI: http://dx.doi.org/10.5772/intechopen.88888*

evaluation of virgin olive oil of first and second extraction. Journal of Agricultural and Food Chemistry.

[16] Angerosa F, Mostallino R, Basti C, Vito R, Serraiocco A. Virgin olive oil differentiation in relation to extraction methodologies. Journal of the Science of Food and Agriculture.

[17] Rapparini F, Rotondi A. Volatile compounds analysis in virgin oil by dynamic headspace method,

preliminary results. Acta Horticulturae.

[18] Vitalini S, Ruggiero A, Rapparini F, Neri L, Tonni M, Iriti M. The application of chitosan and benzothiadiazole in vineyard (*Vitis vinifera* L. cv. *Groppello gentile*) changes the aromatic profile and sensory attributes of wine. Food Chemistry. 2014;**162**:192-205. DOI: 10.1016/j.foodchem.2014.04.040

[19] Morales BMT, Angerosa F,

[20] Sánchez-Ortiz A, Pérez AG, Sanz C. Synthesis of aroma compounds of virgin olive oil: Significance of the cleavage of polyunsaturated fatty acid hydroperoxides during the oil extraction process. Food Research International. 2013;**54**:1972-1978. DOI: 10.1016/j.

[21] Angerosa F. Influence of volatile compounds on virgin olive oil quality

foodres.2013.03.045

Aparicio R, De I, Avda G, García P. Effect of the extraction conditions of virgin olive oil on the lipoxygenase cascade: Chemical and sensory implications. Grasas y Aceites. 1999;**50**:114-121

[15] Sánchez-Ortiz A, Aymen Bejaoui M, Quintero-Flores A, Jiménez A, Beltrán G. Biosynthesis of volatile compounds by hydroperoxide lyase enzymatic activity during virgin olive oil extraction process. Food Research International. 2018;**111**:220- 228. DOI: 10.1016/j.foodres.2018.05.024

1999;**47**:417-424

2000;**80**:2190-2195

2002;**586**:695-697

*Olive Processing: Influence of Some Crucial Phases on the Final Quality of Olive Oil DOI: http://dx.doi.org/10.5772/intechopen.88888*

evaluation of virgin olive oil of first and second extraction. Journal of Agricultural and Food Chemistry. 1999;**47**:417-424

[15] Sánchez-Ortiz A, Aymen Bejaoui M, Quintero-Flores A, Jiménez A, Beltrán G. Biosynthesis of volatile compounds by hydroperoxide lyase enzymatic activity during virgin olive oil extraction process. Food Research International. 2018;**111**:220- 228. DOI: 10.1016/j.foodres.2018.05.024

[16] Angerosa F, Mostallino R, Basti C, Vito R, Serraiocco A. Virgin olive oil differentiation in relation to extraction methodologies. Journal of the Science of Food and Agriculture. 2000;**80**:2190-2195

[17] Rapparini F, Rotondi A. Volatile compounds analysis in virgin oil by dynamic headspace method, preliminary results. Acta Horticulturae. 2002;**586**:695-697

[18] Vitalini S, Ruggiero A, Rapparini F, Neri L, Tonni M, Iriti M. The application of chitosan and benzothiadiazole in vineyard (*Vitis vinifera* L. cv. *Groppello gentile*) changes the aromatic profile and sensory attributes of wine. Food Chemistry. 2014;**162**:192-205. DOI: 10.1016/j.foodchem.2014.04.040

[19] Morales BMT, Angerosa F, Aparicio R, De I, Avda G, García P. Effect of the extraction conditions of virgin olive oil on the lipoxygenase cascade: Chemical and sensory implications. Grasas y Aceites. 1999;**50**:114-121

[20] Sánchez-Ortiz A, Pérez AG, Sanz C. Synthesis of aroma compounds of virgin olive oil: Significance of the cleavage of polyunsaturated fatty acid hydroperoxides during the oil extraction process. Food Research International. 2013;**54**:1972-1978. DOI: 10.1016/j. foodres.2013.03.045

[21] Angerosa F. Influence of volatile compounds on virgin olive oil quality evaluated by analytical approaches and sensor panels. European Journal of Lipid Science and Technology. 2002;**104**:639-660

[22] Vichi S, Castellote AI, Pizzale L, Conte LS, Buxaderas S, Lopez-Tamames E. Analysis of virgin olive oil volatile compounds by headspace solid-phase microextraction coupled to gas chromatography with mass spectrometric and flame ionization detection. Journal of Chromatography A. 2003;**983**:19-33

[23] Angerosa F, Basti C. The volatile composition of samples from the blend of monovarietal olive oils and from the processing of mixtures of olive fruits. European Journal of Lipid Science and Technology. 2003;**105**:327-332

**44**

*Food Processing*

**References**

[1] Fregapane G, Salvador MD. Production of superior quality extra virgin olive oil modulating the content and profile of its minor components.

and oleosin in plants. Progress in Lipid

Research. 1993;**32**:247-280

[7] Olías JM, Garcia JM. Olive. In: Mitra SK, editor. Postharvest Physiological Storage of Tropical and Subtropical Fruits. New York: CAB International; 1997. pp. 229-243

[8] Clodoveo ML, Delcuratolo D, Gomes T, Colelli G. Effect of different temperatures and storage atmospheres on Coratina olive oil quality. Food Chemistry. 2007;**102**:571-576

[9] Visioli F, Galli C. The effect of minor constituents of olive oil on cardiovascular disease: New findings. Nutrition Reviews. 1998;**56**:142-147

[10] Vichi S, Romero A, Gallardo-Chacón J, Tous J, López-Tamames E, Buxaderas S. Volatile phenols in virgin olive oils: Influence of olive variety on their formation during fruits storage. Food Chemistry. 2009;**116**:651-656

[11] Rotondi A, Bertazza G, Magli M. Effect of olive fruits quality on the natural antioxidant compounds in extravirgin olive oil of Emilia-Romagna

[12] Blekas G, Boskou D. Antioxidative activity of 3,4-dihydroxyplienylacetic

triglyceride matrix of olive oil. Effect of acidity. Grasas y Aceites. 1998;**49**:34-37

Cerretani L, Mari M, Lercker G, Gallina Toschi T. Effect of olive ripening degree on the oxidative stability and organoleptic properties of cv. Nostrana di Brisighella extra virgin olive oil. Journal of Agricultural and Food Chemistry. 2004;**52**:3649-3654

region. Progress in Nutrition.

acid and α-tocopherol on the

[13] Rotondi A, Bendini A,

[14] Ranalli A, Ferrante ML, De Mattia G, Costantini N. Analytical

2004;**6**:139-145

Food Research International.

[2] European Union Commission. Council Regulation(EC) 1513/2001 of 23 July 2001 amending regulation (EC)136/66/EEC and 1638/98 as regards the extension of the period of validity of the aid scheme and the quality strategyfor olive oil. Official Journal of the European Union. 2001;**L201**:4-7

[3] EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)

Scientific opinion on the substantiation of health claims related to polyphenols in olive and protection of LDL particles from oxidative damage (ID 1333, 1638, 1639, 1696, 2865), maintenance of normal blood HDL-cholesterol concentrations (ID 1639), maintenance of normal blood pressure (ID 3781), anti-inflammatory properties (ID 1882), contributes to the upper

respiratory tract health (ID 3468), can help to maintain a normal function of gastrointestinal tract (3779), and contributes to body defences against external agents (ID 3467) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal. 2011;**9**:2033

[4] Morrone L, Pupillo S, Neri L, Bertazza G, Magli M, Rotondi A. Influence of olive ripening degree and crusher typology on chemical and sensory characteristics of

2017;**97**:1443-1450

2006;**57**:16-24

Correggiolo virgin olive oil. Journal of the Science of Food and Agriculture.

[5] García JM, Yousfi K. The postharvest

of mill olives. Grasas y Aceites.

[6] Murphy DJ. Structure, function and biogenesis of storage lipid bodies

2013;**54**:1907-1914

**47**

**Chapter 3**

**Abstract**

processing.

**1. Introduction**

determined.

Powder Technology

*Suzana Caetano da Silva Lannes* 

*and Maria Elena Del Dolores Bernal Gómez*

Combining two or more granular or powder ingredients requires a suitable mixing process, which can be either free or random flow with no attraction forces between the particles or interactive or orderly with the presence of large active particles that attract others forming stable clumps. Food systems have very complex properties that make it difficult to standardize the mixing process. In order to achieve an efficient mixture, diffusive and convective mechanisms must be combined, and its success is achieved with a predominance of homogenization over segregation. Powder products are typically used in industry as dispersion in a liquid and should have some properties such as good wettability, water incorporation, flowability, and instantization. To work with powder products, it is necessary to make determinations such as density, particle size, texture, and compaction force, among others. All these physical properties affect and determine the behavior of powdered products during storage, handling, and

**Keywords:** physical properties, powder products, solid particles, mix process

Power mixing involves several steps. The first one could be mentioned as a classification of the powder particles. Flowability can be the result of a good classification step. Consistent feed from bulk storage containers into feed mechanisms of subsequent processing operations is necessary. Interparticle forces, including van der Waals forces, capillary, and electrostatic forces influence the behavior of powder flow systems, as well as a small amount of moisture. Flow properties as angle of internal friction related to cohesion force of solids are also

Powder mixing requires a statistical methodology before choosing the right equipment. Only in this way is a satisfactory result obtained, with the distribution

Segregation tends to occur whenever bulk material moves, and it occurs where differential forces act on different fractions of the mass of bulk material, and when differences in particulate properties cause a preferential movement of particles.

The quality of mix and characterizing it requires taking several samples and analyzing them, as a random way. Measurement of the mixing profile in real time with near infrared (NIR) provides the opportunity to study the dynamics of powder

of the mixture components as close as possible to ideality.

mixing and enabling a more comprehensive statistical analysis [1].

This chapter aims to present some aspects of this powder technology.

## **Chapter 3** Powder Technology

*Suzana Caetano da Silva Lannes and Maria Elena Del Dolores Bernal Gómez*

## **Abstract**

Combining two or more granular or powder ingredients requires a suitable mixing process, which can be either free or random flow with no attraction forces between the particles or interactive or orderly with the presence of large active particles that attract others forming stable clumps. Food systems have very complex properties that make it difficult to standardize the mixing process. In order to achieve an efficient mixture, diffusive and convective mechanisms must be combined, and its success is achieved with a predominance of homogenization over segregation. Powder products are typically used in industry as dispersion in a liquid and should have some properties such as good wettability, water incorporation, flowability, and instantization. To work with powder products, it is necessary to make determinations such as density, particle size, texture, and compaction force, among others. All these physical properties affect and determine the behavior of powdered products during storage, handling, and processing.

**Keywords:** physical properties, powder products, solid particles, mix process

## **1. Introduction**

Power mixing involves several steps. The first one could be mentioned as a classification of the powder particles. Flowability can be the result of a good classification step. Consistent feed from bulk storage containers into feed mechanisms of subsequent processing operations is necessary. Interparticle forces, including van der Waals forces, capillary, and electrostatic forces influence the behavior of powder flow systems, as well as a small amount of moisture. Flow properties as angle of internal friction related to cohesion force of solids are also determined.

Powder mixing requires a statistical methodology before choosing the right equipment. Only in this way is a satisfactory result obtained, with the distribution of the mixture components as close as possible to ideality.

Segregation tends to occur whenever bulk material moves, and it occurs where differential forces act on different fractions of the mass of bulk material, and when differences in particulate properties cause a preferential movement of particles.

The quality of mix and characterizing it requires taking several samples and analyzing them, as a random way. Measurement of the mixing profile in real time with near infrared (NIR) provides the opportunity to study the dynamics of powder mixing and enabling a more comprehensive statistical analysis [1].

This chapter aims to present some aspects of this powder technology.

## **2. Sieving**

Before starting a powder mixing process, a classification and maybe separation of the particles is necessary.

Sieving process is the separation of a mixture of grains of different sizes in two or more plots, through a sieving surface, which acts as a gauge that allows and does not let the grains pass. The final plots consist of more uniformly sized grain than the original blend. Mesh is the number of apertures of a screen of the same dimension in each linear inch, counted from the center of any wire to a point exactly 1 in (25.4 mm), or by a specified aperture in inches or millimeters, which is understood to be the free opening or space between the wires. Example: A granular material (−10 + 100) means that everything passes through a 10-mesh sieve (particles smaller than 1.68 mm) and nothing passes through a 100 mesh (particles larger than 0.149 mm). Screen opening is the minimum clear space between the edges of the openings on the sieving surface, given in inches or mm.

Particle size distribution is the relative percentage by weight of the grains that constitute the different size fractions present in the sample. It is one of the most important factors in evaluating the screening operation and is best determined by a full-size analysis using test sieves.

## **3. Powder mix**

Mixture can be defined as the result of combining two or more ingredients. It can be granular or powdery. For such granular or powder mixtures to be formed a suitable mixing process is required. According to Pernenkil and Cooney [2], powder mixing is a crucial unit operation in the food industry.

Mixing is considered as a critical factor, especially in case of strong drugs and low dose drugs where high amounts of adjuvants are added.

There are two types of mixtures, non-interactive or random, and interactive or ordered. The first are those of free flow, being mixtures of uniform particle size powders or grains, without intraparticle forces of attraction, thus flowing with little interruption. Consequently, each different particle will have the same probability of being found in any portion of the mixture. Interactive mixing is formed when large active surface particles exist where other particles are attracted. They form stable clusters and the force between the particles belongs to different chemical classes [3].

According to Fellows [4], it is not possible to obtain a completely uniform mixture of powder products or particulate solids, but according to Singh and Heldman [5], the most important fact in a mixture is the reduction of random mix variation.

There are basically three mechanisms in mixing solids: diffusion, convection and shear. Shear can be considered as convective, and efficient mixing must be combined by diffusive and convective mechanisms. A purely diffusion process generates high efficiency in the mixing of individual particles, however, occurs at a low rate. The basically convective process is fast but less effective, exhibiting an ineffective final blend. For solids the diffusive mixture will only occur by mechanical agitation. The particles will change their collective or individual relative positions, and segregation of the particles may also occur, occurring when particles of different sizes, shapes or densities are mixed. A good mix occurs when there is homogeneity of the particles.

It is difficult to define and evaluate the powder mix; but certain quantitative measurements in solids can help estimate mixer performance. The proof of the mixer in practice comes from the properties it provides to the final blend produced by it (**Figure 1**).

**49**

**4. Physical properties**

*Powder Technology*

mixture (Eq. 1).

a sample.

**Figure 1.** *Mixers.*

*DOI: http://dx.doi.org/10.5772/intechopen.90715*

The design of the mixer and its operation must be carefully chosen to achieve the

<sup>σ</sup><sup>0</sup> <sup>−</sup>σ∞ σ<sup>0</sup> − √[*V*1(1 − *V*<sup>1</sup> )] (1)

Mixing index involves the comparison of standard deviation of sample of a mixture under study with the estimated standard deviation of a completely random

where *σ*∞ = the standard deviation of a 'perfectly mixed' sample, *σ*o = the standard deviation of a sample at the start of mixing and *σ*m = the standard deviation of

*V* = the average fractional volume or mass of a component in the mixture [4]. Due to the complexity of the properties of food systems, which may vary during the mixing process, it is extremely difficult to generalize or standardize the mixing operation for various new or traditional applications. The development of mathematical modeling for the food mixing process is also scarce, and it is necessary to

Near-Infrared (NIR) spectroscopy can be used of in-situ as the basis for an in-

Some recommendations before starting the process: Determine which particle properties are required to solve your problem; For the form it is necessary to use an image analyzer. If not, assume that the measured size is an equivalent spherical diameter; for many non-spherical particles do not try different techniques for size checking. Many particles are globular enough to be considered spherical in order to do a job.

Powder products have different physical properties that must be measured and

Detailed information on the physical properties of powder products is required,

Some forces acting on the particles, as Van der Waals, electrostatic, and surfaces forces. Cohesive forces and frictional forces result in surface-surface interactions which

desired results [4], as this influences the final product quality [6].

\_ σ*<sup>m</sup>* − σ∞

consult established procedures for equipment design or scaling up [3].

line control system to optimize mixing time of food powder blends [7].

studied to obtain a product with the desired characteristics.

especially as they are complex products [8].

*M*<sup>1</sup> =

## *Powder Technology DOI: http://dx.doi.org/10.5772/intechopen.90715*

**Figure 1.** *Mixers.*

*Food Processing*

**2. Sieving**

of the particles is necessary.

full-size analysis using test sieves.

**3. Powder mix**

openings on the sieving surface, given in inches or mm.

mixing is a crucial unit operation in the food industry.

low dose drugs where high amounts of adjuvants are added.

Before starting a powder mixing process, a classification and maybe separation

Sieving process is the separation of a mixture of grains of different sizes in two or more plots, through a sieving surface, which acts as a gauge that allows and does not let the grains pass. The final plots consist of more uniformly sized grain than the original blend. Mesh is the number of apertures of a screen of the same dimension in each linear inch, counted from the center of any wire to a point exactly 1 in (25.4 mm), or by a specified aperture in inches or millimeters, which is understood to be the free opening or space between the wires. Example: A granular material (−10 + 100) means that everything passes through a 10-mesh sieve (particles smaller than 1.68 mm) and nothing passes through a 100 mesh (particles larger than 0.149 mm). Screen opening is the minimum clear space between the edges of the

Particle size distribution is the relative percentage by weight of the grains that constitute the different size fractions present in the sample. It is one of the most important factors in evaluating the screening operation and is best determined by a

Mixture can be defined as the result of combining two or more ingredients. It can be granular or powdery. For such granular or powder mixtures to be formed a suitable mixing process is required. According to Pernenkil and Cooney [2], powder

Mixing is considered as a critical factor, especially in case of strong drugs and

There are two types of mixtures, non-interactive or random, and interactive or ordered. The first are those of free flow, being mixtures of uniform particle size powders or grains, without intraparticle forces of attraction, thus flowing with little interruption. Consequently, each different particle will have the same probability of being found in any portion of the mixture. Interactive mixing is formed when large active surface particles exist where other particles are attracted. They form stable clusters and the force between the particles belongs to different chemical classes [3]. According to Fellows [4], it is not possible to obtain a completely uniform mixture of powder products or particulate solids, but according to Singh and Heldman [5], the most important fact in a mixture is the reduction of random mix variation. There are basically three mechanisms in mixing solids: diffusion, convection and

shear. Shear can be considered as convective, and efficient mixing must be combined by diffusive and convective mechanisms. A purely diffusion process generates high efficiency in the mixing of individual particles, however, occurs at a low rate. The basically convective process is fast but less effective, exhibiting an ineffective final blend. For solids the diffusive mixture will only occur by mechanical agitation. The particles will change their collective or individual relative positions, and segregation of the particles may also occur, occurring when particles of different sizes, shapes or densities are mixed. A good mix occurs when there is homogeneity

It is difficult to define and evaluate the powder mix; but certain quantitative measurements in solids can help estimate mixer performance. The proof of the mixer in practice comes from the properties it provides to the final blend produced

**48**

of the particles.

by it (**Figure 1**).

The design of the mixer and its operation must be carefully chosen to achieve the desired results [4], as this influences the final product quality [6].

Mixing index involves the comparison of standard deviation of sample of a mixture under study with the estimated standard deviation of a completely random mixture (Eq. 1). \_

$$M\_1 = \frac{\sigma\_{\text{in}} - \sigma\_{\text{os}}}{\sigma\_0 - \sigma\_{\text{os}}} \ \sigma\_0 - \sqrt{\left[V\_1(1 - V\_1)\right]} \tag{1}$$

where *σ*∞ = the standard deviation of a 'perfectly mixed' sample, *σ*o = the standard deviation of a sample at the start of mixing and *σ*m = the standard deviation of a sample.

*V* = the average fractional volume or mass of a component in the mixture [4].

Due to the complexity of the properties of food systems, which may vary during the mixing process, it is extremely difficult to generalize or standardize the mixing operation for various new or traditional applications. The development of mathematical modeling for the food mixing process is also scarce, and it is necessary to consult established procedures for equipment design or scaling up [3].

Near-Infrared (NIR) spectroscopy can be used of in-situ as the basis for an inline control system to optimize mixing time of food powder blends [7].

Some recommendations before starting the process: Determine which particle properties are required to solve your problem; For the form it is necessary to use an image analyzer. If not, assume that the measured size is an equivalent spherical diameter; for many non-spherical particles do not try different techniques for size checking. Many particles are globular enough to be considered spherical in order to do a job.

## **4. Physical properties**

Powder products have different physical properties that must be measured and studied to obtain a product with the desired characteristics.

Detailed information on the physical properties of powder products is required, especially as they are complex products [8].

Some forces acting on the particles, as Van der Waals, electrostatic, and surfaces forces. Cohesive forces and frictional forces result in surface-surface interactions which resist the movement of particles, and they should be minimal. During mixing, the particles develop surface charge, which produces repulsions between particles, occurring random mixing, depending on surface properties, polarity, charge, and moisture.

Normally, powder products are used in industry as dispersion in a liquid. The wettability test is a simple test used by industry that provides the time parameter required for the powder to be absorbed by a liquid. Although maximum product wetting time is an arbitrary choice, powders in which 90% of the sample has already been dipped within 5 minutes are good wetting [9].

Powder flowability is defined as the ease with which a powder will flow under a specified set of conditions. Some of these conditions include the pressure on the powder, the humidity of the air around the powder and the equipment the powder is flowing through or from. Quantify powder flow characteristics are Compaction, Cohesion, Compressibility and Bulk Density. Flowability cannot showed as a single value or index, due to the combinations of physical properties of materials, the used equipment and processing.

Some physical properties of the powders such as angle of repose or rest angle are of importance for information on product flowability. During powder reconstitution, surface moisturizing water molecules tend to reduce inter-particle cohesiveness, thus allowing faster water penetration, so powders with high angle of repose have greater difficulty in incorporating water [10]. Powders with an angle of repose of up to 40o usually flow easily, if the angle exceeds 50o the flowability may be impaired indicating lower flowability. Particulate solids with up to 35<sup>o</sup> angle of repose have good flowability, those of 35 - 45<sup>o</sup> have poor cohesiveness, those of 45 - 55<sup>o</sup> have good cohesiveness and those above 55<sup>o</sup> are very cohesive, with low cohesive cocoa powder (45°) and cohesive (52°) cupuassu powder, for example [11]. Some powders show changes in fluidity with storage time [12].

The settled density of powders can be easily determined with a graduated cylinder (20 g sample) with some stirring to constant volume [12]. For example, cupuassu powder has 0.53 g/mL and cocoa powder 0.51 g/mL [11]. Shittu and Lawal [10] analyzed commercial chocolate and found values ranging from 0.49 to 0.81 g/cm3 . Eduardo [13] found values ranging from 0.28 to 0.94 g/cm3 for chocolate drink powder from market.

Some powder properties:

#### 1.Wettability

Time required for a specific amount of dust to be completely wetted when it is placed in water at a specific temperature. It is mainly related to particle size and shape, temperature and liquid type. Particle surface characteristics and fat content and characteristics if present and the correlation between wettability and fat content are inverse. Important analysis for powder products that will undergo the reconstitution process, as from the wettability analysis can obtain information about the product, such as its dispersibility and tendency to agglomerate formation. The wettability test is used by industry and it is the most important step in the process of reconstituting powder products.

Within this physical property of powders, there are some forms of measurement such as immersion, capillary rise, condensation and spreading. Immersion is the traditional method, which is used in powders that wet reasonably well [14].

#### 2.Solubility index

Determines the ability of the powder to dissolve in water. It is defined as the volume of sediment in mL after centrifugation. The powder is dissolved in water at

**51**

*Powder Technology*

1250 times).

particle sizes [15].

sieve [16].

ranges.

charge.

compaction.

irregular shapes.

*DOI: http://dx.doi.org/10.5772/intechopen.90715*

3.Bulk/tapped density

4.Particle size distribution

food industries, among others [17].

a certain temperature and centrifuged. The supernatant is removed and replaced with water and centrifuged before reading the volume of insoluble residue.

It is the weight of the powder divided by the volume occupied, usually expressed in g/mL. The sample is placed in an aluminum cylinder, heavy and beaten (100 or

Particle size is a determining parameter in the effectiveness of homogeneity in a powder mix when these are mixtures of two or more components of different

Sieves can be used. The dust sample is divided into fractions with different

Particle size distribution and particle size are of utmost importance when studying powder products. The particle size distribution can be represented graphically by the accumulated relative frequency (usually given as a percentage) or by size frequency histograms at certain intervals. It should be considered in the analysis that more than 20% of the material cannot be retained in the first sieve or bottom, and more than 30% of the material cannot be retained in any intermediate

The physical properties of powdered products affect their behavior during storage, handling and processing. Therefore, the determination of such parameters is of great importance for industries that use powders as raw material or even as final product. This is the case in the building materials, ceramics, pharmaceuticals and

Properties of the ingredients of a match that affect the mixing of solids:

1.Particle size distribution—reports the material fractions at different size

2.Bulk density—weight per unit volume of solid particles. It is not a constant. It can be diminished by aeration and increased by vibration or mechanical

3.Particle shape—ovoids, blocks, spheres, flakes, chips, rods, filaments, crystals,

4.Surface characteristics - surface area and the tendency to retain electrical

not flow satisfactorily. With about 25° will flow easily (**Figure 2**).

6.Reliability—is the tendency of the material to break during the handling operation. One should also consider the abrasion between the ingredients.

5.Flow characteristics—rest angle and flowability. They are measurable characteristics determined in standardized assays. A higher rest angle indicates lower flowability. An object resting on an inclined plane begins to slide when the inclination angle is increased sufficiently to overlap the frictional force between the object and the plane. In general, if the angle exceeds 50° the powder will

particle sizes by sieving, or by Laiser (Mastersizer Malvern Equipment).

a certain temperature and centrifuged. The supernatant is removed and replaced with water and centrifuged before reading the volume of insoluble residue.

3.Bulk/tapped density

*Food Processing*

resist the movement of particles, and they should be minimal. During mixing, the particles develop surface charge, which produces repulsions between particles, occurring random mixing, depending on surface properties, polarity, charge, and moisture. Normally, powder products are used in industry as dispersion in a liquid. The wettability test is a simple test used by industry that provides the time parameter required for the powder to be absorbed by a liquid. Although maximum product wetting time is an arbitrary choice, powders in which 90% of the sample has already

Powder flowability is defined as the ease with which a powder will flow under a specified set of conditions. Some of these conditions include the pressure on the powder, the humidity of the air around the powder and the equipment the powder is flowing through or from. Quantify powder flow characteristics are Compaction, Cohesion, Compressibility and Bulk Density. Flowability cannot showed as a single value or index, due to the combinations of physical properties of materials, the used

Some physical properties of the powders such as angle of repose or rest angle are of importance for information on product flowability. During powder reconstitution, surface moisturizing water molecules tend to reduce inter-particle cohesiveness, thus allowing faster water penetration, so powders with high angle of repose have greater difficulty in incorporating water [10]. Powders with an angle

usually flow easily, if the angle exceeds 50o

cohesive cocoa powder (45°) and cohesive (52°) cupuassu powder, for example [11].

The settled density of powders can be easily determined with a graduated cylinder

may be impaired indicating lower flowability. Particulate solids with up to 35<sup>o</sup>

(20 g sample) with some stirring to constant volume [12]. For example, cupuassu powder has 0.53 g/mL and cocoa powder 0.51 g/mL [11]. Shittu and Lawal [10] analyzed commercial chocolate and found values ranging from 0.49 to 0.81 g/cm3

Time required for a specific amount of dust to be completely wetted when it is placed in water at a specific temperature. It is mainly related to particle size and shape, temperature and liquid type. Particle surface characteristics and fat content and characteristics if present and the correlation between wettability and fat content are inverse. Important analysis for powder products that will undergo the reconstitution process, as from the wettability analysis can obtain information about the product, such as its dispersibility and tendency to agglomerate formation. The wettability test is used by industry and it is the most important step in the

Within this physical property of powders, there are some forms of measurement such as immersion, capillary rise, condensation and spreading. Immersion is the traditional method, which is used in powders that wet reasonably well [14].

Determines the ability of the powder to dissolve in water. It is defined as the volume of sediment in mL after centrifugation. The powder is dissolved in water at

the flowability

for chocolate drink powder

have poor cohesiveness, those of

are very cohesive, with low

angle

.

been dipped within 5 minutes are good wetting [9].

of repose have good flowability, those of 35 - 45<sup>o</sup>

have good cohesiveness and those above 55<sup>o</sup>

Eduardo [13] found values ranging from 0.28 to 0.94 g/cm3

Some powders show changes in fluidity with storage time [12].

equipment and processing.

of repose of up to 40o

45 - 55<sup>o</sup>

from market.

1.Wettability

2.Solubility index

Some powder properties:

process of reconstituting powder products.

**50**

It is the weight of the powder divided by the volume occupied, usually expressed in g/mL. The sample is placed in an aluminum cylinder, heavy and beaten (100 or 1250 times).

## 4.Particle size distribution

Particle size is a determining parameter in the effectiveness of homogeneity in a powder mix when these are mixtures of two or more components of different particle sizes [15].

Sieves can be used. The dust sample is divided into fractions with different particle sizes by sieving, or by Laiser (Mastersizer Malvern Equipment).

Particle size distribution and particle size are of utmost importance when studying powder products. The particle size distribution can be represented graphically by the accumulated relative frequency (usually given as a percentage) or by size frequency histograms at certain intervals. It should be considered in the analysis that more than 20% of the material cannot be retained in the first sieve or bottom, and more than 30% of the material cannot be retained in any intermediate sieve [16].

The physical properties of powdered products affect their behavior during storage, handling and processing. Therefore, the determination of such parameters is of great importance for industries that use powders as raw material or even as final product. This is the case in the building materials, ceramics, pharmaceuticals and food industries, among others [17].

Properties of the ingredients of a match that affect the mixing of solids:


Segregation mechanisms can occur with poor flow properties, particle size difference, difference in mobilities and in particle density and shape, transporting methods, dusting stage. Can be summarized as:


**Figure 2.** *Rest angle determination.*

**53**

*Powder Technology*

**4.1 Compression**

[11, 13, 18].

neous powder is desired.

*DOI: http://dx.doi.org/10.5772/intechopen.90715*

distances determined in the first test (**Figure 3**).

the larger ones (particle percolation).

action of agglomeration [9, 20].

as showed by Barros [21].

**5. Instantization**

Compaction can be understood as the compression of a two-phase system, solid and gas (dust and air), under the action of a force, which results in a reduction in the volume of the product. Compaction determination is useful for flow evaluation, friction tendency and dust agglomeration. In industry, the compaction process is used when forming powders, such as tablets. Under a compressive force, the particles rearrange (increasing the density of the dust), deform, and fragment

However, these transformations continue to happen even when compression is not desired. Cartwright [19] associated the dispersibility of powders with their texture. He stated that very fine particles should be avoided when a good instanta-

Eduardo and Lannes [16] developed a methodology for determining the compaction strength of powders using the TA-XT2 texturometer and the *back extrusion* probe. Medeiros [9] complemented with the compression distance test, aiming to determine the maximum volume reduction occupied by the sample, but that would not exceed the 20,000 g force. The compression strength test is performed at the

The relationship between the compaction force and the compaction capacity of the sample is inversely proportional; hence, a sample is most compactable if its compaction force is lower. Based on these data, the most compactable sample was cocoa, as it presented the lowest compaction force, and the least compactable was

Eduardo and Lannes [13, 16] determined the compaction force of commercial chocolate, the results obtained ranged from 532 to 16,399 g. From these results the chocolate products were classified as very compact, with force below 2000 g and little compact, with force above 2000 g. These results also depend on the intrinsic

In granular materials (such as powders) pressure can cause permanent volume change. The removal of air between particles, causing a change in dust volume, can be caused throughout the storage period, transportation or even processing if some type of vibration is involved. Powder products contain in their formulation a great diversity of ingredients with distinct particle characteristics, and the reduction in volume is due to the accommodation of smaller particles between the space left by

The instantization property identifies foods that are easy to solubilize in cold water, obtained in the drying process using dispersing substances, or through the

Several physical and chemical methods have been employed to improve the instant properties of powdered foods, as is the case of adding cereal alcohol with its subsequent evaporation under controlled time, temperature and relative humidity,

One of the methods used to achieve instantization of powdered products is the

Spray-drying technology is widely used in various industrial segments including

pharmaceutical and food. Although it is a technology that requires large investments in facilities and operation, there are many reasons why it is widely used. These advantages include consistent quality particle production, continuous use,

spray-drying procedure that atomizes a solution by hot air [9, 22].

cupuassu powder, there was no significant difference between them [16].

characteristics of the particles, such as shape, size and homogeneity.

**Figure 3.** *Texturometer,* back extrusion *probe and cylindrical cup with sample.*

## **4.1 Compression**

*Food Processing*

liquid.

change must be observed.

methods, dusting stage. Can be summarized as:

2.Increase of coarse particles in vibration.

*Texturometer,* back extrusion *probe and cylindrical cup with sample.*

7.Agglomeration state—refers to the independent existence of particles or their adherence to each other, forming aggregates. The type and amount of energy employed during mixing and the friability of the agglomerates will influence

8.Moisture or liquid content in the solid—often a small amount of liquid is added

9.Viscosity and surface tension—at the operating temperature of any added

10. Thermal Limitations of Ingredients—Any effect caused by temperature

Segregation mechanisms can occur with poor flow properties, particle size difference, difference in mobilities and in particle density and shape, transporting

1.Fine particle percolation. If a particle mass is disturbed such that individual

particles move, a rearrangement of the particle packing occurs;

aggregate breakdown and particle dispersion.

to the solid to reduce dust or satisfy a special need.

**52**

**Figure 3.**

**Figure 2.**

*Rest angle determination.*

Compaction can be understood as the compression of a two-phase system, solid and gas (dust and air), under the action of a force, which results in a reduction in the volume of the product. Compaction determination is useful for flow evaluation, friction tendency and dust agglomeration. In industry, the compaction process is used when forming powders, such as tablets. Under a compressive force, the particles rearrange (increasing the density of the dust), deform, and fragment [11, 13, 18].

However, these transformations continue to happen even when compression is not desired. Cartwright [19] associated the dispersibility of powders with their texture. He stated that very fine particles should be avoided when a good instantaneous powder is desired.

Eduardo and Lannes [16] developed a methodology for determining the compaction strength of powders using the TA-XT2 texturometer and the *back extrusion* probe. Medeiros [9] complemented with the compression distance test, aiming to determine the maximum volume reduction occupied by the sample, but that would not exceed the 20,000 g force. The compression strength test is performed at the distances determined in the first test (**Figure 3**).

The relationship between the compaction force and the compaction capacity of the sample is inversely proportional; hence, a sample is most compactable if its compaction force is lower. Based on these data, the most compactable sample was cocoa, as it presented the lowest compaction force, and the least compactable was cupuassu powder, there was no significant difference between them [16].

Eduardo and Lannes [13, 16] determined the compaction force of commercial chocolate, the results obtained ranged from 532 to 16,399 g. From these results the chocolate products were classified as very compact, with force below 2000 g and little compact, with force above 2000 g. These results also depend on the intrinsic characteristics of the particles, such as shape, size and homogeneity.

In granular materials (such as powders) pressure can cause permanent volume change. The removal of air between particles, causing a change in dust volume, can be caused throughout the storage period, transportation or even processing if some type of vibration is involved. Powder products contain in their formulation a great diversity of ingredients with distinct particle characteristics, and the reduction in volume is due to the accommodation of smaller particles between the space left by the larger ones (particle percolation).

## **5. Instantization**

The instantization property identifies foods that are easy to solubilize in cold water, obtained in the drying process using dispersing substances, or through the action of agglomeration [9, 20].

Several physical and chemical methods have been employed to improve the instant properties of powdered foods, as is the case of adding cereal alcohol with its subsequent evaporation under controlled time, temperature and relative humidity, as showed by Barros [21].

One of the methods used to achieve instantization of powdered products is the spray-drying procedure that atomizes a solution by hot air [9, 22].

Spray-drying technology is widely used in various industrial segments including pharmaceutical and food. Although it is a technology that requires large investments in facilities and operation, there are many reasons why it is widely used. These advantages include consistent quality particle production, continuous use,

#### *Food Processing*

the applicability of the technique to thermosensitive and heat resistant materials, the ability to process various types of raw materials, and the flexibility to define a project based in the formulation. To make use of these advantages, there are several aspects that must be considered. These include the evaluation of the formulation and process parameters, the specific type of particle to be produced and the properties of the material used [9, 23].

Mist drying is the transformation of low or high viscosity liquids, even those that are almost pasty, into dry and pulverized product in a single operation. The liquid or paste is atomized using a centrifugal or high-pressure system where the atomized droplets immediately meet a hot air flow. The rapid evaporation allows keeping the temperature of the product low. Heat and mass transfer are accomplished by direct contact between the hot gas and the dispersed droplets. Fine particles are separated from gas in external cyclones or collecting sleeves. When only the coarse fraction of the finished product is desired, the fines can be recovered in washers; washer liquid is concentrated and returned to the dryer [24–26].

The main use of spray dryers is the drying of solutions and aqueous suspensions. They are also used in combined drying and heat treatment operations. Feed is usually a liquid solution, suspension or paste that can be sprayed [9, 27]. The product to be dried goes through nozzles of varying sizes, influencing the particle size obtained, the liquid part is transformed into an atomized spray. The dust is carried in an airstream that carries it in contact with the spray.

Improvement of the physical and chemical characteristics of the materials used in this technique generally involves the comparison of process parameters such as heating, air volume, atomizer nozzle type, flow rate of the material to be dried or atomization system, drying air temperature. Formulation parameters are evaluated together with process parameters. It is important to check, for example, when the temperature is raised, if there is no extensive protein denaturation, loss of flavor, as well as impairment of solubility, stability and compaction [23, 28].

Heating and mass transfer during drying occur with air and vapor films around the droplets. This vapor shield keeps the particle at saturation temperature. As the particle does not become dry, evaporation continues, and the temperature of the solids does not approach the temperature of the drying outlet. Because of this, sensitive products can be dried at relatively high temperatures.

The shape of most atomized particles is spherical, which ensures fluid-like flow. This helps in the handling and filling process, for example, as well as in reducing costs. The particles still have homogeneity in the composition and the particle size distribution is very close, minimizing the obtaining of very fine particles, which is very important for the obtained product.

Factors such as humidity and water activity are of great importance in the study of the obtained product. Process definition and suitability of equipment operating parameters are particular to each desired finished product, depending on the characteristics it is intended to provide [29].

As the spray-dryer technique is widely used in the industry, the study of its potentiality and suitability to obtain powder products is a way to study the drying process for this and other products, as well as explore the equipment and its resources, obtaining a differentiated product. Instantization and improving product wettability are very important factors in obtaining a powder product, where the drying technique becomes a means to obtain these characteristics. Straatsma et al. [30] studied the solubility index of spray-dryer instantized materials, and this index is of primary importance for instantized powders. The thermal load of food products during drying is an important factor in the final quality of the powder, since heat exposure can lead to the formation of insoluble materials which are undesirable especially for instant powders. Spray-dryer equipment can be seen in **Figure 4**.

**55**

**Figure 4.**

*Powder Technology*

*DOI: http://dx.doi.org/10.5772/intechopen.90715*

Optimal selection of inlet and outlet temperature differences is one of the most

Product feeding and the introduction of the drying air in this type of dryer are performed at the top of the chamber in co-current flow system. Drying takes place while hot air and the product in the form of small droplets travel through the drying chamber to its conical base. Moist air and dry product then follow to the cyclone, where they are separated, and moist air is removed, and the dry powder product is

Atomizing a powder mixture involves a combination of ingredients, improving wettability in water or another liquid, evening out powder particles as well as improving their flowability and dispersibility. Its high cost must be offset by these factors [32]. Dispersibility is the ability of the powder concentrate to suspend in water to form finely divided particles that will remain in suspension for a reasonable period. It is described as a carrier surface feature and dispersing agents are added by overlapping the forces of attraction between the particles [33]. The dispersion of solids is affected by the texture of the powder, and to be instantaneous the powder must be optimal in size and very fine particles should be avoided [19]. Proper formulation requires a balance between aggregate size and interactions between different

chemical additives, as well as adjustment of grinding process conditions.

important aspects of spray-dryer. The outlet temperature cannot be chosen as desired as it results from the combination of inlet temperature - vacuum adjustment

*Scheme of spray-dryer and drying air flow [31] 1. Air inlet, 2. Heating, 3. Entering the drying chamber, 4. Cyclone, 5. Vacuum Cleaner, 6. Control of inlet air temperature, 7. Control of outlet air temperature* 

and product feed pump performance.

*and 8. Receiving vessel of final product.*

collected at the base of the cyclone.

#### **Figure 4.**

*Food Processing*

ties of the material used [9, 23].

is concentrated and returned to the dryer [24–26].

in an airstream that carries it in contact with the spray.

well as impairment of solubility, stability and compaction [23, 28].

sensitive products can be dried at relatively high temperatures.

very important for the obtained product.

characteristics it is intended to provide [29].

the applicability of the technique to thermosensitive and heat resistant materials, the ability to process various types of raw materials, and the flexibility to define a project based in the formulation. To make use of these advantages, there are several aspects that must be considered. These include the evaluation of the formulation and process parameters, the specific type of particle to be produced and the proper-

Mist drying is the transformation of low or high viscosity liquids, even those that are almost pasty, into dry and pulverized product in a single operation. The liquid or paste is atomized using a centrifugal or high-pressure system where the atomized droplets immediately meet a hot air flow. The rapid evaporation allows keeping the temperature of the product low. Heat and mass transfer are accomplished by direct contact between the hot gas and the dispersed droplets. Fine particles are separated from gas in external cyclones or collecting sleeves. When only the coarse fraction of the finished product is desired, the fines can be recovered in washers; washer liquid

The main use of spray dryers is the drying of solutions and aqueous suspensions. They are also used in combined drying and heat treatment operations. Feed is usually a liquid solution, suspension or paste that can be sprayed [9, 27]. The product to be dried goes through nozzles of varying sizes, influencing the particle size obtained, the liquid part is transformed into an atomized spray. The dust is carried

Improvement of the physical and chemical characteristics of the materials used in this technique generally involves the comparison of process parameters such as heating, air volume, atomizer nozzle type, flow rate of the material to be dried or atomization system, drying air temperature. Formulation parameters are evaluated together with process parameters. It is important to check, for example, when the temperature is raised, if there is no extensive protein denaturation, loss of flavor, as

Heating and mass transfer during drying occur with air and vapor films around the droplets. This vapor shield keeps the particle at saturation temperature. As the particle does not become dry, evaporation continues, and the temperature of the solids does not approach the temperature of the drying outlet. Because of this,

The shape of most atomized particles is spherical, which ensures fluid-like flow. This helps in the handling and filling process, for example, as well as in reducing costs. The particles still have homogeneity in the composition and the particle size distribution is very close, minimizing the obtaining of very fine particles, which is

Factors such as humidity and water activity are of great importance in the study of the obtained product. Process definition and suitability of equipment operating parameters are particular to each desired finished product, depending on the

As the spray-dryer technique is widely used in the industry, the study of its potentiality and suitability to obtain powder products is a way to study the drying process for this and other products, as well as explore the equipment and its resources, obtaining a differentiated product. Instantization and improving product wettability are very important factors in obtaining a powder product, where the drying technique becomes a means to obtain these characteristics. Straatsma et al. [30] studied the solubility index of spray-dryer instantized materials, and this index is of primary importance for instantized powders. The thermal load of food products during drying is an important factor in the final quality of the powder, since heat exposure can lead to the formation of insoluble materials which are undesirable especially for instant powders. Spray-dryer equipment can be seen in **Figure 4**.

**54**

*Scheme of spray-dryer and drying air flow [31] 1. Air inlet, 2. Heating, 3. Entering the drying chamber, 4. Cyclone, 5. Vacuum Cleaner, 6. Control of inlet air temperature, 7. Control of outlet air temperature and 8. Receiving vessel of final product.*

Optimal selection of inlet and outlet temperature differences is one of the most important aspects of spray-dryer. The outlet temperature cannot be chosen as desired as it results from the combination of inlet temperature - vacuum adjustment and product feed pump performance.

Product feeding and the introduction of the drying air in this type of dryer are performed at the top of the chamber in co-current flow system. Drying takes place while hot air and the product in the form of small droplets travel through the drying chamber to its conical base. Moist air and dry product then follow to the cyclone, where they are separated, and moist air is removed, and the dry powder product is collected at the base of the cyclone.

Atomizing a powder mixture involves a combination of ingredients, improving wettability in water or another liquid, evening out powder particles as well as improving their flowability and dispersibility. Its high cost must be offset by these factors [32].

Dispersibility is the ability of the powder concentrate to suspend in water to form finely divided particles that will remain in suspension for a reasonable period. It is described as a carrier surface feature and dispersing agents are added by overlapping the forces of attraction between the particles [33]. The dispersion of solids is affected by the texture of the powder, and to be instantaneous the powder must be optimal in size and very fine particles should be avoided [19]. Proper formulation requires a balance between aggregate size and interactions between different chemical additives, as well as adjustment of grinding process conditions.

The degree of atomization influences the drying rate, as well as the residence time of the particles influences the drying size. All atomization techniques can provide good control over the average particle size, but there are differences in their distribution [27].

*Powder Technology*

**57**

**Author details**

provided the original work is properly cited.

\*Address all correspondence to: scslan@usp.br

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Suzana Caetano da Silva Lannes\* and Maria Elena Del Dolores Bernal Gómez Department of Biochemical-Pharmaceutical Technology, Pharmaceutical Sciences

School, University of São Paulo - USP, São Paulo, SP, Brazil

*DOI: http://dx.doi.org/10.5772/intechopen.90715*

The concentration of the input product in the atomizer influences the particle size, higher concentration of the solution, the more porous the particles obtained. The lowest concentration provides the smallest and finest particles. Higher flow of atomized product leads to smaller particles in the final product [19]. The adjustment of the process parameters, formulation, atomized product concentration, temperatures, spray speed, should aim at higher yield.

The quality of powdered foods is based on the properties variety that depend on specific applications. In general, final moisture content, solubility, rheological properties of the powder and density are of prime importance. Currently the main challenges in powder production are product development and process cost reduction. As a result, the production capacity is maximized, process conditions are directed to minimal product losses, reduced energy consumption, online quality control [29, 33].

Spray drying is nowadays a technology widely used in the food industry. The purpose is to protect thermosensitive active substances. Many researches are being developed using the microencapsulation method. Thus, to protect oils from lipid oxidation [34–36], incorporating functional ingredients such as vitamins [37, 38], additives and their storage protection [38], antioxidant protection [39].

## **6. Moisture sorption isotherms**

Knowledge of sorption isotherms of powders blend is important for generating data for storage procedures such as shelf life prediction as well as drying processes when this is used in the process. Sorption isotherm can be defined as the graphical representation of the relationship between different humidity and water activity (parameter that describes the degree of binding of water to food particles) at constant temperature [40, 41].

In food, the microscopic structure is of primary importance in all aspects of its functionality. The microscopic organization of both water and other components determines the outcome of macroscopic observations made using different techniques [42–44].

Water activity of a product is defined as the ratio of water vapor pressure to pure water vapor pressure at the same temperature, and the availability of water-based criteria that can provide indicators of stability include water content, solute concentration and osmotic pressure.

## **7. Final considerations**

A perfect mixture of two or more types of solid particles is one in which a sample contains the same proportion of components as any part of the mixture. Mixing of powders is a process that involves a comprehension of the physical elements of the mixture, equipment design, and appropriate sampling technique to ensure mix quality.

*Powder Technology DOI: http://dx.doi.org/10.5772/intechopen.90715*

*Food Processing*

distribution [27].

control [29, 33].

**6. Moisture sorption isotherms**

constant temperature [40, 41].

tration and osmotic pressure.

**7. Final considerations**

techniques [42–44].

The degree of atomization influences the drying rate, as well as the residence time of the particles influences the drying size. All atomization techniques can provide good control over the average particle size, but there are differences in their

The concentration of the input product in the atomizer influences the particle size, higher concentration of the solution, the more porous the particles obtained. The lowest concentration provides the smallest and finest particles. Higher flow of atomized product leads to smaller particles in the final product [19]. The adjustment of the process parameters, formulation, atomized product concentration,

The quality of powdered foods is based on the properties variety that depend on specific applications. In general, final moisture content, solubility, rheological properties of the powder and density are of prime importance. Currently the main challenges in powder production are product development and process cost reduction. As a result, the production capacity is maximized, process conditions are directed to minimal product losses, reduced energy consumption, online quality

Spray drying is nowadays a technology widely used in the food industry. The purpose is to protect thermosensitive active substances. Many researches are being developed using the microencapsulation method. Thus, to protect oils from lipid oxidation [34–36], incorporating functional ingredients such as vitamins [37, 38],

Knowledge of sorption isotherms of powders blend is important for generating data for storage procedures such as shelf life prediction as well as drying processes when this is used in the process. Sorption isotherm can be defined as the graphical representation of the relationship between different humidity and water activity (parameter that describes the degree of binding of water to food particles) at

In food, the microscopic structure is of primary importance in all aspects of its functionality. The microscopic organization of both water and other components determines the outcome of macroscopic observations made using different

Water activity of a product is defined as the ratio of water vapor pressure to pure water vapor pressure at the same temperature, and the availability of water-based criteria that can provide indicators of stability include water content, solute concen-

A perfect mixture of two or more types of solid particles is one in which a sample

contains the same proportion of components as any part of the mixture. Mixing of powders is a process that involves a comprehension of the physical elements of the mixture, equipment design, and appropriate sampling technique to ensure mix

additives and their storage protection [38], antioxidant protection [39].

temperatures, spray speed, should aim at higher yield.

**56**

quality.

## **Author details**

Suzana Caetano da Silva Lannes\* and Maria Elena Del Dolores Bernal Gómez Department of Biochemical-Pharmaceutical Technology, Pharmaceutical Sciences School, University of São Paulo - USP, São Paulo, SP, Brazil

\*Address all correspondence to: scslan@usp.br

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **References**

[1] Zanzoni A, Montecchi-Palazzi L, Quondam MX. Mint: A molecular interaction database. FEBS Letters. 2002;**513**:135-140. DOI: 10.1016/ s0014-5793(01)03293-8

[2] Pernenkil L, Cooney CL. A review on the continuous blending of powders. Chemical Engineering Science. 2006;**61**(2):720-742

[3] Onwulata C. Encapsulated and Powdered Foods. 1st ed. Boca Raton: CRC Press; 2005. p. 528

[4] Fellows PJ. Tecnologia do processamento de alimentos: Princípios e prática. 2.ed. Artmed: Porto Alegre; 2006. p. 602

[5] Singh RP, Heldman DR. Introduction to Food Engineering. 4th ed. Amsterdam: Academic Press; 2009. p. 841. (Food science and technology international series)

[6] Laurent BF, Bridgwater J. Influence of agitator design on powder flow. Chemical Engineering Science. 2002;**57**(18):3781-3793

[7] Barone A, Glassey J, Montague G. Towards online near-infrared spectroscopy to optimize food product mixing. Journal of Food Engineering. 2019;**263**:227-236

[8] Dhanalakshmi K, Ghosal S, Bhattacharya S. Agglomeration of food powder and applications. Critical Reviews in Food Science and Nutrition. 2011;**51**(5):432-441

[9] Lannes SCS, Medeiros ML. Processamento de achocolatado de cupuaçu por spray-dryer. Revista Brasileira de Ciências Farmacêuticas. 2003;**39**(1):115-123

[10] Shittu TA, Lawal MO. Factors affecting instant properties of powdered cocoa beverages. Food Chemistry. 2007;**100**(1):91-98

[11] Medeiros ML. Estudo e aplicação de substitutos de cacau [thesis]. São Paulo: Pharmaceutical Sciences School-University of Sao Paulo; 2006

[12] Teunou E, Fitzpatrick JJ. Effect of relative humidity and temperature on food powder flowability. Journal of Food Engineering. 1999;**42**(2):109-116

[13] Eduardo MF. Avaliação reológica e físico-química de achocolatados e bebidas achocolatadas [thesis]. São Paulo: Pharmaceutical Sciences School-University of Sao Paulo; 2005

[14] Ji J, Fitzpatrick J, Cronin K, Crean A, Miao S. Assessment of measurement characteristics for rehydration of milk protein based powders. Food Hydrocolloids. 2016;**54**:151-161

[15] Shenoy P, Viauc M, Tammel K, Innings F, Fitzpatrick J, Ahrné L. Effect of powder densities, particle size and shape on mixture quality of binary food powder mixtures. Powder Technology. 2015;**272**:165-172

[16] Eduardo MF, Lannes SCS. Use of texture analysis to determine compaction force of powders. Journal of Food Engineering. 2007;**80**:568-572. DOI: 10.1016/j.jfoodeng.2006.06.011

[17] Fitzpatrick JJ, Iqbal T, Delaney C, Twomey T, Keogh MK. Effect of powder properties and storage conditions on the flowability of milk powders with different fat contents. Journal of Food Engineering. 2004;**64**(4):435-444

[18] N'dri-Stempfer B, Oulahna D, Eterradossi O, Dodds JA. The incidence of pressure on the colour of compacted powders. Powder Technology. 2002;**128**(2-3):320-325

**59**

p. 439

*Powder Technology*

1981;**3**(8):29-33

2006;**26**(3):666-671

*DOI: http://dx.doi.org/10.5772/intechopen.90715*

[29] Straatsma J, Van Houwelingen G, Steenbergen AE, De Jong P. Spray drying of food products: 1. Simulation model. Journal of Food Engineering.

[30] Straatsma J, Van Houwelingen G, Steenbergen AE, De Jong P. Spray drying of food products: 2. Prediction of insolubility index. Journal of Food

[31] Büchi Labortechnik AG. Operation Manual – Mini Spray Dryer 190. Flawil;

Characterization of Powders and Fine Particles. London: Heyden; 1980. p. 195

Osemwegie AA. Thermal agglomeration of chocolate drink powder. Journal of Food Engineering. 2000;**46**(2):73-81

[34] Hough G, Sánchez R. Descriptive analysis and external preference mapping of powdered chocolate milk. Food Quality and Preference.

[35] Agibert SAC, Lannes SCS. Dark chocolate added with high oleic peanut oil microcapsule. Journal of the Science of Food and Agriculture. 2018;**98**:5591-

[36] Geranpour M, Emam-Djomeh Z, Asadi G. Investigating the effects of spray drying conditions on the microencapsulation efficiency of pumpkin seed oil. Journal of Food Processing & Preservation.

[37] Haas K, Obernberger J, Zehetner E, Kiesslich A, Volkert M, Jaeger H. Impact

of powder particle structure on the oxidation stability and color of encapsulated crystalline and emulsified carotenoids in carrot concentrate powders. Journal of Food Engineering.

5597. DOI: 10.1002/jsfa.9102

1998;**9**(4):197-204

2019;**43**:13947

2019;**263**:398-408

Engineering. 1999b;**42**:73-77

[32] Beddow JK. Testing and

[33] Omobuwajo TO, Busari OT,

1999a;**42**:67-72

1997-1998

[19] Cartwright B. Spraying provides instant solutions. Food Flavourings, ingredients, Packaging & Processing.

[20] Vissotto FZ, Montenegro FM, Santos JM, Olieira SJR. Avaliação da influência dos processos de lecitinação e de aglomeração nas propriedades físicas de achocolatado em pó. Ciência e Tecnologia de Alimentos.

[21] Barros DJM. Desenho e avaliação de formulações de achocolatados obtidos por processos convencional e instantâneo [thesis]. São Paulo: Pharmaceutical Sciences School-University of Sao Paulo; 2016

[22] Turchiuli C, Gianfrancesco A, Palzer S, Dumoulin E. Evolution of particle properties during spray drying in relation with stickiness and agglomeration control. Powder Technology. 2011;**208**(2):433-440

[23] Wendel S, Celik M. Uma visão geral sobre o uso da tenologia de spraydrying. Pharmaceutical Technology.

[24] Masters KS. Spray Drying in

[25] Sormoli ME, Langrish TAG. Moisture sorption isotherms and net isosteric heat of sorption for spray-dried pure orange juice powder. LWT-Food Science and Technology. 2015;**62**:875-882

ApS: Charlottenlund; 2002

Practice. SprayDryConsult International

[26] Van't Land CM. Industrial Drying Equipment. Selection and Application. New York: Marcel Dekker; 1991. p. 362

[27] Perry RH, Chilton CH. Manual de Engenharia Química. 5th ed. Rio de Janeiro: Guanabara Dois; 1980

[28] Rhodes MJ. Principles of Powder Technology. New York: Wiley; 1990.

1998;**2**(2):129-134

### *Powder Technology DOI: http://dx.doi.org/10.5772/intechopen.90715*

[19] Cartwright B. Spraying provides instant solutions. Food Flavourings, ingredients, Packaging & Processing. 1981;**3**(8):29-33

[20] Vissotto FZ, Montenegro FM, Santos JM, Olieira SJR. Avaliação da influência dos processos de lecitinação e de aglomeração nas propriedades físicas de achocolatado em pó. Ciência e Tecnologia de Alimentos. 2006;**26**(3):666-671

[21] Barros DJM. Desenho e avaliação de formulações de achocolatados obtidos por processos convencional e instantâneo [thesis]. São Paulo: Pharmaceutical Sciences School-University of Sao Paulo; 2016

[22] Turchiuli C, Gianfrancesco A, Palzer S, Dumoulin E. Evolution of particle properties during spray drying in relation with stickiness and agglomeration control. Powder Technology. 2011;**208**(2):433-440

[23] Wendel S, Celik M. Uma visão geral sobre o uso da tenologia de spraydrying. Pharmaceutical Technology. 1998;**2**(2):129-134

[24] Masters KS. Spray Drying in Practice. SprayDryConsult International ApS: Charlottenlund; 2002

[25] Sormoli ME, Langrish TAG. Moisture sorption isotherms and net isosteric heat of sorption for spray-dried pure orange juice powder. LWT-Food Science and Technology. 2015;**62**:875-882

[26] Van't Land CM. Industrial Drying Equipment. Selection and Application. New York: Marcel Dekker; 1991. p. 362

[27] Perry RH, Chilton CH. Manual de Engenharia Química. 5th ed. Rio de Janeiro: Guanabara Dois; 1980

[28] Rhodes MJ. Principles of Powder Technology. New York: Wiley; 1990. p. 439

[29] Straatsma J, Van Houwelingen G, Steenbergen AE, De Jong P. Spray drying of food products: 1. Simulation model. Journal of Food Engineering. 1999a;**42**:67-72

[30] Straatsma J, Van Houwelingen G, Steenbergen AE, De Jong P. Spray drying of food products: 2. Prediction of insolubility index. Journal of Food Engineering. 1999b;**42**:73-77

[31] Büchi Labortechnik AG. Operation Manual – Mini Spray Dryer 190. Flawil; 1997-1998

[32] Beddow JK. Testing and Characterization of Powders and Fine Particles. London: Heyden; 1980. p. 195

[33] Omobuwajo TO, Busari OT, Osemwegie AA. Thermal agglomeration of chocolate drink powder. Journal of Food Engineering. 2000;**46**(2):73-81

[34] Hough G, Sánchez R. Descriptive analysis and external preference mapping of powdered chocolate milk. Food Quality and Preference. 1998;**9**(4):197-204

[35] Agibert SAC, Lannes SCS. Dark chocolate added with high oleic peanut oil microcapsule. Journal of the Science of Food and Agriculture. 2018;**98**:5591- 5597. DOI: 10.1002/jsfa.9102

[36] Geranpour M, Emam-Djomeh Z, Asadi G. Investigating the effects of spray drying conditions on the microencapsulation efficiency of pumpkin seed oil. Journal of Food Processing & Preservation. 2019;**43**:13947

[37] Haas K, Obernberger J, Zehetner E, Kiesslich A, Volkert M, Jaeger H. Impact of powder particle structure on the oxidation stability and color of encapsulated crystalline and emulsified carotenoids in carrot concentrate powders. Journal of Food Engineering. 2019;**263**:398-408

**58**

*Food Processing*

**References**

[1] Zanzoni A, Montecchi-Palazzi L, Quondam MX. Mint: A molecular interaction database. FEBS Letters. 2002;**513**:135-140. DOI: 10.1016/

cocoa beverages. Food Chemistry.

[11] Medeiros ML. Estudo e aplicação de substitutos de cacau [thesis]. São Paulo: Pharmaceutical Sciences School-

[12] Teunou E, Fitzpatrick JJ. Effect of relative humidity and temperature on food powder flowability. Journal of Food Engineering. 1999;**42**(2):109-116

[13] Eduardo MF. Avaliação reológica e físico-química de achocolatados e bebidas achocolatadas [thesis]. São Paulo: Pharmaceutical Sciences School-

[14] Ji J, Fitzpatrick J, Cronin K, Crean A, Miao S. Assessment of measurement characteristics for rehydration of milk protein based powders. Food Hydrocolloids. 2016;**54**:151-161

[15] Shenoy P, Viauc M, Tammel K, Innings F, Fitzpatrick J, Ahrné L. Effect of powder densities, particle size and shape on mixture quality of binary food powder mixtures. Powder Technology.

[16] Eduardo MF, Lannes SCS. Use of texture analysis to determine compaction force of powders. Journal of Food Engineering. 2007;**80**:568-572. DOI: 10.1016/j.jfoodeng.2006.06.011

Delaney C, Twomey T, Keogh MK. Effect of powder properties and storage conditions on the flowability of milk powders with different fat contents. Journal of Food Engineering.

[18] N'dri-Stempfer B, Oulahna D, Eterradossi O, Dodds JA. The incidence of pressure on the colour of compacted

powders. Powder Technology. 2002;**128**(2-3):320-325

[17] Fitzpatrick JJ, Iqbal T,

2004;**64**(4):435-444

2015;**272**:165-172

University of Sao Paulo; 2005

University of Sao Paulo; 2006

2007;**100**(1):91-98

[2] Pernenkil L, Cooney CL. A review on the continuous blending of powders.

Chemical Engineering Science.

[3] Onwulata C. Encapsulated and Powdered Foods. 1st ed. Boca Raton:

processamento de alimentos: Princípios e prática. 2.ed. Artmed: Porto Alegre;

[5] Singh RP, Heldman DR. Introduction

[6] Laurent BF, Bridgwater J. Influence of agitator design on powder flow. Chemical Engineering Science.

[7] Barone A, Glassey J, Montague G. Towards online near-infrared

spectroscopy to optimize food product mixing. Journal of Food Engineering.

Bhattacharya S. Agglomeration of food powder and applications. Critical Reviews in Food Science and Nutrition.

[8] Dhanalakshmi K, Ghosal S,

[9] Lannes SCS, Medeiros ML. Processamento de achocolatado de cupuaçu por spray-dryer. Revista Brasileira de Ciências Farmacêuticas.

[10] Shittu TA, Lawal MO. Factors affecting instant properties of powdered

s0014-5793(01)03293-8

2006;**61**(2):720-742

CRC Press; 2005. p. 528

2006. p. 602

[4] Fellows PJ. Tecnologia do

to Food Engineering. 4th ed. Amsterdam: Academic Press; 2009. p. 841. (Food science and technology

international series)

2002;**57**(18):3781-3793

2019;**263**:227-236

2011;**51**(5):432-441

2003;**39**(1):115-123

[38] Jafari SM, Masoudi S, Akbar B. A Taguchi approach production of spray-dried whey powder enriched with nanoencapcapsulated vitamin D-3. Drying Technology. 2019;**37**(16):2059-2071

[39] Ulas B, Feyza E, Mehmet K. The effect of spray drying conditions on physicochemical properties of encapsulated propolis powder. Journal of Food Process Engineering. 2019;**42**:13024

[40] Labuza TP. Sorption phenomena in foods. Journal of Food Technology. 1968;**22**:263-271

[41] Labuza TP, Hyman CR. Moisture migration and control in multi-domain foods. Trends in Food Science and Technology. 1998;**9**:47-55

[42] Cornilon P, Salim LC. Characterization of water mobility and distribution in low- and intermediatemoisture food systems. Magnetic Resonance Imaging. 2000;**18**(3):335-341

[43] Bensebia O, Allia K. Analysis of adsorption-desorption moisture isotherms of rosemary leaves. Journal of Applied Research on Medicinal and Aromatic Plants. 2016;**3**:79-86

[44] Sormoli ME, Langrish TAG. Spray drying bioactive orange-peel extracts produced by Soxhlet extraction: Use of WPI, antioxidant activity and moisture sorption isotherms. LWT-Food Science and Technology. 2016;**72**:1-8

**61**

**Chapter 4**

*and Kechairi Reda*

**Abstract**

antioxidant

**1. Introduction**

Valorization of the Seeds

(Almonds and Oil) of the

Domesticated Argan of

Mostaganem in Algeria

Spontaneous Argan of Tindouf

and the Other Experimental

*Benaouf Zohra, Djorf Oussama, Jaradat Chawkat* 

ties, which can surely contribute to the safeguarding of the argan tree.

**Keywords:** argan oil, almonds, volatile compounds, parameters, phenolics,

The argan tree, being a xerophile species, observed on the semiarid and arid climate has specific ecological characteristics and many interests (forest, forage, and fruit). Argan oil is essentially rich in unsaturated fatty acids and saturated fatty acids. As for the secondary metabolism, it contains polyphenols, tocopherol, sterol, and alcohol, and this explains its benefits in treating heart diseases and skin infections and in general its therapeutic uses and medication as a food supplement [1, 2]. Argan oil has a high level of oleic and linoleic acids and antioxidant compounds, which has an impact on cardiovascular disease [3]. Minor compounds of argan oil, such as sterols, may be involved in its cholesterol-lowering effect [4]. The antidiabetic effect of argan oil has been claimed for a long time in traditional medicine; however the mechanism of regulation of the level of glucose in the blood remains unknown [5]. The antihypertensive effect of argan oil and its mechanism of action have been studied by Berrougui et al. [6]. The purpose of this present work is the

The aim of the research was to determine the phytochemical and parameters of argan oil and almonds. We are interested in following the formation of volatile compounds in argan oil and also the determination of antioxidants; the purpose was mainly to identify and quantify the antioxidants to meet this objective, two samples of argan oil from the almonds of Tindouf taxa and Mostaganem taxa. The results show that the argan rich in phenolic compounds deserve to be exploited as much as nutritional and pharmaceutical supplements because of their antioxidant proper-

## **Chapter 4**

*Food Processing*

[38] Jafari SM, Masoudi S, Akbar B. A Taguchi approach production of spray-dried whey powder enriched

[39] Ulas B, Feyza E, Mehmet K. The effect of spray drying conditions on physicochemical properties of encapsulated propolis powder. Journal of Food Process Engineering.

[40] Labuza TP. Sorption phenomena in foods. Journal of Food Technology.

[41] Labuza TP, Hyman CR. Moisture migration and control in multi-domain foods. Trends in Food Science and

Characterization of water mobility and distribution in low- and intermediatemoisture food systems. Magnetic Resonance Imaging. 2000;**18**(3):335-341

[43] Bensebia O, Allia K. Analysis of adsorption-desorption moisture isotherms of rosemary leaves. Journal of Applied Research on Medicinal and

Aromatic Plants. 2016;**3**:79-86

and Technology. 2016;**72**:1-8

[44] Sormoli ME, Langrish TAG. Spray drying bioactive orange-peel extracts produced by Soxhlet extraction: Use of WPI, antioxidant activity and moisture sorption isotherms. LWT-Food Science

with nanoencapcapsulated vitamin D-3. Drying Technology.

2019;**37**(16):2059-2071

2019;**42**:13024

1968;**22**:263-271

Technology. 1998;**9**:47-55

[42] Cornilon P, Salim LC.

**60**

Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf and the Other Experimental Domesticated Argan of Mostaganem in Algeria

*Benaouf Zohra, Djorf Oussama, Jaradat Chawkat and Kechairi Reda*

## **Abstract**

The aim of the research was to determine the phytochemical and parameters of argan oil and almonds. We are interested in following the formation of volatile compounds in argan oil and also the determination of antioxidants; the purpose was mainly to identify and quantify the antioxidants to meet this objective, two samples of argan oil from the almonds of Tindouf taxa and Mostaganem taxa. The results show that the argan rich in phenolic compounds deserve to be exploited as much as nutritional and pharmaceutical supplements because of their antioxidant properties, which can surely contribute to the safeguarding of the argan tree.

**Keywords:** argan oil, almonds, volatile compounds, parameters, phenolics, antioxidant

## **1. Introduction**

The argan tree, being a xerophile species, observed on the semiarid and arid climate has specific ecological characteristics and many interests (forest, forage, and fruit). Argan oil is essentially rich in unsaturated fatty acids and saturated fatty acids. As for the secondary metabolism, it contains polyphenols, tocopherol, sterol, and alcohol, and this explains its benefits in treating heart diseases and skin infections and in general its therapeutic uses and medication as a food supplement [1, 2]. Argan oil has a high level of oleic and linoleic acids and antioxidant compounds, which has an impact on cardiovascular disease [3]. Minor compounds of argan oil, such as sterols, may be involved in its cholesterol-lowering effect [4]. The antidiabetic effect of argan oil has been claimed for a long time in traditional medicine; however the mechanism of regulation of the level of glucose in the blood remains unknown [5]. The antihypertensive effect of argan oil and its mechanism of action have been studied by Berrougui et al. [6]. The purpose of this present work is the

**Figure 1.** *Distribution of the argan tree in Tindouf and northwest Africa [7].*

comparison between two provenances of argan tree, an endemic variety that grows in southwestern Tindouf located in Algerian Sahara and the other introduced to Mostaganem located in Mediterranean area (**Figure 1**).

## **2. Materials and methods**

## **2.1 Plant material**

A mature fruit of Algerian argan (*Argania spinosa*) was collected from Tindouf area located in Tindouf and Mostaganem (coastal region) in June 2016; almonds and the extracted oil were analyzed.

**63**

**Table 1.**

**Figure 2.**

*Fruit, seed, and almond argan oil.*

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf…*

sugars were measured according to the method of Dubois et al. [11].

The extraction was carried out by a Soxhlet apparatus, according to the standard technique [8]; the technique consists in using an organic solvent (hexane). 25 g of almond seeds powder are placed in a cartridge, and then the cartridge is closed by cotton and placed in the Soxhlet extractor. A flask is weighed empty and then filled with 200 ml of solvent. This flask is inserted into the extractor and placed in a sand bath set at a boiling point of the solvent. The extraction is carried out for 3 h and 6 h, then the solvent is removed by distillation, and the oil which remains in the flask is dried at a temperature of 105°C for a few minutes. The volatile compounds were extracted by the solid-phase microextraction (SPME) method; this technique does not require the use of solvents or complicated apparatus, and it is based essentially on the adsorption phenomenon based on a balance between the matrix and coating of the fiber. The identification and quantification of aromatic compounds were performed by gas chromatography-mass spectrometry (GC-MS) (**Figure 2**). The chemical parameters were detected according to ISO standards [9, 10]. Total

Equipment related to the results presented in **Table 1:** 50 mg of the almonds of each sample and put in a vial, distilled water is added until at 50 ml. Introduce 1 ml of the solution to be assayed into a tube of each sample and then 1 ml of the phenol solution (5%). The tubes are carefully shaken, and then 5 ml of concentrated

**Parameters Tindouf argan Mostaganem argan** Relative density 0.83 ± 0.02 0.91 ± 0.03 Refractive index 1.4642 ± 0.08 1.4612 ± 0.04 Acid number 2.244 ± 0.01 2.524 ± 0.09 Index saponification 179.55 ± 0.8 185.60 ± 0.5 Ester index 177.306 ± 0.3 183.076 ± 0.5 pH 4.62 ± 0.07 4.43 ± 0.02 Humidity 2 ± 0.001% 4.33 ± 0.002% Phosphatide 11.4 ± 0.06% 13.8 ± 0.02% Extraction yield (3 h) 25.727 ± 0.08% 25.727 ± 0.02% Extraction yield (6 h) 25.727 ± 0.07% 41.67 ± 0.04% Total sugar 8.19 ± 0.04% 4.86 ± 0.06% Fat 38.61 ± 0.3% 41.67 ± 0.5% Ash 2.4 ± 0.03% 1.4 ± 0.01% Nitrogen content 1.045 ± 0.001% 0.602 ± 0.00% Protein 6.53 ± 0.04% 3.76 ± 0.005%

*Chemical and physical parameters of argan oil of two taxa, Tindouf and Mostaganem argan.*

*DOI: http://dx.doi.org/10.5772/intechopen.91655*

**2.2 Argan oil preparation**

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf… DOI: http://dx.doi.org/10.5772/intechopen.91655*

## **2.2 Argan oil preparation**

*Food Processing*

**62**

comparison between two provenances of argan tree, an endemic variety that grows in southwestern Tindouf located in Algerian Sahara and the other introduced to

A mature fruit of Algerian argan (*Argania spinosa*) was collected from Tindouf area located in Tindouf and Mostaganem (coastal region) in June 2016; almonds

Mostaganem located in Mediterranean area (**Figure 1**).

*Distribution of the argan tree in Tindouf and northwest Africa [7].*

**2. Materials and methods**

and the extracted oil were analyzed.

**2.1 Plant material**

**Figure 1.**

The extraction was carried out by a Soxhlet apparatus, according to the standard technique [8]; the technique consists in using an organic solvent (hexane). 25 g of almond seeds powder are placed in a cartridge, and then the cartridge is closed by cotton and placed in the Soxhlet extractor. A flask is weighed empty and then filled with 200 ml of solvent. This flask is inserted into the extractor and placed in a sand bath set at a boiling point of the solvent. The extraction is carried out for 3 h and 6 h, then the solvent is removed by distillation, and the oil which remains in the flask is dried at a temperature of 105°C for a few minutes. The volatile compounds were extracted by the solid-phase microextraction (SPME) method; this technique does not require the use of solvents or complicated apparatus, and it is based essentially on the adsorption phenomenon based on a balance between the matrix and coating of the fiber. The identification and quantification of aromatic compounds were performed by gas chromatography-mass spectrometry (GC-MS) (**Figure 2**).

The chemical parameters were detected according to ISO standards [9, 10]. Total sugars were measured according to the method of Dubois et al. [11].

Equipment related to the results presented in **Table 1:** 50 mg of the almonds of each sample and put in a vial, distilled water is added until at 50 ml. Introduce 1 ml of the solution to be assayed into a tube of each sample and then 1 ml of the phenol solution (5%). The tubes are carefully shaken, and then 5 ml of concentrated

**Figure 2.** *Fruit, seed, and almond argan oil.*


#### **Table 1.**

*Chemical and physical parameters of argan oil of two taxa, Tindouf and Mostaganem argan.*

sulfuric acid "H2SO4" are added using a graduated pipette. After standing for 30 min in the dark, the absorbance (OD) measurements are made at 490 nm in the case of hexoses. The calibration of the spectrophotometer (UV-vis spectrophotometer) is done with a blank solution containing 1 ml of distilled water, 1 ml of 5% phenol, and 5 ml of H2SO4.

The mineral material was determined by 5 g of the almonds of each region placed in the capsules and placed in the muffle furnace with a temperature of 900°C for 2 h and then metered in desiccators until it was cooled and finally weighed. The protein content is carried out in three stages: mineralization, distillation, and titration; in each flask 3 g of sample from each region are introduced, and 1.5 g of the catalyst is added with some glass bead, then 20 ml of sulfuric acid are poured in. A concentrated 50 ml of distilled water and 45 ml of sodium hydroxide solution (40%) are added for 3 min. The end of the apparatus is leveled in a tarpaulin containing 20 ml of boric acid (4%) which fixes the solution. The titration is carried out with a 0.1 N sulfuric acid solution in the presence of a colored indicator (methyl red) until a pink turn is obtained. For the determination of the fat, introduce 50 g of the sample from each region into the cartridge, place it in the Soxhlet, and weigh the empty flask and fill it with hexane (300 ml). After 6 h of extraction, determine the moisture by the loss of sample water (oil), take two capsules, put in each capsule 3 g of the oil, and placed in an oven at a temperature of 105°C for 2 h of drying. For the determination of the refractive index, calibrate the refractometer apparatus with distilled water. Then, one or two drops of each oil sample are placed on the prism, and the dark zone is moved in the middle for the separation cloth of the light and dark beach.

Determination of PH and acid number, 2 g of the sample and introduce it into the flask or flask. Add 5 ml of ethanol and some drops of phenolphthalein solution (or phenol red) as an indicator, and titrate the liquid with the potassium hydroxide solution contained in the burette to the color curve where the volume V is recorded. For the determination of saponification index, in a flask introduce 2 g of the sample, and add with a burette 25 ml of potassium hydroxide solution and fragments of pumice or porcelain. Fit the glass tube or refrigerant, and place the balloon on the boiling water bath. Allow to cool, disassemble the tube, and add 20 ml of water then 5 drops of phenolphthalein solution. The ester number is the number of milligrams of potassium hydroxide necessary for the neutralization of the acids released by the hydrolysis of the esters contained in 1 g of argan oil. Hydrolysis of the esters by heating in the presence of an ethanoic solution, determination of the excess of alkali by a standard solution of hydrochloric acid. For the determination of phosphatide content, introduce 25 g of oil and 200 ml of acetone in a flask, then leave the mixture at a temperature of 4°C for 2 hours, then filter the mixture on the paper previously weighed and dry this paper at a temperature of 100°C up to 150°C, and finally put in the desiccator and weigh.

### *2.2.1 SPME sampling conditions*

Analysis was performed as described by Baccouri et al. [12]. Each oil sample was spiked with 4-methyl-2-pentanone (internal standard) to a final concentration of 6.7 μg/kg. Then 1.5 g was introduced into a 10 ml vial fitted with a silicone septum. The vial was immersed in a water bath at 40°C, and the oily solution is maintained under magnetic stirring. After 2 min, a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber (50/30 μm, 2 cm long from Supelco Ltd., Bellefonte, PA) was exposed to the sample headspace for 30 min [13] and immediately desorbed for 2 min at 260°C in the gas chromatograph in splitless condition. All the analyses were performed in triplicate.

**65**

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf…*

GC-MS analysis was performed with a Shimadzu GC-2010 gas chromatograph equipped with a Shimadzu QP-2010 Plus quadrupole mass spectrometer (Shimadzu Corporation, Kyoto, Japan) and a DB-WAXETR capillary column (30 m × 0.25 mm,

oil) of the identified compounds was calculated by relating the areas of the internal

The amount of total phenolics was assayed spectrophotometrically by means of the modified Folin-Ciocalteu method [14, 15]. Briefly, 2.5 ml of 10-fold diluted Folin-Ciocalteu reagent, 2 ml of 7.5% aqueous sodium carbonate solution, and 0.5 ml of phenolic extract were mixed well. After 15 min of heating at 45°C, the absorbance was measured at 765 nm with a UV-visible spectrophotometer (UV-

The hydrogen-donating ability of the crude extract and radical scavenging activity (RSA) of argan fruit parts were investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging assay (RSA) [17, 18]. All operations were done in the dark or dim light [19]. For control purpose, the absorbance of the

The inhibition percentage (IP) of the DPPH• by the extracts was calculated according the formula IP = [(*A*0min − *A*60min)/*A*0min] × 100. With the percentage of remaining DPPH• being proportional to the antioxidant concentration in the extracts, the DPPH• scavenging activity was expressed as μM of Trolox equivalent

The TAA in crude extracts was determined according to the Trolox equivalent

antioxidant capacity (TEAC) assay following the original analytical procedure described by Re et al. [20] with slight modifications. ABTS radical cation (ABTS•+) was produced by reacting a 7 mM ABTS stock solution with 2.45 mM potassium persulfate (final concentration). For the study, the ABTS•+ stock solution was diluted with ethanol to an absorbance of 0.70 (±0.02) at 734 nm and equilibrated at 30°C. Sample solutions of 30 μL (or standard) were mixed with ABTS•+ solution 3 ml. Absorbance readings were taken at 30°C exactly 6 min after initial mixing. An appropriate solvent blank was obtained by mixing an absolute ethanol of 30 μL with ABTS•+ solution of 3 ml and monitored its absorbance at 6 min. All determinations were carried out in triplicate. The ABTS•+ scavenging

of

0.25 mm film thickness, J&W Scientific Inc., Folsom, CA, USA). Due to the high boiling point of the oily compounds, direct injection to GC-MS apparatus is impossible, and pre-preparation has to be done. We used increased temperatures. Detection was carried out by electron impact mass spectrometry in total ion current (TIC) mode, using ionization energy of 70 eV. The identification of volatile compounds was confirmed by the injection of pure standards. Compounds for which pure standards were not available were identified on the basis of mass spectra and retention indices available in the literature. The relative concentration (μg kg<sup>−</sup><sup>1</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.91655*

*2.2.2 GC-MS analysis*

standard of each compound.

**2.3 Spectrophotometric assays**

*2.3.1 Determination of total phenolic content (TPC)*

1700 Pharmaspec, Shimadzu, Milan, Italy) [16].

DPPH• without samples was measured.

*2.3.3 Determination of total antioxidant activity (TAA)*

(TE) per mg of sample.

*2.3.2 Determination of DPPH radical scavenging activity (RSA)*

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf… DOI: http://dx.doi.org/10.5772/intechopen.91655*

### *2.2.2 GC-MS analysis*

*Food Processing*

and dark beach.

and finally put in the desiccator and weigh.

All the analyses were performed in triplicate.

*2.2.1 SPME sampling conditions*

phenol, and 5 ml of H2SO4.

sulfuric acid "H2SO4" are added using a graduated pipette. After standing for 30 min in the dark, the absorbance (OD) measurements are made at 490 nm in the case of hexoses. The calibration of the spectrophotometer (UV-vis spectrophotometer) is done with a blank solution containing 1 ml of distilled water, 1 ml of 5%

The mineral material was determined by 5 g of the almonds of each region placed in the capsules and placed in the muffle furnace with a temperature of 900°C for 2 h and then metered in desiccators until it was cooled and finally weighed. The protein content is carried out in three stages: mineralization, distillation, and titration; in each flask 3 g of sample from each region are introduced, and 1.5 g of the catalyst is added with some glass bead, then 20 ml of sulfuric acid are poured in. A concentrated 50 ml of distilled water and 45 ml of sodium hydroxide solution (40%) are added for 3 min. The end of the apparatus is leveled in a tarpaulin containing 20 ml of boric acid (4%) which fixes the solution. The titration is carried out with a 0.1 N sulfuric acid solution in the presence of a colored indicator (methyl red) until a pink turn is obtained. For the determination of the fat, introduce 50 g of the sample from each region into the cartridge, place it in the Soxhlet, and weigh the empty flask and fill it with hexane (300 ml). After 6 h of extraction, determine the moisture by the loss of sample water (oil), take two capsules, put in each capsule 3 g of the oil, and placed in an oven at a temperature of 105°C for 2 h of drying. For the determination of the refractive index, calibrate the refractometer apparatus with distilled water. Then, one or two drops of each oil sample are placed on the prism, and the dark zone is moved in the middle for the separation cloth of the light

Determination of PH and acid number, 2 g of the sample and introduce it into the flask or flask. Add 5 ml of ethanol and some drops of phenolphthalein solution (or phenol red) as an indicator, and titrate the liquid with the potassium hydroxide solution contained in the burette to the color curve where the volume V is recorded. For the determination of saponification index, in a flask introduce 2 g of the sample, and add with a burette 25 ml of potassium hydroxide solution and fragments of pumice or porcelain. Fit the glass tube or refrigerant, and place the balloon on the boiling water bath. Allow to cool, disassemble the tube, and add 20 ml of water then 5 drops of phenolphthalein solution. The ester number is the number of milligrams of potassium hydroxide necessary for the neutralization of the acids released by the hydrolysis of the esters contained in 1 g of argan oil. Hydrolysis of the esters by heating in the presence of an ethanoic solution, determination of the excess of alkali by a standard solution of hydrochloric acid. For the determination of phosphatide content, introduce 25 g of oil and 200 ml of acetone in a flask, then leave the mixture at a temperature of 4°C for 2 hours, then filter the mixture on the paper previously weighed and dry this paper at a temperature of 100°C up to 150°C,

Analysis was performed as described by Baccouri et al. [12]. Each oil sample was spiked with 4-methyl-2-pentanone (internal standard) to a final concentration of 6.7 μg/kg. Then 1.5 g was introduced into a 10 ml vial fitted with a silicone septum. The vial was immersed in a water bath at 40°C, and the oily solution is maintained under magnetic stirring. After 2 min, a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber (50/30 μm, 2 cm long from Supelco Ltd., Bellefonte, PA) was exposed to the sample headspace for 30 min [13] and immediately desorbed for 2 min at 260°C in the gas chromatograph in splitless condition.

**64**

GC-MS analysis was performed with a Shimadzu GC-2010 gas chromatograph equipped with a Shimadzu QP-2010 Plus quadrupole mass spectrometer (Shimadzu Corporation, Kyoto, Japan) and a DB-WAXETR capillary column (30 m × 0.25 mm, 0.25 mm film thickness, J&W Scientific Inc., Folsom, CA, USA). Due to the high boiling point of the oily compounds, direct injection to GC-MS apparatus is impossible, and pre-preparation has to be done. We used increased temperatures. Detection was carried out by electron impact mass spectrometry in total ion current (TIC) mode, using ionization energy of 70 eV. The identification of volatile compounds was confirmed by the injection of pure standards. Compounds for which pure standards were not available were identified on the basis of mass spectra and retention indices available in the literature. The relative concentration (μg kg<sup>−</sup><sup>1</sup> of oil) of the identified compounds was calculated by relating the areas of the internal standard of each compound.

## **2.3 Spectrophotometric assays**

## *2.3.1 Determination of total phenolic content (TPC)*

The amount of total phenolics was assayed spectrophotometrically by means of the modified Folin-Ciocalteu method [14, 15]. Briefly, 2.5 ml of 10-fold diluted Folin-Ciocalteu reagent, 2 ml of 7.5% aqueous sodium carbonate solution, and 0.5 ml of phenolic extract were mixed well. After 15 min of heating at 45°C, the absorbance was measured at 765 nm with a UV-visible spectrophotometer (UV-1700 Pharmaspec, Shimadzu, Milan, Italy) [16].

### *2.3.2 Determination of DPPH radical scavenging activity (RSA)*

The hydrogen-donating ability of the crude extract and radical scavenging activity (RSA) of argan fruit parts were investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging assay (RSA) [17, 18]. All operations were done in the dark or dim light [19]. For control purpose, the absorbance of the DPPH• without samples was measured.

The inhibition percentage (IP) of the DPPH• by the extracts was calculated according the formula IP = [(*A*0min − *A*60min)/*A*0min] × 100. With the percentage of remaining DPPH• being proportional to the antioxidant concentration in the extracts, the DPPH• scavenging activity was expressed as μM of Trolox equivalent (TE) per mg of sample.

#### *2.3.3 Determination of total antioxidant activity (TAA)*

The TAA in crude extracts was determined according to the Trolox equivalent antioxidant capacity (TEAC) assay following the original analytical procedure described by Re et al. [20] with slight modifications. ABTS radical cation (ABTS•+) was produced by reacting a 7 mM ABTS stock solution with 2.45 mM potassium persulfate (final concentration). For the study, the ABTS•+ stock solution was diluted with ethanol to an absorbance of 0.70 (±0.02) at 734 nm and equilibrated at 30°C. Sample solutions of 30 μL (or standard) were mixed with ABTS•+ solution 3 ml. Absorbance readings were taken at 30°C exactly 6 min after initial mixing. An appropriate solvent blank was obtained by mixing an absolute ethanol of 30 μL with ABTS•+ solution of 3 ml and monitored its absorbance at 6 min. All determinations were carried out in triplicate. The ABTS•+ scavenging

effect (% Inhibition) was calculated by the equation % Inhibition = [(*A*734blank × *A*734sample)/*A*734blank] × 100 where *A*734blank and *A*734sample are the absorbances of ABTS•+ solution at 734 nm before and after the sample addition. Calibration was performed, as described previously, with Trolox stock solutions. Results were expressed as μM Trolox equivalent (TE) per mg of sample.

## **2.4 Statistical analysis**

Significant differences among different oils were tested by the one-way analysis of variance and the Duncan test for mean comparison. Statistical analyses were performed using the software package Statistica version 7. Results were reported as mean ± standard deviation (*n* = 3). The analysis of variance (one-way ANOVA) was performed with SPSS software (version 12.0 for Windows, SPSS Inc., Chicago, Illinois). Duncan's test was applied to assess significant differences among the variables (*p* < 0.05), while Pearson correlation test was used to show their correlations.

## **3. Results and discussion**

We noted a small difference in the extraction yield of almonds for both Tindouf and Mostaganem taxa, respectively (25.727–29.272%), after the 3 h duration, while they have a difference of 38.63–41.67% for the duration of 6 h. The percentages of the total sugar of Mostaganem taxa kernels (4.86%) are equal to almost half of the percentage of Tindouf taxa total sugars (8.19%). The sample of Tindouf taxa kernels contains a significant ash (2.4%) compared to the Mostaganem taxa sample (1.4%). The protein content of Tindouf almonds (6.35%) is high compared to the Mostaganem taxa (3.76%). As for the amount of fat, it is brought closer together between the two samples; the kernel gives a significant amount of (40%). Concerning the physicochemical characteristics of argan oil, according to our results we notice that argan oil is not miscible with ethanol for both samples. A difference in the moisture content between the argan oil of the Mostaganem taxa (4.33%) and the Tindouf taxa (2%), and the relative density, by comparison the Tindouf oil (0.83) is lower than Mostaganem (0.91). On the other hand, for the refractive index of argan oil, we record the same values 1.46) with an acid pH. Regarding the other indices, the acidity index of the oil of Mostaganem taxa is equal to 2.5245 and that of Tindouf is 2.2440; the saponification index of the oil of Mostaganem is 185.6 and that of Tindouf is 179.55 (**Table 2**).

The results show some volatile compounds, including compounds of lipid peroxidation, Strecker degradation, and Maillard reaction, responsible for the formation of pyrazines and autoxidation of fatty acids. This study could help to adjust the argan oil aroma and perhaps meet new types of consumers. For the phytochemical part, we have undertaken a study on the volatile composition of argan oil. Extraction of the volatile compounds was carried out by solid-phase microextraction (SPME), and their identification and quantification were performed by gas chromatography-mass spectrometry (GC-MS). Finally, we were interested in the elucidation and quantification of polyphenols. These secondary metabolites are of great importance because of their antioxidant properties. In total, 11 phenolic compounds were identified and quantified in the argan tree. This could be achieved through the coupling of liquid chromatography and electrospray negative ion mass spectrometry (LC-ESI-MS). Among the polyphenols cited are procyanidins B1 and B2, (+)-catechin, (−)-epigallocatechin gallate, (−)-epicatechin, isoquercitrin, hyperoside, rutin, phloridzin, myricetin, and quercitrin. The unroasted kernels and the shell are characterized by a diverse phenolic composition. The pulp is

**67**

**Table 2.**

*\* p < 0.05. \*\*p < 0.01. \*\*\*p < 0.001.*

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf…*

**Compound Tindouf argan Mostaganem argan** *p*

Butanoic 1.2 ± 0.2d 1.5 ± 0.5d \*\* Valeric 1.2 ± 0.3b 1.5 ± 0.2d \*\*\* Hexanoic 5.2 ± 1.5b 4.9 ± 2.6b \*\*

1-Butanol 1.6 ± 0.02 1.5 ± 0.43 ns 1-Pentanol 7.5 ± 0.4b 11.6 ± 2.4c \*\*\* 1-Hexanol 20.8 ± 1.5 20.5 ± 2.6 ns 2-Heptanol 0.7 ± 0.1a 1.1 ± 0.4a \*\*\* 2,3-Butanediol *d,l* 40.2 ± 4.3 34.3 ± 5.2 ns

Hexanal 26.1 ± 0.8b 28.9 ± 5.89 \*\*\* Benzaldehyde 1.2 ± 0.1bc 1.4 ± 0.9c \*\*\*

Ethyl 2-methyl butanoate 0.1 ± 0.01ab 0.1 ± 0.03a \*\*\* *i-Amyl acetate* 1.2 ± 0.03c 0.8 ± 0.4c \*\* μ-Butyrolactone 2.2 ± 0.6c 3.6 ± 1.2c \*\*

2-Heptanone 5.2 ± 0.4b 4.8 ± 1.2c \*\*\* Acetoin 5.4 ± 0.8ab 4.2 ± 1.4ab \*\*\* 2-Undecanone 4.2 ± 0.2ab 3.1 ± 0.6ab \*\*\*

Limonene 0.3 ± 0.4a 0.25 ± 0.6b \*\*

1-Methyl-*1H*-pyrrol 158.4 ± 22.1a μg/kg 147.1 ± 15.8b \*\* 2-Methyl pyrazine 121.3 ± 34.0ab 138.2 ± 36.5c \*\*\* 2,6-Dimethyl pyrazine 263.4 ± 42bc 273.1 ± 40.8d \*\* 2,3-Dimethyl pyrazine 6.3 ± 0.1ab 7.5 ± 0.9c \*\* 2-Ethyl-5-methyl pyrazine 24.9 ± 1.5a 23.4 ± 1.6c \*\*\* 2-Ethyl-6-methyl pyrazine 35.3 ± 4.2b 37.5 ± 3.2c \*\*\* Trimethyl pyrazine 26.4 ± 1.2bc 49.8 ± 3.2d \*\*\* 2-Ethyl-3,5-dimethyl pyrazine 26.9 ± 0.5c 33.2 ± 0.9d \*\*\*

2-Pentyl furan 23.1 ± 0.5ab 22.5 ± 5.8b \* Furfurol 72.3 ± 1.0a 85.4 ± 4.4b \*\*\* 2-Furanmethanol 12.6 ± 0.7b 14.5 ± 2c \*\*\* *q, quantifier ion. Different letters in the same row at mean concentration values indicate significant differences* 

*Quantified volatile compounds (μg/kg of oil ± SD) isolated in argan oil of two taxa.*

*DOI: http://dx.doi.org/10.5772/intechopen.91655*

*Acids*

*Alcohols*

*Aldehydes*

*Esters, lactones*

*Ketones*

*Terpene*

*Furans*

*N-heterocycle* μg/kg (it is not %)

*(p < 0.05) as analyzed by Duncan test.*


*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf… DOI: http://dx.doi.org/10.5772/intechopen.91655*

*q, quantifier ion. Different letters in the same row at mean concentration values indicate significant differences (p < 0.05) as analyzed by Duncan test.*

*\* p < 0.05.*

*Food Processing*

**2.4 Statistical analysis**

**3. Results and discussion**

effect (% Inhibition) was calculated by the equation % Inhibition = [(*A*734blank × *A*734sample)/*A*734blank] × 100 where *A*734blank and *A*734sample are the absorbances of ABTS•+ solution at 734 nm before and after the sample addition. Calibration was performed, as described previously, with Trolox stock solutions.

Significant differences among different oils were tested by the one-way analysis of variance and the Duncan test for mean comparison. Statistical analyses were performed using the software package Statistica version 7. Results were reported as mean ± standard deviation (*n* = 3). The analysis of variance (one-way ANOVA) was performed with SPSS software (version 12.0 for Windows, SPSS Inc., Chicago, Illinois). Duncan's test was applied to assess significant differences among the variables (*p* < 0.05), while Pearson correlation test was used to show their correlations.

We noted a small difference in the extraction yield of almonds for both Tindouf and Mostaganem taxa, respectively (25.727–29.272%), after the 3 h duration, while they have a difference of 38.63–41.67% for the duration of 6 h. The percentages of the total sugar of Mostaganem taxa kernels (4.86%) are equal to almost half of the percentage of Tindouf taxa total sugars (8.19%). The sample of Tindouf taxa kernels contains a significant ash (2.4%) compared to the Mostaganem taxa sample (1.4%). The protein content of Tindouf almonds (6.35%) is high compared to the Mostaganem taxa (3.76%). As for the amount of fat, it is brought closer together between the two samples; the kernel gives a significant amount of (40%). Concerning the physicochemical characteristics of argan oil, according to our results we notice that argan oil is not miscible with ethanol for both samples. A difference in the moisture content between the argan oil of the Mostaganem taxa (4.33%) and the Tindouf taxa (2%), and the relative density, by comparison the Tindouf oil (0.83) is lower than Mostaganem (0.91). On the other hand, for the refractive index of argan oil, we record the same values 1.46) with an acid pH. Regarding the other indices, the acidity index of the oil of Mostaganem taxa is equal to 2.5245 and that of Tindouf is 2.2440; the saponification index of the oil of

Mostaganem is 185.6 and that of Tindouf is 179.55 (**Table 2**).

The results show some volatile compounds, including compounds of lipid peroxidation, Strecker degradation, and Maillard reaction, responsible for the formation of pyrazines and autoxidation of fatty acids. This study could help to adjust the argan oil aroma and perhaps meet new types of consumers. For the phytochemical part, we have undertaken a study on the volatile composition of argan oil. Extraction of the volatile compounds was carried out by solid-phase microextraction (SPME), and their identification and quantification were performed by gas chromatography-mass spectrometry (GC-MS). Finally, we were interested in the elucidation and quantification of polyphenols. These secondary metabolites are of great importance because of their antioxidant properties. In total, 11 phenolic compounds were identified and quantified in the argan tree. This could be achieved through the coupling of liquid chromatography and electrospray negative ion mass spectrometry (LC-ESI-MS). Among the polyphenols cited are procyanidins B1 and B2, (+)-catechin, (−)-epigallocatechin gallate, (−)-epicatechin, isoquercitrin, hyperoside, rutin, phloridzin, myricetin, and quercitrin. The unroasted kernels and the shell are characterized by a diverse phenolic composition. The pulp is

Results were expressed as μM Trolox equivalent (TE) per mg of sample.

**66**

*\*\*p < 0.01. \*\*\*p < 0.001.*

#### **Table 2.**

*Quantified volatile compounds (μg/kg of oil ± SD) isolated in argan oil of two taxa.*

quantitatively rich in total polyphenols (69.53 mg gallic acid equivalent/g). It showed a free radical scavenging activity, measured by DPPH. Important relative to other parts of the fruit (0.12 ± 0.004 μM Trolox equivalents/mg) and antioxidant activity (ABTS•+) (0.287 ± 0.05 μM equivalent/mg Trolox). Interestingly, the results obtained confirm that argan fruit polyphenols deserve to be exploited as much as nutritional and pharmaceutical supplements because of their antioxidant properties, which can surely contribute to the safeguarding of the argan tree. The aim of this work was to identify and quantify the phenolic compounds of argan fruit and by-products of argan oil extraction. Total phenolic content and antioxidant activity by DPPH and ABTS were evaluated. The LC-MS examination resulted in the detection of 10 compounds of which 8 were unambiguously identified. The identified compounds are classified into three groups: flavanols, flavonols, and dihydrochalcones. The results showed that six compounds were detected in the pulp: isoquercitrin and hyperoside are predominant (25.8 and 18.5 mg/100 g, respectively); they are followed by rutin (7.2 mg/100 g) and quercitrin (0.32 mg/100 g). Epicatechin and procyanidin B2 were also detected but could not be quantified. The phenolic compounds of the fruit shell of the argan tree have not been the subject of any prior work. The major phenolic compound isolated from the shell is (−)-epicatechin (0.45 mg/100 g), followed by isoquercitrin (0.32 mg/100 g). Rutin and phloridzin have the same level (0.18 mg/100 g), hyperoside and procyanidins B1 and B2 both 0.08 mg/100 g, myricetin 0.04 mg/100 g, and finally the quercitrin that was detected could not be quantified. As for kernels and meal, a major compound was detected; however this compound could not be identified by Tandem mass spectrometry (Mw = 423.5, Rt: 8.5 min).

## **4. Conclusion**

The average oil density of Mostaganem taxa seems low compared to Tindouf oil. For the refractive index, a small difference is noted between the two taxa of *Argania spinosa* oil. For the acid index, the sample of the Mostaganem area seems to be richer in free fatty acids than in the Tindouf area. Same for the saponification index and the ester index, it is important in the argan oil of Mostaganem than Tindouf. For the phosphatide content, it seems high in both zones, but Mostaganem oil is richer. Also our results show that the phenolic fractions studied have remarkable antioxidant properties. Although the composition of the phenolic fraction of fruits can evolve over the years, they deserve a better valuation in the pharmacological, cosmetic, and agro-food fields because of their antioxidant properties.

**69**

**Author details**

Algeria

Benaouf Zohra1,2\*, Djorf Oussama3,4, Jaradat Chawkat5

University of Mustapha Stambouli, Mascara, Algeria

5 Research Laboratory on Biological, El Khalil, Palestine

\*Address all correspondence to: zohrabenaouf@gmail.com

USTHB University, Algiers, Algeria

4 Laboratory of Ecology, Algeria

Tlemcen University, Tlemcen, Algeria

1 Research Laboratory in Geo Environment and Spatial Development LGEDE,

2 Laboratory of Plant Ecology and Environment, Faculty of Biological Sciences,

3 Laboratory of Biochemistry, Faculty of Chemistry, USTHB University, Algiers,

6 Laboratory of Plant Ecology and Environment, Faculty of Biological Sciences,

provided the original work is properly cited.

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf…*

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

and Kechairi Reda6

*DOI: http://dx.doi.org/10.5772/intechopen.91655*

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf… DOI: http://dx.doi.org/10.5772/intechopen.91655*

## **Author details**

*Food Processing*

**4. Conclusion**

quantitatively rich in total polyphenols (69.53 mg gallic acid equivalent/g). It showed a free radical scavenging activity, measured by DPPH. Important relative to other parts of the fruit (0.12 ± 0.004 μM Trolox equivalents/mg) and antioxidant activity (ABTS•+) (0.287 ± 0.05 μM equivalent/mg Trolox). Interestingly, the results obtained confirm that argan fruit polyphenols deserve to be exploited as much as nutritional and pharmaceutical supplements because of their antioxidant properties, which can surely contribute to the safeguarding of the argan tree. The aim of this work was to identify and quantify the phenolic compounds of argan fruit and by-products of argan oil extraction. Total phenolic content and antioxidant activity by DPPH and ABTS were evaluated. The LC-MS examination resulted in the detection of 10 compounds of which 8 were unambiguously identified. The identified compounds are classified into three groups: flavanols, flavonols, and dihydrochalcones. The results showed that six compounds were detected in the pulp: isoquercitrin and hyperoside are predominant (25.8 and 18.5 mg/100 g,

respectively); they are followed by rutin (7.2 mg/100 g) and quercitrin

Tandem mass spectrometry (Mw = 423.5, Rt: 8.5 min).

and agro-food fields because of their antioxidant properties.

(0.32 mg/100 g). Epicatechin and procyanidin B2 were also detected but could not be quantified. The phenolic compounds of the fruit shell of the argan tree have not been the subject of any prior work. The major phenolic compound isolated from the shell is (−)-epicatechin (0.45 mg/100 g), followed by isoquercitrin (0.32 mg/100 g). Rutin and phloridzin have the same level (0.18 mg/100 g), hyperoside and procyanidins B1 and B2 both 0.08 mg/100 g, myricetin 0.04 mg/100 g, and finally the quercitrin that was detected could not be quantified. As for kernels and meal, a major compound was detected; however this compound could not be identified by

The average oil density of Mostaganem taxa seems low compared to Tindouf oil. For the refractive index, a small difference is noted between the two taxa of *Argania spinosa* oil. For the acid index, the sample of the Mostaganem area seems to be richer in free fatty acids than in the Tindouf area. Same for the saponification index and the ester index, it is important in the argan oil of Mostaganem than Tindouf. For the phosphatide content, it seems high in both zones, but Mostaganem oil is richer. Also our results show that the phenolic fractions studied have remarkable antioxidant properties. Although the composition of the phenolic fraction of fruits can evolve over the years, they deserve a better valuation in the pharmacological, cosmetic,

**68**

Benaouf Zohra1,2\*, Djorf Oussama3,4, Jaradat Chawkat5 and Kechairi Reda6

1 Research Laboratory in Geo Environment and Spatial Development LGEDE, University of Mustapha Stambouli, Mascara, Algeria

2 Laboratory of Plant Ecology and Environment, Faculty of Biological Sciences, USTHB University, Algiers, Algeria

3 Laboratory of Biochemistry, Faculty of Chemistry, USTHB University, Algiers, Algeria

4 Laboratory of Ecology, Algeria

5 Research Laboratory on Biological, El Khalil, Palestine

6 Laboratory of Plant Ecology and Environment, Faculty of Biological Sciences, Tlemcen University, Tlemcen, Algeria

\*Address all correspondence to: zohrabenaouf@gmail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **References**

[1] Hilali M, Charrouf Z, Soulhi AEA, Hachimi L, Guillaume D. Influence of origin and extraction method on argan oil physicochemical characteristics and composition. Journal of Agricultural and Food Chemistry. 2005;**53**:2081-2087

[2] Harhar H, Gharby S, Kartah B, El Monfalouti H, Guillaume D, Charrouf Z. Influence of argan kernel roasting-time on virgin argan oil composition and oxidative stability. Plant Food for Human Nutrition. 2011;**66**:163-168

[3] Derouiche A, Cherki M, Drissi A, Bamou Y, El Messal AM, Idrissi-Oudghiri A, et al. Nutritional intervention study with argan oil in man: Effects on lipids and apolipoproteins. Annals of Nutrition and Metabolism. 2005;**49**:196-201

[4] Khallouki F et al. Consumption of argan oil (Morocco) with its unique profile of fatty acids, tocopherols, squalene, sterols and phenolic compounds should confer valuable cancer chemopreventive effects. European Journal of Cancer Prevention. 2003;**12**:67-75

[5] Emonard H et al. Inhibition of gelatinase A by oleic acid. Annals of the New York Academy of Sciences. 1999;**878**:647-649

[6] Berrougui H, Alvarez de Sotomayor M, Perz-Guerrero C, Attaib A, Hmamouchi M, Marhuenda ER, et al. Argan (Argania spinosa) oil lowers blood pressure and improves endothelial dysfunction in spontaneously hypertensive rats. The British Journal of Nutrition. 2004;**92**:921-929

[7] Kechairi R, Abdoun F. Cartographic status of the argan tree *Argania spinosa* (L.) Skeels (Sapotaceae) in North-West Africa (Algeria and Western Sahara).

International Journal of Environmental Studies. 2016;**73**:286-293

[8] Afnor. Compendium of French Standards on Fats, Oilseeds, Derived Products. 4th ed. Paris: French Association of Standardization; 1988

[9] ISO-6886. Animal and vegetable fats oils-determination of oxidative stability (accelerated oxidations test). 1989

[10] ISO 659. Oilseeds-Determination of oil content (reference method). 2009

[11] Dubois M et al. Colorimetric method for determination of suger and related substances. Analytical Chemistry. 1956:23-38

[12] Baccouri O, Bendini A, Cerretani L, Guerfel M, Baccouri B, Lercker G, et al. Comparative study on volatile compounds from Tunisian and Sicilian monovarietal virgin olive oils. Food Chemistry. 2008;**111**:322-328

[13] Naczk N, Shahidi F. Phenolics in cereals, fruits and vegetables: Occurrence, extraction and analysis. Journal of Pharmaceutical and Biomedical Analysis. 2006;**41**:1523-1542

[14] Singleton VL, Rossi JA. Colorimetry of total phenolics with phosphomolybdic phosphotungstic acid reagents. American Journal of Enology and Viticulture. 1965;**16**:144-158

[15] Singleton VL, Orthofer R, Lamuela-Raventos RM. Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Methods in Enzymology. 1999;**299**:152-178

[16] Pinelo M, Rubilar M, Jerez M, Sineiro J, Núñez MJ. Effect of solvent, temperature and solvent-to-solid ratio on the total phenolic content and

**71**

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf…*

*DOI: http://dx.doi.org/10.5772/intechopen.91655*

antiradicalary activity of extracts from different components of grape pomace. Journal of Agricultural and Food Chemistry. 2005;**53**:2111-2117

[17] Von Gadow A, Joubert E, Hansmann CF. Comparison of the antioxidant activity of aspalathin with that of other plant phenols of Rooibosed tea (*Aspalathus linearis*), α-tocopherol, BHT and BHA. Journal of Agricultural and Food Chemistry. 1997;**45**:632-638

[18] Schinella SM, Cienfuegos-

Ramón D, Ríos JL. Antioxidant properties of polyphenol-rich cocoa products industrially processed. Food Research International.

[19] Sharma OP, Bhat TK. DPPH antioxidant assay revisited. Food Chemistry. 2009;**113**:1202-1205

[20] Re R, Pellegrini N, Proteggente A, Pannala A, Yang M, Rice-Evans C. Antioxidant activity applying an improved ABTS radical cation decolourization assay. Free Radical Biology and Medicine. 1999;**26**:1231-1237

2010;**43**:1614-1623

Jovellanos E, Pasamar MA, Muguerza B,

*Valorization of the Seeds (Almonds and Oil) of the Spontaneous Argan of Tindouf… DOI: http://dx.doi.org/10.5772/intechopen.91655*

antiradicalary activity of extracts from different components of grape pomace. Journal of Agricultural and Food Chemistry. 2005;**53**:2111-2117

[17] Von Gadow A, Joubert E, Hansmann CF. Comparison of the antioxidant activity of aspalathin with that of other plant phenols of Rooibosed tea (*Aspalathus linearis*), α-tocopherol, BHT and BHA. Journal of Agricultural and Food Chemistry. 1997;**45**:632-638

[18] Schinella SM, Cienfuegos-Jovellanos E, Pasamar MA, Muguerza B, Ramón D, Ríos JL. Antioxidant properties of polyphenol-rich cocoa products industrially processed. Food Research International. 2010;**43**:1614-1623

[19] Sharma OP, Bhat TK. DPPH antioxidant assay revisited. Food Chemistry. 2009;**113**:1202-1205

[20] Re R, Pellegrini N, Proteggente A, Pannala A, Yang M, Rice-Evans C. Antioxidant activity applying an improved ABTS radical cation decolourization assay. Free Radical Biology and Medicine. 1999;**26**:1231-1237

**70**

*Food Processing*

**References**

2011;**66**:163-168

2003;**12**:67-75

1999;**878**:647-649

[3] Derouiche A, Cherki M, Drissi A, Bamou Y, El Messal AM, Idrissi-Oudghiri A, et al. Nutritional intervention study with argan oil in man: Effects on lipids and apolipoproteins. Annals of Nutrition and Metabolism. 2005;**49**:196-201

[4] Khallouki F et al. Consumption of argan oil (Morocco) with its unique profile of fatty acids, tocopherols, squalene, sterols and phenolic compounds should confer valuable cancer chemopreventive effects.

European Journal of Cancer Prevention.

Sotomayor M, Perz-Guerrero C, Attaib A, Hmamouchi M, Marhuenda ER, et al. Argan (Argania spinosa) oil lowers blood pressure and improves endothelial

hypertensive rats. The British Journal of

[7] Kechairi R, Abdoun F. Cartographic status of the argan tree *Argania spinosa* (L.) Skeels (Sapotaceae) in North-West Africa (Algeria and Western Sahara).

[5] Emonard H et al. Inhibition of gelatinase A by oleic acid. Annals of the New York Academy of Sciences.

[6] Berrougui H, Alvarez de

dysfunction in spontaneously

Nutrition. 2004;**92**:921-929

[1] Hilali M, Charrouf Z, Soulhi AEA, Hachimi L, Guillaume D. Influence of origin and extraction method on argan oil physicochemical characteristics and composition. Journal of Agricultural and Food Chemistry. 2005;**53**:2081-2087 International Journal of Environmental

[9] ISO-6886. Animal and vegetable fats oils-determination of oxidative stability (accelerated oxidations test). 1989

[10] ISO 659. Oilseeds-Determination of oil content (reference method). 2009

[12] Baccouri O, Bendini A, Cerretani L, Guerfel M, Baccouri B, Lercker G, et al. Comparative study on volatile compounds from Tunisian and Sicilian monovarietal virgin olive oils. Food Chemistry. 2008;**111**:322-328

[13] Naczk N, Shahidi F. Phenolics in cereals, fruits and vegetables: Occurrence, extraction and analysis. Journal of Pharmaceutical and

Biomedical Analysis. 2006;**41**:1523-1542

[14] Singleton VL, Rossi JA. Colorimetry of total phenolics with phosphomolybdic

phosphotungstic acid reagents. American Journal of Enology and Viticulture. 1965;**16**:144-158

[15] Singleton VL, Orthofer R, Lamuela-Raventos RM. Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Methods in

Enzymology. 1999;**299**:152-178

[16] Pinelo M, Rubilar M, Jerez M, Sineiro J, Núñez MJ. Effect of solvent, temperature and solvent-to-solid ratio on the total phenolic content and

[11] Dubois M et al. Colorimetric method for determination of suger and related substances. Analytical

Chemistry. 1956:23-38

[8] Afnor. Compendium of French Standards on Fats, Oilseeds, Derived Products. 4th ed. Paris: French Association of Standardization; 1988

Studies. 2016;**73**:286-293

[2] Harhar H, Gharby S, Kartah B, El Monfalouti H, Guillaume D, Charrouf Z. Influence of argan kernel roasting-time on virgin argan oil composition and oxidative stability. Plant Food for Human Nutrition.

**73**

Section 3

Quality of Raw Materials

in Food Processing

Section 3
