*3.3.1 Composition of saponifiable and unsaponifiable fractions*

Chemically, oils and fats are mixtures composed mainly of triacylglycerols formed from a glycerol molecule esterified with three fatty acids. The crude oil usually contains monoacylglycerols, diacylglycerols, free fatty acids, waxes, phospholipids, sphingolipids, glycolipids, terpenes, sterols, tocopherols, and carotenoids as minority compounds [20]. The unsaponifiable matter consists of solubilized minority compounds in oils and fats that are extractable with organic solvents after saponification [60]. Nunes (2013) found 0.76% unsaponifiable matter in crude macauba pulp oil, while Breves (2018) found 2% unsaponifiable matter in crude macauba kernel oil [61, 62].

### *3.3.2 Fatty acid composition*

The macauba kernel oil is characterized by the predominance of oleic acid and lauric acid, and presents a translucent aspect, while the pulp oil has an orange color and is characterized by a high concentration of oleic acid and carotenoids, which may


#### **Table 2.**

*Fatty acid profile of macauba oils (pulp and kernel). Source: Coimbra and Jorge [14].*

provide high oxidative stability [63, 64]. **Table 2** presents the fatty acids profile of macauba pulp and kernel oils.

The low content of polyunsaturated fatty acids (linoleic—C18:2 and linolenic— C18:3) can also affect the oxidative stability of the pulp oil, corresponding to 15%. On the other hand, the kernel oil presents a peculiar fatty acid composition, because although it has 32.58% of lauric acid (C12:0), which is a lower level when compared to conventional lauric oils, such as coconut, palm kernel, and babassu, it has more than 35% of oleic acid, an unusual content among all vegetable oils of this class.

#### *3.3.3 Triacylglycerol composition*

The macauba pulp oil presents a smaller range of carbon groups, comprising 48–54 carbon groups. Fourteen distinct triacylglycerols were identified, corresponding to 17.07% OOO, 6.36% OOL, 28.53% POO, and 10.53% PLP [65]. Lieb et al. analyzed macauba pulp oil from Costa Rica and found 20.8% OOO, 10.4% OOL, 13.0% POO, and 1.5% PLP (P: palmitic; Po: palmitoleic, S: stearic; O: oleic; L: linoleic) [48]. This divergence of values is due to the different origins of the fruits and the extraction method used to obtain the crude oil.

#### *3.3.4 Tocopherols, carotenoids, and phenolic compounds*

Natural antioxidants found in vegetable oils, such as tocopherols and tocotrienols, have four isomers, designated as alpha (α), beta (β), gamma (γ), and delta (δ),

*Macauba (*Acrocomia aculeata*): Biology, Oil Processing, and Technological Potential DOI: http://dx.doi.org/10.5772/intechopen.105540*


#### **Table 3.**

*Tocopherols, carotenoids, and phenolics concentrations in macauba oils.*

depending on the number and position of methyl groups in a chromanol ring. Tocopherols are characterized by a saturated side chain, while tocotrienols present an unsaturated side chain, and they also have a vitamin E activity in humans. They are also recognized for slowing down the lipid oxidation process. The antioxidant activity of tocopherols in food increases progressively for the δ, β, γ, and α isomers. On the other hand, tocotrienols are less effective than their corresponding isomers [66].

Carotenoids constitute a diverse group of lipophilic compounds that provide yellowish to red color to oils and are also known as bioactive compounds with proven health benefits [66].

Coimbra and Jorge characterized the macauba kernel and pulp oils for the concentration of phenolic compounds, carotenoids, and tocopherols, and the findings are shown in **Table 3** [14].

#### *3.3.5 Oxidative stability*

Factors that affect or catalyze the lipid oxidation include the presence of unsaturated or double bonds in fatty acids, light, temperature, prooxidants and antioxidants, enzymes, and storage conditions. In addition, the oxidative stability reflects the quality of the raw material from harvest to processing, leading to undesirable flavors that reduce the quality and shelf life of oils [67].

Breves [62] studied the oxidative stability of macauba kernel and pulp oils according to ISO 6886, and reported 41.35 and 16.36 min at 110°C, respectively. It is worth noting that the stability of the pulp oil is relatively lower than that of the kernel oil, due to the higher number of unsaturated fatty acids [62].

#### *3.3.6 Oil refining*

Refining can be defined as a series of distinct steps aimed at reducing undesirable substances from crude oils that can affect the stability and sensory properties. It removes colloidal substances, phosphatides, free fatty acids, natural pigments, such as chlorophyll and carotenoids, inorganic substances, such as calcium salts, metals, and phosphates, among others, and volatile compounds, such as peroxides, hydrocarbons, alcohols, aldehydes, ketones, and low-molecular weight esters, and water [20].

The selection of the adequate refining process is directly related to the free fatty acid content (%) of the crude oil and can be done through a chemical or physical process.

**Figure 2.**

The chemical process is not indicated for high acidity oils since significant losses of neutral lipids may occur due to saponification or soapstock dragging. For acidic oils, physical refining is indicated and should be performed under high temperature and low pressure, volatilizing and removing free fatty acids with reduced loss of neutral lipids [68].

In addition, phospholipid contents are the second factor to be considered before selecting the refining process. Chemical refining is indicated for high phosphorus levels, while the physical refining process is more usual for oils with low phosphorus levels [60]. For macauba pulp oil, both types of refining can be used due to its nonstandardization as acidic oil (**Figure 2**).

Degumming is the first step for obtaining the refined oil, either for physical or chemical processes, in which phospholipids are converted into oil-insoluble hydratable gums that are easily separated by sedimentation, filtration, or centrifugation through the addition of water and/or acid solution. This step is important for the removal of phospholipids, which can precipitate during the storage, affecting the quality of the oil and the subsequent refining steps. Additionally, it is possible to obtain lecithin, which is a by-product of high commercial value due to its emulsifying effect [20, 60].

Neutralization is carried out during the chemical refining and consists of neutralizing and thus reducing the free fatty acids content by adding an alkaline solution. Diluted caustic soda is usually used in concentrations between 10 and 24° Bé (degrees Baumé). The concentration of caustic soda and its excess is dependent on the free fatty acids (FFA) content of the degummed oil to be neutralized, avoiding saponification of the oil [69].

The next step is known as clarification or bleaching. Its main objective is to remove pigments to obtain clear oils (an important factor for commercialization), in addition to removing other constituents, such as oxidation products, metal traces, phospholipids, and soaps, resulting from the chemical refining. According to Kaynak et al. [70], these impurities, when present in the oil, can contaminate the hydrogenation and interesterification catalysts, darken the oil, and decrease oxidative stability [20, 70].

The efficiency of the process is determined by adding clarifying clays, either natural or activated, via adsorption. Part of the pigments is adsorbed onto the clarifying clay through surface attraction forces, known as "Van de Waals forces." Other components are chemically bound to the surface of the clarifying clays by covalent or ionic bonds. Part of the impurities present in the oil is removed by trapping their molecules in the pores of the clay. Some minor components, such as oxidation compounds and pigments, are chemically altered during clarification due to the catalytic activity of some clays [69].

*Macauba (*Acrocomia aculeata*): Biology, Oil Processing, and Technological Potential DOI: http://dx.doi.org/10.5772/intechopen.105540*

Deodorization is the last step of chemical refining, with the elimination of volatile compounds such as remaining free fatty acids and peroxides that give the oil an unpleasant aroma and flavor. The deodorization is done through steam distillation, removing volatile substances through a high vacuum [69].

In physical refining, the last step consists of distillation, with oil deacidification through the removal of free fatty acids, volatiles, and oxidation products [69]. The process is carried out through the association of high temperature and low absolute pressure, favoring the acceleration of distillation and preserving the oil from atmospheric oxidation [61].

According to the CODEX Alimentarius CXS 210-199 for vegetable oils, refined oils should have a maximum acidity of 0.6 mg KOH/g oil and up to 10 mEq O2 kg−1 [71].

#### *3.3.7 Refining the by-product: deodorizing the distillate*

It is estimated that a great amount of industrialized vegetable products, corresponding to 15–20%, are not used. The volume of these residues can reach even higher levels depending on the raw material, the processing applied, equipment used, and process yield, among others. All these factors induce the generation of by-products for food, fertilization, and feed production. Researchers have attempted to use by-products from the processing of vegetable raw materials, including vegetable oils, and once besides adding value to the by-products, it reduces the disposal in nature, helps in the environmental preservation, and promotes the integral use of the vegetable sources [72].

In addition to the refined oil, the distillate is obtained during the refining process, known as vegetable oil deodorization distillate (VODD). It is a by-product of the industrial processing of vegetable oils and is considered a low-cost source rich in health-giving components, such as tocopherols and phytosterols, in addition to FFA with numerous industrial applications. The distillates from physical refining have FFA contents above 70% and lower levels of unsaponifiable materials [73].

The research team of the Laboratory of Oils and Fats of the Faculty of Food Engineering—UNICAMP, Campinas, Brazil, studied the distillates from the deodorization of macauba kernel and pulp oils from physical refining. The kernel distillate presented 14.49 mg/100 g of γ-tocopherol and 0.79 mg/100 g of γ-tocotrienol. In turn, the pulp distillate presented 80.27 mg/100 g of γ tocopherol, 25.84 mg/100 g of β tocopherol, and 5.64 mg/100 g of γ tocotrienol (unpublished data).

According to Tay et al. [74], the free fatty acid content of palm oil deodorized distillate ranged from 72.7% to 92.6%. The author studied the co-product of palm oil refining and found VODD content of 86.4% [74]. These valuable components can be used in food, pharmaceutical, and cosmetic formulations [73].

#### **3.4 Emerging technologies**

The great potential of macauba has led to the development of several processing technologies for kernel and pulp oils. Favaro et al. studied the aqueous extraction of oil from fresh macauba pulp using the commercial enzyme Cellic® CTec3 and reported that the aqueous extraction was effective for obtaining high-quality oil [75]. Rosa et al. evaluated the effectiveness of ethyl acetate as a solvent in macauba kernel oil extraction by ultrasound-assisted extraction. Increasing the amount of solvent, the higher temperatures, and longer extraction times led to a higher amount of oil extracted [76]. Trentini et al. extracted macauba pulp oil by low-pressure solvent extraction and reported higher yields by using isopropanol as a solvent [77]. Prates-Valério et al. [78] studied

different mechanical extraction conditions for obtaining pulp oil, aiming to produce an extremely productive raw material. The fruit pressed at 34°C resulted in higher oil quality when compared to other temperatures studied [78]. Favaro et al. evaluated the extraction efficiency and quality of pulp oil extracted using aqueous media from wet fruits and reported an acidity of 0.45% oleic acid [79]. Malaquias et al. estimated macauba yield by regression models using the variables bunch volume, length, and length/diameter ratio [80]. Colombo et al. studied the physicochemical characteristics of macauba and reported the high potential of this fruit [5].

#### **3.5 Lipid modification processes**

To meet market demands and provide varied and uniform raw materials, lipid modification processes allow flexibility and contribute to reducing the gap between production site, demand, and availability. The most commonly used modification processes include hydrogenation, fractionation, and interesterification, using analytical or computational methods to ensure process efficiency [20, 69].

## *3.5.1 Fractionation*

The fractionation process consists of a thermomechanical separation in which the lipid material is separated into two or more fractions with different physical and chemical properties, due to the difference in the melting point of triacylglycerols. A fraction called olein is obtained, composed of a greater amount of triacylglycerols with a lower melting point, which is present in liquid form, and a semisolid fraction called stearin, composed of triacylglycerols with a higher melting point [81, 82]. Magalhães et al. [83] performed the fractionation of macauba kernel oil and evaluated the olein and stearin fractions for thermal behavior and consistency. The authors concluded that fractionation allowed obtaining fractions with different degrees of oxidative stability and different physical properties for various applications [83].

#### *3.5.2 Hydrogenation*

The presence of double bonds interferes with the chemical and physical properties of oils and fats. The hydrogenation reaction is a physicochemical process that leads to the saturation of the double bonds of unsaturated fatty acids through the addition of hydrogen atoms [20, 69].

Hydrogenation takes place in hermetic tanks, in which hydrogen gas is mixed with the raw material in the presence of a nickel catalyst, at high temperatures and high pressure. During partial hydrogenation, part of the double bonds of fatty acid is saturated, while some *cis* double bonds undergo isomerization and are converted to *trans*. A fully hydrogenated oil or fat is obtained after the hydrogenation of all double bonds. Fully hydrogenated vegetable oils are currently the technological alternative to produce fats with specific functional properties through both chemical and enzymatic interesterification reactions [84].

Various harmful effects have been associated with the consumption of *trans* fat in foods since these isomers are structurally similar to saturated fats, competing with essential fatty acids in complex metabolic pathways. In addition, they are cited as lipids that act as risk factors for coronary artery disease. Several countries have established changes in legislation, including Brazil through the Resolution (RDC) 332/2019, which sets limits on industrial fats for the food industry, with a ban on

the use of partially hydrogenated fat until 2023 [85, 86]. The Pan American Health Organization launched an action plan to eliminate industrial *trans* fatty acids between 2020 and 2025, and in 2018 the World Health Organization warned the world about the need to remove these fats from the global food supply [87].
