Kenaf (*Hibiscus cannabinus* L.) Seed Extract as a New Plant-Based Milk Alternative and Its Potential Food Uses

*Roselina Karim, Nor Aini Mat Noh, Shafa'atu Giwa Ibrahim, Wan Zunairah Wan Ibadullah, Norhasnida Zawawi and Nazamid Saari*

## **Abstract**

Kenaf (*Hibiscus cannabinus* L.) seed is rich in protein, fat, fiber, and other essential nutrients. Kenaf seed comprises of high protein (22–31%) and oil (22–25%) contents which suggested its high potential food application. This chapter discusses the potential and early development of kenaf-based plant-milk and tofu. The step-by-step processes involved in preparation of kenaf-based milk and kenaf-based tofu at laboratory-scale are illustrated. Soaking conditions (temperature and time) of kenaf seed as pretreatment in preparation of kenaf seed milk were highlighted. Hydration of kenaf seed were found to be faster at elevated temperature, however higher soaking temperature and prolonged soaking time causes some losses of protein (%) and solid content (%) which are unfavorable for production of highly nutritious plant-based milk. Furthermore, in preparation of kenaf-based tofu, soaking temperature of seed also affected the properties of the tofu. As the soaking temperature was increased from 25–65°C, the yield, hardness, and chewiness of kenaf tofu decreased. It was recommended that soaking of kenaf seed at 25°C and the use of aluminum potassium salt at 1.00 g% as coagulant produces kenaf-based tofu with optimum quality.

**Keywords:** kenaf seed, soaking temperature, milky extract, hydration, physicochemical quality, chemical composition, kenaf-based tofu

## **1. Introduction**

Kenaf (*Hibiscus cannabinus* L*.*) is one of the most important fiber crops, belonging to the family of Malvaceae. Kenaf is cultivated in more than 20 countries where it is widely grown in China, India, and Thailand [1]. Kenaf is a useful multi-purpose crop with various industrial applications from paper to furniture and from biofuel to textile. Besides being a cordage crop it has substantial role in the construction and automotive industry. Kenaf plant has a significant economic value since all parts of the plant including the stem, leaves, flowers, and seeds can be used to the full advantage for mankind. In the recent

years, considerable attention and research has been carried out on the potential application of kenaf seeds in the food industry. Kenaf seed is reported as rich in fat, protein, dietary fibers, and a good source of raw material for production of edible oil, flour, protein concentrate, as well as potential ingredient for nutraceuticals and functional foods [2–4].

## **2. Chemical composition**

The proximate composition of different varieties of kenaf seed is presented in **Table 1**. The kenaf seed cultivars QP3, V36, and KB6 were cultivated in Malaysia while the seed cultivar C14 was cultivated in Korea, originated from Italy [2, 5, 6]. The seed varieties possess different chemical composition due to variation in agronomic conditions such as soil type, environmental variation, agriculture input (such as fertilizer application), planting season, maturity stage, harvesting period, and postharvest treatments such as drying and storage conditions [2]. In general, kenaf seed is high in protein and fat content which comprises of 21.9–30.5% and 22.1–24.8%, respectively. Kenaf seed was also reported to have a considerable amount of carbohydrate (18.7–24.4%) and fibers (10.6–18.7%).

The fatty acid composition of kenaf milk was not affected by processing. Both the kenaf seed and the milk contain high concentration of hexadecanoic acid (palmitic acid), 9-octadecenoic acid (oleic acid) and 9,12-octadecadienoic acid (linoleic acid) (**Table 2**). These saturated and unsaturated fatty acids had been reported as the major fatty acids in other kenaf seed cultivars [7–9]. The kenaf seed and its milk were not significantly different in their saturated, mono- and poly-unsaturated fatty acids composition. Based on the 9-octadecenoic and 9,12-octadecadienoic acid contents, the oil from the kenaf seed and kenaf milk are less prone to rancidity and might be used as edible healthier oils. Oleic acid is suggested to show a protective effect on Alzheimer's disease and other neurological disorders. A study on mouse model supplemented with oleic acid and restricted cholesterol intake had reduced the Alzheimer's disease-type neuropathology [10]. Linoleic acid plays an important role in reducing the total cholesterol level. It was found that the presence of high linoleic acid (33.6%) in kenaf seed extract exhibited an anti-hypercholesterolemic effect [11]. The presence of these beneficial bioactive compounds suggested the potential nutraceutical properties of the kenaf seed and kenaf seed milk.

The amino acid profile of kenaf seed has not been well studied. The non-essential amino acids composition of kenaf seed were significantly higher than the kenaf milk except for the proline content (**Table 3**). Also, kenaf seed was significantly higher


**65**

**Table 3.**

*Amino acid profiles of KB6 kenaf seed and kenaf seed milk.*

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative…*

**formula**

**Methyl tetradecanoate (15:0)** C15H30O2 0.03 ± 0.01b 0.05 ± 0.01a **Hexadecanoic acid (16:0)** C16H32O2 26.71 ± 0.22a 26.11 ± 0.57a **9-Hexadecenoic acid (16:1)** C16H30O2 0.40 ± 0.02a 0.28 ± 0.01b **Heptadecanoic acid (17:0)** C17H34O2 0.04 ± 0.00b 0.05 ± 0.00a **Octadecanoic acid (18:0)** C18H36O2 3.17 ± 0.47a 2.94 ± 0.05a **9-Octadecenoic acid (18:1)** C18H34O2 33.80 ± 2.39a 40.41 ± 1.22a **9,12-Octadecadienoic acid (18:2)** C18H32O2 30.59 ± 0.62a 28.62 ± 0.86a **10-Nonadecenoic acid (20:1)** C20H38O2 0.55 ± 0.04b 0.74 ± 0.01a

**Docosanoic acid (22:0)** C22H44O2 0.15 ± 0.01a 0.19 ± 0.01a **Tetracosanoic acid (24:0)** C24H48O2 0.10 ± 0.01a 0.13 ± 0.02a **Saturated** 30.51 ± 0.73a 29.93 ± 0.84a **Monounsaturated** 34.75 ± 2.45a 41.12 ± 1.24a **Polyunsaturated** 30.59 ± 0.62a 28.62 ± 0.86a

*The values within the same row with different superscripts letters are significantly different at* P *≤ 0.05.*

*Composition and amount (%) of saturated and unsaturated fatty acids of kenaf seed KB6 variety.*

**Amino acids Kenaf seed (mg/g) Kenaf seed milk (mg/g) Asp** 114.39 ± 4.29a 94.21 ± 0.01a **Ser** 87.97 ± 5.92a 35.14 ± 0.01b **Glu** 124.37 ± 2.87a 58.77 ± 0.01c **Arg** 178.72 ± 0.89a 70.79 ± 1.61b **Gly** 62.21 ± 2.25a 23.79 ± 0.01b **Ala** 46.61 ± 4.33a 14.70 ± 0.01b **Pro** 35.69 ± 2.75b 54.31 ± 0.01a **Tyr** 34.15 ± 0.46a 11.04 ± 0.00b Non-essential 684.11a 362.75b **His** 39.67 ± 2.35a 17.79 ± 0.01b **Thr** 54.65 ± 2.31a 19.14 ± 0.01b **Lys** 59.87 ± 1.47<sup>b</sup> 56.81 ± 0.02b **Val** 64.11 ± 2.14a 28.24 ± 0.01c **Met** 28.09 ± 0.79a 12.00 ± 0.00b **Ile** 54.07 ± 0.36b 95.50 ± 1.35a **Leu** 91.32 ± 0.62b 129.59 ± 0.04a **Phe** 71.01 ± 0.51b 128.34 ± 0.04a Essential 462.79a 487.41a *The values within the same row with different superscripts letters are significantly different at* P *≤ 0.05.*

**Kenaf seed area (%) Kenaf milk area (%)**

C21H42O2 0.31 ± 0.01a 0.46 ± 0.18a

*DOI: http://dx.doi.org/10.5772/intechopen.94067*

**Methyl 18-methylnonadecanoate** 

**(21:0)**

**Table 2.**

**Chemical name Molecular** 

#### **Table 1.**

*Proximate composition of several kenaf seed varieties [2, 5, 6].*


*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative… DOI: http://dx.doi.org/10.5772/intechopen.94067*

#### **Table 2.**

*Milk Substitutes - Selected Aspects*

ticals and functional foods [2–4].

drate (18.7–24.4%) and fibers (10.6–18.7%).

**2. Chemical composition**

years, considerable attention and research has been carried out on the potential application of kenaf seeds in the food industry. Kenaf seed is reported as rich in fat, protein, dietary fibers, and a good source of raw material for production of edible oil, flour, protein concentrate, as well as potential ingredient for nutraceu-

The proximate composition of different varieties of kenaf seed is presented in **Table 1**. The kenaf seed cultivars QP3, V36, and KB6 were cultivated in Malaysia while the seed cultivar C14 was cultivated in Korea, originated from Italy [2, 5, 6]. The seed varieties possess different chemical composition due to variation in agronomic conditions such as soil type, environmental variation, agriculture input (such as fertilizer application), planting season, maturity stage, harvesting period, and postharvest treatments such as drying and storage conditions [2]. In general, kenaf seed is high in protein and fat content which comprises of 21.9–30.5% and 22.1–24.8%, respectively. Kenaf seed was also reported to have a considerable amount of carbohy-

The fatty acid composition of kenaf milk was not affected by processing. Both the kenaf seed and the milk contain high concentration of hexadecanoic acid (palmitic acid), 9-octadecenoic acid (oleic acid) and 9,12-octadecadienoic acid (linoleic acid) (**Table 2**). These saturated and unsaturated fatty acids had been reported as the major fatty acids in other kenaf seed cultivars [7–9]. The kenaf seed and its milk were not significantly different in their saturated, mono- and poly-unsaturated fatty acids composition. Based on the 9-octadecenoic and 9,12-octadecadienoic acid contents, the oil from the kenaf seed and kenaf milk are less prone to rancidity and might be used as edible healthier oils. Oleic acid is suggested to show a protective effect on Alzheimer's disease and other neurological disorders. A study on mouse model supplemented with oleic acid and restricted cholesterol intake had reduced the Alzheimer's disease-type neuropathology [10]. Linoleic acid plays an important role in reducing the total cholesterol level. It was found that the presence of high linoleic acid (33.6%) in kenaf seed extract exhibited an anti-hypercholesterolemic effect [11]. The presence of these beneficial bioactive compounds suggested the potential nutraceutical properties of the kenaf seed and kenaf seed milk.

The amino acid profile of kenaf seed has not been well studied. The non-essential amino acids composition of kenaf seed were significantly higher than the kenaf milk except for the proline content (**Table 3**). Also, kenaf seed was significantly higher

**Composition (%) Kenaf QP3 Kenaf V36 Kenaf KB6 Kenaf C14 Moisture** 8.5 8.4 9.0 8.3 **Crude protein**<sup>A</sup> 30.5 29.8 21.9 27.5 **Crude fat** 24.8 22.6 24.7 22.1 **Crude fiber** 12.5 11.5 18.7 10.6 **Ash** 4.5 4.5 6.2 5.8 **Total carbohydrate**<sup>B</sup> 19.2 23.2 18.7 24.4

**64**

*A*

*B*

**Table 1.**

*By difference.*

*Crude protein = N (%) × 6.25.*

*Proximate composition of several kenaf seed varieties [2, 5, 6].*

*Composition and amount (%) of saturated and unsaturated fatty acids of kenaf seed KB6 variety.*


#### **Table 3.**

*Amino acid profiles of KB6 kenaf seed and kenaf seed milk.*

than the milk in terms of the essential amino acids such as histidine, threonine, valine and methionine. These indicated that the processes of extraction of the kenaf milk affected the amino acid content of the milk. However, the total essential amino acids of the seed and the milk were not significantly different.

## **3. Seed hydration**

Soaking is commonly used in processing of grains, to soften and hydrate the seed before proceeding to other stages such as cooking, extraction, fermentation, germination and malting [12]. In preparation of a plant-based milk alternative, an initial soaking of the plant seed is a prerequisite before extraction of the milk constituent by wet milling. Soaking of seeds reduced the hard-to-cook nature by softening the texture of the seeds which in turn facilitates subsequent processes and reduces the cooking time. Soaking is a batch process which can take an average

**Figure 1.** *Moisture content (%) (d.b.) of kenaf seed soaked at different time and temperature.*

#### **Figure 2.**

*Effect of soaking temperatures on the scanning electron microscopy images of kenaf seeds. Note: A = unsoaked kenaf seed, B = kenaf seed soaked at 25°C, C = kenaf seed soaked at 45°C, D = kenaf seed soaked at 65°C, mw = major entrance of water, ca = caruncle, cty = cotyledon, end = endosperm, sc = seed coat, ins = intracellular spaces (adapted from [5]).*

**67**

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative…*

of 12 to 24 h at room temperature (25 + 2°C) and uses a substantial quantity of water. However, numerous ways to accelerate the process have been proposed which include soaking at elevated temperatures, high-power ultrasound, and high hydro-

**4. Effect of soaking condition on nutritional quality of kenaf** 

minimizing the solid loss during soaking process.

were also reported by other researchers [18, 20, 21].

Although the use of high soaking temperature acts as a steeping factor for the soaking process, it generates a notable loss of solids from seeds such as protein (%) and solid content (%). Therefore, in preparation of kenaf seed milk, selection of suitable soaking conditions (temperature and time) need to be considered in

**Figures 3** and **4** show the effect of soaking temperature towards the subsequent protein content (%) and solid content (%) (expressed in °Brix) of the kenaf seed milky extract, respectively (unpublished data). From **Figure 3**, the protein content of kenaf seed milky extract were found to be increased with prolonged soaking time at lower soaking temperatures (28°C and 40°C) and decreased throughout the soaking period after the first hour of soaking at higher temperature (50°C, 60°C, 80°C). This result may be due to the release of some seed component including proteins into the soaking medium which is enhanced by the higher soaking temperature and time. Soaking at higher temperature causes the loose of seed coat structure and thus the seed storage proteins (7S and 11S proteins) that are protected by the seed coat were released into the soaking medium by the force of concentration difference [19]. Other than proteins, the leaching of the seed component may include carbohydrates [20]. The release of soluble solids from the seed were found to increase at higher soaking temperature due to the extended seed wall rupture. Based on **Figure 4**, the solid content of kenaf seed milky extract increased with longer soaking time of kenaf seed at lower temperatures (28°C and 40°C), and decreased at higher temperature (50°C, 60°C, 80°C) of soaking. The increased of solid loss upon higher temperature of soaking

Hydration at higher temperature is one of the most frequently used techniques in enhancing the hydration rate of plant seeds. **Figure 1** shows the water absorption rate of kenaf seed as a function of soaking temperature and time (unpublished data). It was observed that the highest water absorption rate of kenaf seed was recorded at the highest soaking temperature (80°C). Higher soaking temperature causes reduction in the soaking medium viscosity which improves the capillary flow and dilatation of the tissues and pores, hence increases the water absorption rate [14]. At the beginning of soaking, water absorption rate was high, and it gradually slowed down towards the end of soaking process. The former action was due to the predominant of capillarity flow of seed hydration mechanism while the latter was due to diffusion process [13]. The effectiveness of using higher temperature in increasing the absorption rate was also reported in other studies [15–18]. Further investigation on the effect of kenaf seed hydration towards its microstructure was studied using the scanning electron microscopy and is presented in **Figure 2**. It was observed that kenaf seed soaked at 25°C (**Figure 2B**) had a more visible intracellular spaces than the seed soaked at 45°C (**Figure 2C**), and 65°C (**Figure 2D**). The intracellular spaces inside the seeds soaked at 45°C and 65°C were filled with water and both the endosperm and cotyledon segment appeared expanded. Therefore, it is evident that hydration rate of seed soaked at higher temperature increased and causes further improvement in the capillarity flow and dilatation of the tissues and

*DOI: http://dx.doi.org/10.5772/intechopen.94067*

static pressure [13].

pores of kenaf seed.

**seed milky extract**

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative… DOI: http://dx.doi.org/10.5772/intechopen.94067*

of 12 to 24 h at room temperature (25 + 2°C) and uses a substantial quantity of water. However, numerous ways to accelerate the process have been proposed which include soaking at elevated temperatures, high-power ultrasound, and high hydrostatic pressure [13].

Hydration at higher temperature is one of the most frequently used techniques in enhancing the hydration rate of plant seeds. **Figure 1** shows the water absorption rate of kenaf seed as a function of soaking temperature and time (unpublished data). It was observed that the highest water absorption rate of kenaf seed was recorded at the highest soaking temperature (80°C). Higher soaking temperature causes reduction in the soaking medium viscosity which improves the capillary flow and dilatation of the tissues and pores, hence increases the water absorption rate [14]. At the beginning of soaking, water absorption rate was high, and it gradually slowed down towards the end of soaking process. The former action was due to the predominant of capillarity flow of seed hydration mechanism while the latter was due to diffusion process [13]. The effectiveness of using higher temperature in increasing the absorption rate was also reported in other studies [15–18]. Further investigation on the effect of kenaf seed hydration towards its microstructure was studied using the scanning electron microscopy and is presented in **Figure 2**. It was observed that kenaf seed soaked at 25°C (**Figure 2B**) had a more visible intracellular spaces than the seed soaked at 45°C (**Figure 2C**), and 65°C (**Figure 2D**). The intracellular spaces inside the seeds soaked at 45°C and 65°C were filled with water and both the endosperm and cotyledon segment appeared expanded. Therefore, it is evident that hydration rate of seed soaked at higher temperature increased and causes further improvement in the capillarity flow and dilatation of the tissues and pores of kenaf seed.

## **4. Effect of soaking condition on nutritional quality of kenaf seed milky extract**

Although the use of high soaking temperature acts as a steeping factor for the soaking process, it generates a notable loss of solids from seeds such as protein (%) and solid content (%). Therefore, in preparation of kenaf seed milk, selection of suitable soaking conditions (temperature and time) need to be considered in minimizing the solid loss during soaking process.

**Figures 3** and **4** show the effect of soaking temperature towards the subsequent protein content (%) and solid content (%) (expressed in °Brix) of the kenaf seed milky extract, respectively (unpublished data). From **Figure 3**, the protein content of kenaf seed milky extract were found to be increased with prolonged soaking time at lower soaking temperatures (28°C and 40°C) and decreased throughout the soaking period after the first hour of soaking at higher temperature (50°C, 60°C, 80°C). This result may be due to the release of some seed component including proteins into the soaking medium which is enhanced by the higher soaking temperature and time. Soaking at higher temperature causes the loose of seed coat structure and thus the seed storage proteins (7S and 11S proteins) that are protected by the seed coat were released into the soaking medium by the force of concentration difference [19]. Other than proteins, the leaching of the seed component may include carbohydrates [20]. The release of soluble solids from the seed were found to increase at higher soaking temperature due to the extended seed wall rupture. Based on **Figure 4**, the solid content of kenaf seed milky extract increased with longer soaking time of kenaf seed at lower temperatures (28°C and 40°C), and decreased at higher temperature (50°C, 60°C, 80°C) of soaking. The increased of solid loss upon higher temperature of soaking were also reported by other researchers [18, 20, 21].

*Milk Substitutes - Selected Aspects*

**3. Seed hydration**

than the milk in terms of the essential amino acids such as histidine, threonine, valine and methionine. These indicated that the processes of extraction of the kenaf milk affected the amino acid content of the milk. However, the total essential amino

Soaking is commonly used in processing of grains, to soften and hydrate the seed before proceeding to other stages such as cooking, extraction, fermentation, germination and malting [12]. In preparation of a plant-based milk alternative, an initial soaking of the plant seed is a prerequisite before extraction of the milk constituent by wet milling. Soaking of seeds reduced the hard-to-cook nature by softening the texture of the seeds which in turn facilitates subsequent processes and reduces the cooking time. Soaking is a batch process which can take an average

acids of the seed and the milk were not significantly different.

**66**

**Figure 2.**

*ins = intracellular spaces (adapted from [5]).*

**Figure 1.**

*Moisture content (%) (d.b.) of kenaf seed soaked at different time and temperature.*

*Effect of soaking temperatures on the scanning electron microscopy images of kenaf seeds. Note: A = unsoaked kenaf seed, B = kenaf seed soaked at 25°C, C = kenaf seed soaked at 45°C, D = kenaf seed soaked at 65°C, mw = major entrance of water, ca = caruncle, cty = cotyledon, end = endosperm, sc = seed coat,* 

**Figure 3.**

*Protein content (%) of kenaf seed milky extract obtained from different soaking condition (time and temperature) of kenaf seed.*

#### **Figure 4.**

*Solid content (°brix) of kenaf seed milky extract obtained using different soaking condition (time and temperature) of kenaf seed.*

## **5. Kenaf seed milk**

**Figure 5** shows the procedures for the preparation of kenaf seed milk. Kenaf seed milk appears to be similar in appearance and texture to soymilk with creamy

**69**

**Figure 5.**

**Table 4.**

*based milk alternatives.*

*Processes in preparation of kenaf seed milk.*

**Compositions Kenaf seed** 

**milk**

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative…*

white in color. The taste of the unflavored kenaf seed milk is described as thin with a hint of earthy flavor. **Table 4** shows the proximate composition of kenaf milk in comparison to several commercially available plant-based milk alternatives. Kenaf seed milk contains 1.93–2.48% of protein and 2.10–2.60% fat which is comparable

*The proximate composition of kenaf seed milk (seed variety V36) and several commercially available plant-*

**Soymilk [22, 23]**

Moisture (%) 91.04 88.12–91.00 72.00–93.40 91.60 Protein (%) 1.93–2.48 3.82–3.98 1.90–2.50 0.83–4.00 Fat content (%) 2.10–2.60 3.10–4.30 3.20–3.60 1.25–3.00 Carbohydrate (%) 1.82 4.64–4.92 4.30–4.70 2.50–20.00 Ash content (%) 3.11 0.84–0.81 0.09–3.04 0.47

**Almond milk [22, 23]**

**Hemp milk [24, 25]**

Tofu is a popular and important protein source in most countries such as Asian, Western and African countries [26, 27]. Over the years, soybean has been the most commonly used legume for tofu production. However, several researchers have

to almond milk in terms of the protein and fat contents, respectively.

**6. Processing of value-added kenaf based tofu derived** 

**from kenaf seed milk**

*DOI: http://dx.doi.org/10.5772/intechopen.94067*

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative… DOI: http://dx.doi.org/10.5772/intechopen.94067*

#### **Figure 5.** *Processes in preparation of kenaf seed milk.*


#### **Table 4.**

*Milk Substitutes - Selected Aspects*

**68**

**Figure 4.**

**Figure 3.**

*temperature) of kenaf seed.*

**5. Kenaf seed milk**

*temperature) of kenaf seed.*

**Figure 5** shows the procedures for the preparation of kenaf seed milk. Kenaf seed milk appears to be similar in appearance and texture to soymilk with creamy

*Solid content (°brix) of kenaf seed milky extract obtained using different soaking condition (time and* 

*Protein content (%) of kenaf seed milky extract obtained from different soaking condition (time and* 

*The proximate composition of kenaf seed milk (seed variety V36) and several commercially available plantbased milk alternatives.*

white in color. The taste of the unflavored kenaf seed milk is described as thin with a hint of earthy flavor. **Table 4** shows the proximate composition of kenaf milk in comparison to several commercially available plant-based milk alternatives. Kenaf seed milk contains 1.93–2.48% of protein and 2.10–2.60% fat which is comparable to almond milk in terms of the protein and fat contents, respectively.

## **6. Processing of value-added kenaf based tofu derived from kenaf seed milk**

Tofu is a popular and important protein source in most countries such as Asian, Western and African countries [26, 27]. Over the years, soybean has been the most commonly used legume for tofu production. However, several researchers have

produced tofu from other grains such as peanut [28], lupin seed [29], sesame [30], chickpea and mung bean [31]; in most cases the selection of these grains were based on their high protein content and good functional properties. Kenaf seed have been reported to contain 21.4 to 30.5% protein on dry basis [6, 32] and protein has been known as one of the factors that affect tofu quality [29, 33, 34]. The general processing of soybean tofu involves soaking of the seed, grinding with water, boiling of the slurry, followed by separation of the milk from the residue (kenaf seed okara), cooking of the milk to 95°C, coagulating the cooked milk and molding [35]. Recently, we have produced kenaf-based tofu from kenaf seed milk and the effect of processing variables such as soaking temperature of kenaf seed, coagulant types and concentrations were investigated [5]. The outcomes of our research indicated that the yield, hardness, and chewiness of the kenaf-based tofu decreased as the soaking temperature increased from 25–65°C. Besides, the interaction among the processing variables such as coagulant type\*coagulant concentration, coagulant type\*soaking temperature and coagulant concentrations\*soaking temperature affected the yield, hardness, and chewiness of the kenaf-based tofu (**Figure 6**). It was discovered that soaking of kenaf seed at 25°C and using aluminum potassium salt as coagulant at concentration of 1.00 g% were recommended as the processing variables for optimum kenaf-based tofu production.

The procedure for kenaf-based tofu preparation slightly differs from the processing for soybean tofu whereby the kenaf seed slurry is not heated prior to extraction. Additionally, 1:5 to 1:8 soybean-to-water ratios were often used in the extraction of soybean milk for tofu production. However, in the case of kenaf-based

#### **Figure 6.**

*Surface plots of interactions of coagulant types, coagulant concentrations, and soaking temperature of seed on yield, hardness, and chewiness of kenaf-based tofu. Note: a, b, c = surface plots of yield; d, e, f = surface plots of hardness; g, h, i = surface plots of chewiness (adapted from [5]).*

**71**

noodles and pasta [40].

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative…*

tofu it was discovered that the most suitable ratio of kenaf seed to water for the extraction of the milk during tofu production was 1:3, based on the lower total soluble solids content of kenaf milk (unpublished data). The procedure for the production of kenaf-based tofu is presented in **Figure 7**, the kenaf seed was soaked at 25°C for 10 h and the soaked seed was ground at low speed using 1:3 kenaf seed-to-water ratio for 2–3 min. The slurry obtained was then filtered using muslin cloth to separate the kenaf seed residue from the milk. The milk obtained (400 ml) from 100 g of kenaf seed was heated until the temperature of the milk reached 95°C and the temperature was hold at this temperature for 2–3 min. Then, the milk was allowed to cool to 80°C at room temperature (25 ± 2°C) and the specified coagulant was added to form the kenaf seed curd. The curd was then transferred to a wooden mold lined with muslin cloth and pressed with a load of 5 kg for 5 min to remove excess water. A solid curd-like product known as kenaf seed tofu is formed and is

Several other potential food applications of kenaf seed have been postulated

based on the functional characteristics of its protein concentrate [36]. The authors have proposed the use of kenaf seed as an ingredient in the production of vegetable-based protein substitute such as tempeh and texturized vegetable protein. Tempeh is a fermented vegetable meat substitute produced by inoculating pre-cooked legumes such as soybean, lentils and common bean with *Rhizopus oligosporus* [37, 38]. Similarly, pre-cooked kenaf seed can be fermented with *Rhizopus oligosporus* to produce kenaf-based tempeh based on its high protein content and emulsifying property (unpublished data). Additionally, kenaf seed protein concentrate has been reported to have high thermal stability [2]. Thus, protein concentrate from kenaf seed can be extruded into slices, crumbles, flakes and chunks to produce a meat-like chewy texture similar to texturized soy protein [39]. Also, kenaf seed has been used in the form of defatted meal or flour for the production of

*DOI: http://dx.doi.org/10.5772/intechopen.94067*

ready to be used or consumed.

**Figure 7.**

**7. Other potential uses of kenaf seed**

*Procedures for production of kenaf seed tofu (adapted from [5]).*

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative… DOI: http://dx.doi.org/10.5772/intechopen.94067*

**Figure 7.** *Procedures for production of kenaf seed tofu (adapted from [5]).*

tofu it was discovered that the most suitable ratio of kenaf seed to water for the extraction of the milk during tofu production was 1:3, based on the lower total soluble solids content of kenaf milk (unpublished data). The procedure for the production of kenaf-based tofu is presented in **Figure 7**, the kenaf seed was soaked at 25°C for 10 h and the soaked seed was ground at low speed using 1:3 kenaf seed-to-water ratio for 2–3 min. The slurry obtained was then filtered using muslin cloth to separate the kenaf seed residue from the milk. The milk obtained (400 ml) from 100 g of kenaf seed was heated until the temperature of the milk reached 95°C and the temperature was hold at this temperature for 2–3 min. Then, the milk was allowed to cool to 80°C at room temperature (25 ± 2°C) and the specified coagulant was added to form the kenaf seed curd. The curd was then transferred to a wooden mold lined with muslin cloth and pressed with a load of 5 kg for 5 min to remove excess water. A solid curd-like product known as kenaf seed tofu is formed and is ready to be used or consumed.

## **7. Other potential uses of kenaf seed**

Several other potential food applications of kenaf seed have been postulated based on the functional characteristics of its protein concentrate [36]. The authors have proposed the use of kenaf seed as an ingredient in the production of vegetable-based protein substitute such as tempeh and texturized vegetable protein. Tempeh is a fermented vegetable meat substitute produced by inoculating pre-cooked legumes such as soybean, lentils and common bean with *Rhizopus oligosporus* [37, 38]. Similarly, pre-cooked kenaf seed can be fermented with *Rhizopus oligosporus* to produce kenaf-based tempeh based on its high protein content and emulsifying property (unpublished data). Additionally, kenaf seed protein concentrate has been reported to have high thermal stability [2]. Thus, protein concentrate from kenaf seed can be extruded into slices, crumbles, flakes and chunks to produce a meat-like chewy texture similar to texturized soy protein [39]. Also, kenaf seed has been used in the form of defatted meal or flour for the production of noodles and pasta [40].

*Milk Substitutes - Selected Aspects*

variables for optimum kenaf-based tofu production.

produced tofu from other grains such as peanut [28], lupin seed [29], sesame [30], chickpea and mung bean [31]; in most cases the selection of these grains were based on their high protein content and good functional properties. Kenaf seed have been reported to contain 21.4 to 30.5% protein on dry basis [6, 32] and protein has been known as one of the factors that affect tofu quality [29, 33, 34]. The general processing of soybean tofu involves soaking of the seed, grinding with water, boiling of the slurry, followed by separation of the milk from the residue (kenaf seed okara), cooking of the milk to 95°C, coagulating the cooked milk and molding [35]. Recently, we have produced kenaf-based tofu from kenaf seed milk and the effect of processing variables such as soaking temperature of kenaf seed, coagulant types and concentrations were investigated [5]. The outcomes of our research indicated that the yield, hardness, and chewiness of the kenaf-based tofu decreased as the soaking temperature increased from 25–65°C. Besides, the interaction among the processing variables such as coagulant type\*coagulant concentration, coagulant type\*soaking temperature and coagulant concentrations\*soaking temperature affected the yield, hardness, and chewiness of the kenaf-based tofu (**Figure 6**). It was discovered that soaking of kenaf seed at 25°C and using aluminum potassium salt as coagulant at concentration of 1.00 g% were recommended as the processing

The procedure for kenaf-based tofu preparation slightly differs from the processing for soybean tofu whereby the kenaf seed slurry is not heated prior to extraction. Additionally, 1:5 to 1:8 soybean-to-water ratios were often used in the extraction of soybean milk for tofu production. However, in the case of kenaf-based

*Surface plots of interactions of coagulant types, coagulant concentrations, and soaking temperature of seed on yield, hardness, and chewiness of kenaf-based tofu. Note: a, b, c = surface plots of yield; d, e, f = surface plots of* 

*hardness; g, h, i = surface plots of chewiness (adapted from [5]).*

**70**

**Figure 6.**

## **8. Conclusion**

Kenaf seed is a highly nutritious plant seed that should be further exploited in innovation of non-conventional plant-based milk alternative and other food uses. In this chapter, the soaking conditions (temperature and time) of kenaf seed were studied. Higher soaking temperature and prolonged soaking time of kenaf seed were not recommended as they caused the loss of protein (%) and soluble solids (%) of the seed milky extract. Higher soaking temperature was also found to reduce the physical properties (yield, hardness, and chewiness) of kenaf-based tofu. It is recommended to use a lower temperature (25°C and 40°C) of soaking to preserve the nutritional value and quality of the subsequent products. Further and more thorough research ought to be done to produce a highly nutritious and highest quality of plant-based milk and tofu from kenaf seed that are comparable to the established soymilk and soy tofu, respectively.

## **Acknowledgements**

This research was supported and funded by the National Kenaf and Tobacco Board of Malaysia (Vote No.:6300910-UPM), Tertiary Education Trust Fund (TETFund) and Usmanu Danfodiyo University, Sokoto (UDUS).

## **Author details**

Roselina Karim1 \*, Nor Aini Mat Noh1 , Shafa'atu Giwa Ibrahim1,2, Wan Zunairah Wan Ibadullah3 , Norhasnida Zawawi3 and Nazamid Saari3

1 Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia

2 Department of Biochemistry, Faculty of Science, Usmanu Danfodiyo University, Sokoto, Nigeria

3 Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia

\*Address all correspondence to: rosaz@upm.edu.my

© 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.

**73**

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative…*

[7] Nyam KL, Tan CP, Lai OM, Long K, Man YBC. Physicochemical properties and bioactive compounds of selected seed oils. LWT - Food Sci Technol.

[9] Chew SC, Tan CP, Long K, Nyam KL. Effect of chemical refining on the quality of kenaf (Hibiscus cannabinus) seed oil. Industrial Crops and Products.

[10] Amtul Z, Westaway D, Cechetto DF, Rozmahel RF. Oleic acid ameliorates amyloidosis in cellular and mouse models of Alzheimer's disease. Brain Pathology. 2011;**21**(2):321-329

[11] Kai NS, Nee TA, Lai E, Ling C, Ping TC, Kamariah L, et al. Antihypercholesterolemic effect of kenaf (Hibiscus cannabinus L.) seed on high-fat diet Sprague Dawley rats. Asian Pac J Trop Med [Internet]. 2015;8(1):6- 13. Available from: http://dx.doi. org/10.1016/S1995-7645(14)60179-6

[12] Deshpande SS, Sathe SK,

Press, Inc.; 1989. p. 133-40.

Safety. 2018;**17**(2):352-370

[14] Oliveira AL, Colnaghi BG, Zucatti E, Gouvêa IR, Vieira RL, Esteves P, et al. Modelling the effect of

[13] Miano AC, Augusto PED. The hydration of grains: A critical review from description of phenomena to process improvements. Comprehensive Reviews in Food Science and Food

Salunkhe DK. Soaking. In: Salunkhe DK, Kadam SS, editors. CRC Handbook of World Food Legumes: Nutritional Chemistry, Processing Technology, and Utilization. Boca Raton, Florida: CRC

2009;**42**(8):1396-1403

2016;**89**:59-65

[8] Mohamed A, Bhardwaj H, Hamama A, Webber C. Chemical composition of kenaf (Hibiscus cannabinus L.) seed oil. Industrial Crops and Products. 1995;**4**(3):157-165

*DOI: http://dx.doi.org/10.5772/intechopen.94067*

[1] Cheng W-Y, Haque Akanda JM, Nyam K-L. Kenaf seed oil: A potential new source of edible oil. Trends in Food Science and Technology [Internet]. 2016 Jun 1 [cited 2020 Mar 13];52:57- 65. Available from: https://www. sciencedirect.com/science/article/pii/ S0924224415301242?via%3Dihub

[2] Mariod AA, Fathy SF, Ismail M. Preparation and characterisation of protein concentrates from defatted kenaf seed. Food Chemistry [Internet].

[3] Chan KW, Khong NMH, Iqbal S, Mansor SM, Ismail M. Defatted kenaf seed meal (DKSM): Prospective edible flour from agricultural waste with high antioxidant activity. LWT - Food Sci Technol [Internet]. 2013;53(1):308- 13. Available from: http://dx.doi. org/10.1016/j.lwt.2013.01.003

[4] Dhar P, Kar CS, Ojha D, Pandey SK, Mitra J. Chemistry, phytotechnology, pharmacology and nutraceutical functions of kenaf (Hibiscus

cannabinus L.) and roselle (Hibiscus sabdariffa L.) seed oil: An overview. Industrial Crops and Products [Internet]. 2015;77:323-32. Available from: http://dx.doi.org/10.1016/j.

[5] Ibrahim G, Mat Noh NA, Wan Ibadullah WZ, Saari N, Karim R. Water soaking temperature of kenaf (Hibiscus cannabinus L.) seed, coagulant types, and their concentrations affected the production of kenaf-based tofu. Journal of Food Processing & Preservation.

November 2019;**2020**:1-13

2018;**21**(3):229-239

[6] Kim D, Ryu J, Lee M, Kim JM, Ahn J, Kim J, et al. Nutritional properties of various tissues from new kenaf cultivars. J Crop Sci Biotech.

indcrop.2015.08.064

2010;123(3):747-52. Available from: http://dx.doi.org/10.1016/j.

foodchem.2010.05.045

**References**

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative… DOI: http://dx.doi.org/10.5772/intechopen.94067*

## **References**

*Milk Substitutes - Selected Aspects*

**8. Conclusion**

**72**

**Author details**

**Acknowledgements**

Roselina Karim1

Sokoto, Nigeria

Wan Zunairah Wan Ibadullah3

\*, Nor Aini Mat Noh1

established soymilk and soy tofu, respectively.

Universiti Putra Malaysia, Serdang, Selangor, Malaysia

Putra Malaysia, Serdang, Selangor, Malaysia

provided the original work is properly cited.

\*Address all correspondence to: rosaz@upm.edu.my

, Shafa'atu Giwa Ibrahim1,2,

and Nazamid Saari3

, Norhasnida Zawawi3

This research was supported and funded by the National Kenaf and Tobacco Board of Malaysia (Vote No.:6300910-UPM), Tertiary Education Trust Fund

(TETFund) and Usmanu Danfodiyo University, Sokoto (UDUS).

Kenaf seed is a highly nutritious plant seed that should be further exploited in innovation of non-conventional plant-based milk alternative and other food uses. In this chapter, the soaking conditions (temperature and time) of kenaf seed were studied. Higher soaking temperature and prolonged soaking time of kenaf seed were not recommended as they caused the loss of protein (%) and soluble solids (%) of the seed milky extract. Higher soaking temperature was also found to reduce the physical properties (yield, hardness, and chewiness) of kenaf-based tofu. It is recommended to use a lower temperature (25°C and 40°C) of soaking to preserve the nutritional value and quality of the subsequent products. Further and more thorough research ought to be done to produce a highly nutritious and highest quality of plant-based milk and tofu from kenaf seed that are comparable to the

2 Department of Biochemistry, Faculty of Science, Usmanu Danfodiyo University,

3 Department of Food Science, Faculty of Food Science and Technology, Universiti

© 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,

1 Department of Food Technology, Faculty of Food Science and Technology,

[1] Cheng W-Y, Haque Akanda JM, Nyam K-L. Kenaf seed oil: A potential new source of edible oil. Trends in Food Science and Technology [Internet]. 2016 Jun 1 [cited 2020 Mar 13];52:57- 65. Available from: https://www. sciencedirect.com/science/article/pii/ S0924224415301242?via%3Dihub

[2] Mariod AA, Fathy SF, Ismail M. Preparation and characterisation of protein concentrates from defatted kenaf seed. Food Chemistry [Internet]. 2010;123(3):747-52. Available from: http://dx.doi.org/10.1016/j. foodchem.2010.05.045

[3] Chan KW, Khong NMH, Iqbal S, Mansor SM, Ismail M. Defatted kenaf seed meal (DKSM): Prospective edible flour from agricultural waste with high antioxidant activity. LWT - Food Sci Technol [Internet]. 2013;53(1):308- 13. Available from: http://dx.doi. org/10.1016/j.lwt.2013.01.003

[4] Dhar P, Kar CS, Ojha D, Pandey SK, Mitra J. Chemistry, phytotechnology, pharmacology and nutraceutical functions of kenaf (Hibiscus cannabinus L.) and roselle (Hibiscus sabdariffa L.) seed oil: An overview. Industrial Crops and Products [Internet]. 2015;77:323-32. Available from: http://dx.doi.org/10.1016/j. indcrop.2015.08.064

[5] Ibrahim G, Mat Noh NA, Wan Ibadullah WZ, Saari N, Karim R. Water soaking temperature of kenaf (Hibiscus cannabinus L.) seed, coagulant types, and their concentrations affected the production of kenaf-based tofu. Journal of Food Processing & Preservation. November 2019;**2020**:1-13

[6] Kim D, Ryu J, Lee M, Kim JM, Ahn J, Kim J, et al. Nutritional properties of various tissues from new kenaf cultivars. J Crop Sci Biotech. 2018;**21**(3):229-239

[7] Nyam KL, Tan CP, Lai OM, Long K, Man YBC. Physicochemical properties and bioactive compounds of selected seed oils. LWT - Food Sci Technol. 2009;**42**(8):1396-1403

[8] Mohamed A, Bhardwaj H, Hamama A, Webber C. Chemical composition of kenaf (Hibiscus cannabinus L.) seed oil. Industrial Crops and Products. 1995;**4**(3):157-165

[9] Chew SC, Tan CP, Long K, Nyam KL. Effect of chemical refining on the quality of kenaf (Hibiscus cannabinus) seed oil. Industrial Crops and Products. 2016;**89**:59-65

[10] Amtul Z, Westaway D, Cechetto DF, Rozmahel RF. Oleic acid ameliorates amyloidosis in cellular and mouse models of Alzheimer's disease. Brain Pathology. 2011;**21**(2):321-329

[11] Kai NS, Nee TA, Lai E, Ling C, Ping TC, Kamariah L, et al. Antihypercholesterolemic effect of kenaf (Hibiscus cannabinus L.) seed on high-fat diet Sprague Dawley rats. Asian Pac J Trop Med [Internet]. 2015;8(1):6- 13. Available from: http://dx.doi. org/10.1016/S1995-7645(14)60179-6

[12] Deshpande SS, Sathe SK, Salunkhe DK. Soaking. In: Salunkhe DK, Kadam SS, editors. CRC Handbook of World Food Legumes: Nutritional Chemistry, Processing Technology, and Utilization. Boca Raton, Florida: CRC Press, Inc.; 1989. p. 133-40.

[13] Miano AC, Augusto PED. The hydration of grains: A critical review from description of phenomena to process improvements. Comprehensive Reviews in Food Science and Food Safety. 2018;**17**(2):352-370

[14] Oliveira AL, Colnaghi BG, Zucatti E, Gouvêa IR, Vieira RL, Esteves P, et al. Modelling the effect of temperature on the hydration kinetic of adzuki beans (Vigna angularis). Journal of Food Engineering [Internet]. 2013;118(4):417-20. Available from: http://dx.doi.org/10.1016/j. jfoodeng.2013.04.034

[15] Shafaei SM, Masoumi AA, Roshan H. Analysis of water absorption of bean and chickpea during soaking using Peleg model. Journal of the Saudi Society of Agricultural Sciences [Internet]. 2016;15(2):135-44. Available from: http://dx.doi.org/10.1016/j. jssas.2014.08.003

[16] Johnny S, Razavi SM, Khodaei D. Hydration kinetics and physical properties of split chickpea as affected by soaking temperature and time. Journal of Food Science and Technology. 2015;**52**(12):8377-8382

[17] Quicazán MC, Caicedo LA, Cuenca M. Applying Peleg's equation to modelling the kinetics of solid hydration and migration during soybean soaking. Ing e Investig. 2012;**32**(3):53-57

[18] Khazaei J, Mohammadi N. Effect of temperature on hydration kinetics of sesame seeds (Sesamum indicum L.). Journal of Food Engineering [Internet]. 2009;91(4):542-52. Available from: http://dx.doi.org/10.1016/j. jfoodeng.2008.10.010

[19] Li X, Liu X, Hua Y, Chen Y, Kong X, Zhang C. Effects of water absorption of soybean seed on the quality of soymilk and the release of flavor compounds. RSC Advances. 2019;**9**(6):2906-2918

[20] Pan Z, Tangratanavalee W. Characteristics of soybeans as affected by soaking conditions. LWT - Food Sci Technol. 2003;**36**(1):143-151

[21] Lima FS De, Kurozawa LE, Ida EI. The effects of soybean soaking on grain properties and isoflavones loss. LWT - Food Sci Technol [Internet].

2014;59(2):1274-82. Available from: http://dx.doi.org/10.1016/j. lwt.2014.04.032

[22] Kundu P, Dhankhar J, Sharma A. Development of non dairy milk alternative using soymilk and almond milk. Curr Res Nutr Food Sci. 2018;**06**(1):203-210

[23] Alozie YE, Udofia US. Nutritional and sensory properties of almond (Prunus amygdalu var. Dulcis) seed milk. World Journal of Dairy & Food Sciences. 2015;**10**(2):117-121

[24] Chich owska J, Kliber A, Biskupski M, Grygorowicz Z. Insulin, thyroid hormone levels and metabolic changes after treated rats with hemp milk. 2002; Available from: https://pdfs. semanticscholar.org/2625/168857ebe1cf4 bfb987532dcc278c2d92eb5.pdf

[25] USDA. United States Department of Agriculture food composition database [Internet]. [cited 2020 Sep 8]. Available from: https://ndb.nal.usda.gov/

[26] Zhu Q, Wu F, Saito M, Tatsumi E, Yin L. Effect of magnesium salt concentration in water-in-oil emulsions on the physical properties and microstructure of tofu. Food Chemistry. 2016;**201**:197-204

[27] Oboh G. Coagulants modulate the hypocholesterolemic effect of tofu (coagulated soymilk). African J Biotechnol. 2006;**5**(3):290-294

[28] Guo Y, Hu H, Wang Q, Liu H. A novel process for peanut tofu gel: Its texture, microstructure and protein behavioral changes affected by processing conditions. LWT - Food Sci Technol. 2018;**96**:140-146

[29] Jayasena V, Khu WS, Nasar-Abbas SM. The development and sensory acceptability of lupin-based

**75**

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative…*

in Food Science and Nutrition.

[38] Vital RJ, Bassinello PZ, Cruz QA, Carvalho RN, Paiva JCM, Colombo AO. Production, quality, and acceptance of tempeh and white bean tempeh burgers.

Extrusion process parameters, sensory

[40] Zawawi N, Gangadharan P, Ahma Zaini R, Samsudin MG, Karim R, Maznah I. Nutritional values and cooking quality of defatted kenaf seeds yellow (DKSY) noodles. International Food Research Journal. 2014;**21**(2):603-608

2015;**55**(9):1241-1245

Food. 2018;**7**(136):1-9

2002;**67**:1066-1072

[39] Lin S, Huff HE, Hsieh F.

characteristics, and structural properties of a high moisture soy protein meat analog. J Food Sci.

*DOI: http://dx.doi.org/10.5772/intechopen.94067*

[31] Mohamed S, Johan Z, Chickpea BJ. Mungbean, cowpea and peanuts as substitutes for soybean curds. International Journal of Food Science and Technology. 1989;**24**(4):385-394

Jimoh WA, Fawole WO, Orisasona O, Ojo-Daniel AH. Effect of cooking and roasting on nutritional and antinutritional factors in kenaf (Hibiscus cannabinus L.) seed meal. Food Sci Qual Manag. 2014;**24**:2224-6088

tofu. Journal of Food Quality.

[30] Sato E. Effects of different kind of sesame materials on the physical properties of gomatofu (sesame tofu). Food Hydrocolloids.

[32] Olawepo KD, Banjo OT,

[33] Mujoo R, Trinh DT, Ng PK. Characterization of storage proteins in different soybean varieties and their relationship to tofu yield and texture. Food Chemistry. 2003;**82**(2):265-273

[34] Evans DE, Tsukamoto C, Nielsen NC. A small scale method for the production of soymilk and silken tofu. Crop Science.

[35] Cao FH, Li XJ, Luo SZ, Mu DD, Zhong XY, Jiang ST, et al. Effects of organic acid coagulants on the physical properties of and chemical interactions in tofu. LWT - Food Sci Technol.

[36] Giwa Ibrahim S, Karim R, Saari N, Wan Abdullah WZ, Zawawi N, Ab Razak AF, et al. Kenaf (Hibiscus cannabinus L.) seed and its potential food applications: A review. Journal of Food Science. 2019;**84**:2015-2023

[37] Malav OP, Talukder S,

Gokulakrishnan P, Chand S. Meat analogue: A review. Critical Reviews

1997;**37**(5):1463-1471

2017;**85**:58-65

2010;**33**(1):85-97

2003;**17**(6):901-906

*Kenaf (*Hibiscus cannabinus *L.) Seed Extract as a New Plant-Based Milk Alternative… DOI: http://dx.doi.org/10.5772/intechopen.94067*

tofu. Journal of Food Quality. 2010;**33**(1):85-97

*Milk Substitutes - Selected Aspects*

2013;118(4):417-20. Available from: http://dx.doi.org/10.1016/j.

[15] Shafaei SM, Masoumi AA,

Roshan H. Analysis of water absorption of bean and chickpea during soaking using Peleg model. Journal of the Saudi Society of Agricultural Sciences [Internet]. 2016;15(2):135-44. Available from: http://dx.doi.org/10.1016/j.

[16] Johnny S, Razavi SM, Khodaei D. Hydration kinetics and physical properties of split chickpea as affected by soaking temperature and time. Journal of Food Science and Technology.

jfoodeng.2013.04.034

jssas.2014.08.003

2015;**52**(12):8377-8382

[17] Quicazán MC, Caicedo LA,

Ing e Investig. 2012;**32**(3):53-57

2009;91(4):542-52. Available from: http://dx.doi.org/10.1016/j.

[20] Pan Z, Tangratanavalee W.

Technol. 2003;**36**(1):143-151

Characteristics of soybeans as affected by soaking conditions. LWT - Food Sci

[21] Lima FS De, Kurozawa LE, Ida EI. The effects of soybean soaking on grain properties and isoflavones loss. LWT - Food Sci Technol [Internet].

jfoodeng.2008.10.010

Cuenca M. Applying Peleg's equation to modelling the kinetics of solid hydration and migration during soybean soaking.

[18] Khazaei J, Mohammadi N. Effect of temperature on hydration kinetics of sesame seeds (Sesamum indicum L.). Journal of Food Engineering [Internet].

[19] Li X, Liu X, Hua Y, Chen Y, Kong X, Zhang C. Effects of water absorption of soybean seed on the quality of soymilk and the release of flavor compounds. RSC Advances. 2019;**9**(6):2906-2918

temperature on the hydration kinetic of adzuki beans (Vigna angularis). Journal of Food Engineering [Internet]. 2014;59(2):1274-82. Available from: http://dx.doi.org/10.1016/j.

milk. Curr Res Nutr Food Sci.

Sciences. 2015;**10**(2):117-121

[24] Chich owska J, Kliber A,

bfb987532dcc278c2d92eb5.pdf

from: https://ndb.nal.usda.gov/

[26] Zhu Q, Wu F, Saito M,

[22] Kundu P, Dhankhar J, Sharma A. Development of non dairy milk alternative using soymilk and almond

[23] Alozie YE, Udofia US. Nutritional and sensory properties of almond (Prunus amygdalu var. Dulcis) seed milk. World Journal of Dairy & Food

Biskupski M, Grygorowicz Z. Insulin, thyroid hormone levels and metabolic changes after treated rats with hemp milk. 2002; Available from: https://pdfs. semanticscholar.org/2625/168857ebe1cf4

[25] USDA. United States Department of Agriculture food composition database [Internet]. [cited 2020 Sep 8]. Available

Tatsumi E, Yin L. Effect of magnesium salt concentration in water-in-oil emulsions on the physical properties and microstructure of tofu. Food Chemistry. 2016;**201**:197-204

[27] Oboh G. Coagulants modulate the hypocholesterolemic effect of tofu (coagulated soymilk). African J Biotechnol. 2006;**5**(3):290-294

[28] Guo Y, Hu H, Wang Q, Liu H. A novel process for peanut tofu gel: Its texture, microstructure and protein behavioral changes affected by

processing conditions. LWT - Food Sci

Technol. 2018;**96**:140-146

[29] Jayasena V, Khu WS, Nasar-Abbas SM. The development and sensory acceptability of lupin-based

lwt.2014.04.032

2018;**06**(1):203-210

**74**

[30] Sato E. Effects of different kind of sesame materials on the physical properties of gomatofu (sesame tofu). Food Hydrocolloids. 2003;**17**(6):901-906

[31] Mohamed S, Johan Z, Chickpea BJ. Mungbean, cowpea and peanuts as substitutes for soybean curds. International Journal of Food Science and Technology. 1989;**24**(4):385-394

[32] Olawepo KD, Banjo OT, Jimoh WA, Fawole WO, Orisasona O, Ojo-Daniel AH. Effect of cooking and roasting on nutritional and antinutritional factors in kenaf (Hibiscus cannabinus L.) seed meal. Food Sci Qual Manag. 2014;**24**:2224-6088

[33] Mujoo R, Trinh DT, Ng PK. Characterization of storage proteins in different soybean varieties and their relationship to tofu yield and texture. Food Chemistry. 2003;**82**(2):265-273

[34] Evans DE, Tsukamoto C, Nielsen NC. A small scale method for the production of soymilk and silken tofu. Crop Science. 1997;**37**(5):1463-1471

[35] Cao FH, Li XJ, Luo SZ, Mu DD, Zhong XY, Jiang ST, et al. Effects of organic acid coagulants on the physical properties of and chemical interactions in tofu. LWT - Food Sci Technol. 2017;**85**:58-65

[36] Giwa Ibrahim S, Karim R, Saari N, Wan Abdullah WZ, Zawawi N, Ab Razak AF, et al. Kenaf (Hibiscus cannabinus L.) seed and its potential food applications: A review. Journal of Food Science. 2019;**84**:2015-2023

[37] Malav OP, Talukder S, Gokulakrishnan P, Chand S. Meat analogue: A review. Critical Reviews in Food Science and Nutrition. 2015;**55**(9):1241-1245

[38] Vital RJ, Bassinello PZ, Cruz QA, Carvalho RN, Paiva JCM, Colombo AO. Production, quality, and acceptance of tempeh and white bean tempeh burgers. Food. 2018;**7**(136):1-9

[39] Lin S, Huff HE, Hsieh F. Extrusion process parameters, sensory characteristics, and structural properties of a high moisture soy protein meat analog. J Food Sci. 2002;**67**:1066-1072

[40] Zawawi N, Gangadharan P, Ahma Zaini R, Samsudin MG, Karim R, Maznah I. Nutritional values and cooking quality of defatted kenaf seeds yellow (DKSY) noodles. International Food Research Journal. 2014;**21**(2):603-608

**77**

**Chapter 5**

**Abstract**

bifidobacteria, probiotics

groats, flour in baking bread or cakes.

**1. Introduction**

Bifidobacteria

*Ewa Kowalska and Małgorzata Ziarno*

The Possibility of Obtaining

with Lactic Acid Bacteria and

Buckwheat Beverages Fermented

In this study, we aimed to examine the effect of four different industrial starter cultures containing lactic acid bacteria and bifidobacteria on the selected characteristics of beverages prepared from buckwheat and stored at 4°C for 28 days. We estimated the pH of the beverages during fermentation and storage under refrigerated conditions. We also determined the number of lactic acid bacteria and bifidobacteria and performed a chromatographic analysis of the carbohydrates. According to the results, the tested starter cultures effectively fermented the buckwheat beverage. The viable cell count of the starter microflora was sufficient to demonstrate the health-promoting properties of buckwheat. The pH of beverages was stable during the refrigerated storage. However, the carbohydrate content of the stored beverages

changed, which indicates a constant biochemical activity of the microflora.

**Keywords:** buckwheat, health, lactic acid bacteria, lactic acid fermentation,

In recent years, the eating habits of people have changed dramatically due to various reasons. One such reason is consumer awareness of the impact of food on human health. Products that have a natural composition, that are unprocessed, and are nongenetically modified are preferred the most by the consumers. Another important factor, which determines people's eating habits, is food allergies and intolerances, which eliminate the possibility of consumption of a particular food product. Food allergies and metabolic disorders have led to an increased demand for allergen-free food products that meet the daily requirements for protein and other nutrients. For example, in the case of gluten intolerance, it is impossible to eat food products containing gluten. For such individuals, an alternative food product is, among others, buckwheat, which, as a gluten-free pseudocereal, can be used as

Buckwheat has a rich composition and high nutritional value and can be an ideal base for products that are enriched with lactic acid bacteria (LAB), including probiotics. They are defined as a functional food because when they are administered in adequate amounts, they confer specific health benefits to the consumer. Consuming

## **Chapter 5**
