digestion, flatulence, and abdominal discomfort in humans (Steggerda et al. 1966).
Also, it has been observed that these oligosaccharides are poorly metabolized by
ruminants and, thus, decrease its nutritive value (Coon et al. 1988). Nevertheless,
efforts have been made to reduce these negative effects by fermentation and germination (Neus et al. 2005).
The cell walls of the soybeans contain insoluble carbohydrates, viz., cellulose
(20%), hemicellulose (50%), pectin (30%), and some amount of starch (12%) (Warle
et al. 2015). Polysaccharides, oligosaccharides, lignin, and associated plant substances are termed dietary fiber and range between 9% and 16% in whole soybeans
(Esteves et al. 2010). Insoluble fraction (74–78%) is mainly composed of arabinose,
galactose, glucose, xylose, and uronic acids, and soluble fiber (22–26%) comprises
of arabinose, galactose, and uronic acids (Redondo-Cuenca et al. 2007). Although
they do not contribute nutritionally, they are now considered as an integral part of the
diet as they confer many health-protective effects, viz., reducing the risk of coronary
heart disease (Liu et al. 1999), stroke (Steffen et al. 2003), hypertension (Whelton
et al. 2005), diabetes (Montonen et al. 2003), obesity (Lairon et al. 2005), and certain
gastrointestinal disorders (Petruzziello et al. 2006).
1.3.2 Proteins
Protein content of soybean ranges from 33% to 45% (Machado et al. 2008). Soy
protein has garnered a lot of attention lately owing to it being at par with animal
proteins both in quantitative and qualitative terms and being the only vegetable food
containing all eight essential amino acids (Dudek 2013; Hark and Morrison 2000).
Methionine and cysteine are the only limiting factors in soybean; nevertheless, the
Protein Digestibility Corrected Amino Acid Score (PDCAAS) for whole soybeans is
0.92 which indicates that soy protein is excellent for human nutrition in terms of both
the amino acid pattern and protein digestibility. Thus, suggesting that soy food
consumption is the best way to increase protein consumption in vegetarian population (Burssens et al. 2011). In terms of protein characterization, just like other
legumes, the bulk of soybean proteins are the globulins. The four major fractions
are β-conglycinin (principal component), glycinin (principal protein), trypsin inhibitors, and enzymes and hemagglutinins (Burssens et al. 2011). Among these, glycinin
and α-, β-, and γ-conglycinin constitute the major legume storage proteins (Wolf
1970).
1.3.3 Lipids
The total fat content of soybean ranges from 16% to 22%. Among all the other
legumes, it contains highest amount of fat and contributes nearly 47% to its energy
1 Soybean (Glycine max)
5
Also, it has been observed that these oligosaccharides are poorly metabolized by
ruminants and, thus, decrease its nutritive value (Coon et al. 1988). Nevertheless,
efforts have been made to reduce these negative effects by fermentation and germination (Neus et al. 2005).
The cell walls of the soybeans contain insoluble carbohydrates, viz., cellulose
(20%), hemicellulose (50%), pectin (30%), and some amount of starch (12%) (Warle
et al. 2015). Polysaccharides, oligosaccharides, lignin, and associated plant substances are termed dietary fiber and range between 9% and 16% in whole soybeans
(Esteves et al. 2010). Insoluble fraction (74–78%) is mainly composed of arabinose,
galactose, glucose, xylose, and uronic acids, and soluble fiber (22–26%) comprises
of arabinose, galactose, and uronic acids (Redondo-Cuenca et al. 2007). Although
they do not contribute nutritionally, they are now considered as an integral part of the
diet as they confer many health-protective effects, viz., reducing the risk of coronary
heart disease (Liu et al. 1999), stroke (Steffen et al. 2003), hypertension (Whelton
et al. 2005), diabetes (Montonen et al. 2003), obesity (Lairon et al. 2005), and certain
gastrointestinal disorders (Petruzziello et al. 2006).
1.3.2 Proteins
Protein content of soybean ranges from 33% to 45% (Machado et al. 2008). Soy
protein has garnered a lot of attention lately owing to it being at par with animal
proteins both in quantitative and qualitative terms and being the only vegetable food
containing all eight essential amino acids (Dudek 2013; Hark and Morrison 2000).
Methionine and cysteine are the only limiting factors in soybean; nevertheless, the
Protein Digestibility Corrected Amino Acid Score (PDCAAS) for whole soybeans is
0.92 which indicates that soy protein is excellent for human nutrition in terms of both
the amino acid pattern and protein digestibility. Thus, suggesting that soy food
consumption is the best way to increase protein consumption in vegetarian population (Burssens et al. 2011). In terms of protein characterization, just like other
legumes, the bulk of soybean proteins are the globulins. The four major fractions
are β-conglycinin (principal component), glycinin (principal protein), trypsin inhibitors, and enzymes and hemagglutinins (Burssens et al. 2011). Among these, glycinin
and α-, β-, and γ-conglycinin constitute the major legume storage proteins (Wolf
1970).
1.3.3 Lipids
The total fat content of soybean ranges from 16% to 22%. Among all the other
legumes, it contains highest amount of fat and contributes nearly 47% to its energy
1 Soybean (Glycine max)
5