Swati Shukla, SGM Prasad, John David, Souvik Tewari
Soybean contributes to 28% of the world’s edible oil, and is second in production of edible oils to palm oil. The soybean is a valuable legume because it does provide all of the essential amino acids for humans; however it is relatively low in the sulfur containing amino acids, cysteine and methionine. It is one of the few legumes that can be consumed as a complete protein. The soybean is comprised of approximately 37-42% protein. The two main proteins of soybean are 11S glycinin, and 7S β-conglycinin, both globular in structure. Glycinins composed of acid/base polypeptide units and contains a higher percentage of sulfur-containing amino acids. The carbohydrate composition of the soybean consists primarily of fiber. The primary non-fiber carbohydrates in soy are the oligosaccharides, raffinose, stachyose and verbiscose. Raffinose is a trisaccharide of galactose, glucose and fructose, bound by 1 to 6 and 1 to 2 glycosidic linkages respectively and stachyose is tetrasaccharide of 2 galactoses, glucose, and fructose bound by 1 to 6, 1 to 6, and 1 to 2 glycosidic linkages respectively. Neither is digested in the small intestines as humans lack the enzyme α galactosidase. Passed into the colon they serve as an energy substrate for colonic bacteria, producing hydrogen and methane, and hence flatulence.Soy research has many exciting advances as breeding and genetic modifications are allowing for higher protein beans and desirable fatty acids profiles for food use and for health. Soybean products are useful not only for the vegetarian, but also for other aspect of diet therapy. As a component of soy, isoflavones potentially have a wide range of positive effects on human health. Their complexity of structure and intestinal metabolism creates difficulties in the interpretation and comparison of experiments, but clearly there are many positive human health effects of isoflavones derived from soy.