Soybean contains 60% of dry weight of soybean oil (20%) and protein content (40%). The rest is 35% carbohydrate and about 5% ash. Soy protein is heat-stable storage protein. The principal soluble carbohydrates of mature soybeans are the trisaccharide raffinose (0.1-1.0%) and disaccharide sucrose (2.5-8.2%) with one molecule of galactose, tetrasaccharide stachyose (1.4 to 4.1%) with one sucrose and two molecules of galactose. While the oligosaccharides raffinose and stachyose make the soybean seed more viable to desiccation. Sometimes, they contribute to flatulence and abdominal discomfort in humans and other monogastric animals because they are not digestible sugars. Undigested oligosaccharides are broken down in the intestine by native microbes, producing gases such as carbon dioxide, hydrogen, and methane. Since soluble soy carbohydrates are found in the whey and its degradation takes place during fermentation. The insoluble carbohydrates in soybeans consist of the complex polysaccharides cellulose, hemicellulose, and pectin. The majority of soybean carbohydrates can be called to dietary fiber. Within soybean oil, the lipid portion of the seed (2.5%) consists of the phytosterols: stigmasterol (17-21%), sitosterol (53-56%) and campesterol (20-23%). Saponins are sterols (a class of natural surfactants) and commonly used in preparation do soaps and cosmetic preparation. Whole soybeans contain this naturally occurring surfactants of 0.17 to 6.16%. Soybean alos contains iso-flavones like genistein, daidzein, glycitein (good natural source of phyto-estrogen with weak estrogenic activity), O-methylated isoflavone as soy food products. For this reason, soybean is a good source of protein, amongst many other known pulses especially for vegetarians who have requirement of this protein rich diet supplement according to the US Food and Drug Administration. Soy protein products can also be good substitutes for animal products to offer complete protein profile. Soy protein products can replace animal-based foods especially beneficial to diabetic patients as well as for heart patients. For human consumption, soybeans must be cooked with water or streamed well before consumption to destroy the trypsin inhibitors (serine protease inhibitors). However, raw soybeans are toxic upon consumption.
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*Corresponding author:
Dr. Kirti Rani Sharma,
Assistant Professor (II),
Amity Institute of Biotechnology,
Amity University Uttar Pradesh, Noida
Sec-125, Gautam Buddha Nagar, Noida-201303 (UP), India.
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