SOYBEAN – NUTRITIONAL VALUE AND PROTEIN QUALITY

Soybean is often known as the vegetarian chicken because of the quality of protein content it offers, also soyachaap - a soybean product has similar texture to chicken.

Nowadays, soy foods have become quite popular specifically among vegans as a pure plant-based protein. Also, there are various types of soy-based products commonly consumed such as tofu, soya flour, soya milk, curd, soya nuggets, soybean oil, and fermented products like miso, tempeh.

What's so amazing about its nutritional profile?

Soybean is a legume, still, it differs nutritionally from other legumes because it’s much higher in fat, protein and low on carbohydrates.

Best Plant Protein - Quantity and Quality

Protein determining factor

The protein digestibility corrected amino acid scores (PDCAAS) for soy protein ranges from 0.9 to 1.0 depending upon the type of soya product. Recently, as per FAO, DIAAS (Digestible Indispensable Amino Acid Score) determines the digestibility of individual amino acids rather than the faecal digestibility of protein overall. The value of 0.75 which is the minimum value the FAO recommended and DIAAS of soya protein is 0.9.

Carbohydrates

The low carbohydrate content is composed of oligosaccharides, because they are poorly digested by intestinal enzymes, and travel to the colon, unable to stimulate the growth of bacteria such as bifidobacteria, that are considered to be advantageous to the host.

Fats

The fat content of soybeans is comprised of approximately

• 10% - 15% saturated,
• 19% - 41% monounsaturated
• 46% - 62% polyunsaturated fatty acids (PUFA)
• The ratio of omega 6: omega 3 is 7:1

Vitamins and Minerals

The potassium content is high mainly in potassium, calcium, iron and potassium.

Relevance of Isoflavones 

Isoflavones are biologically active compounds and hold significant importance when it comes to health. Soybean is high in isoflavones of various types, more specifically glycosides. In fermented soy products, like miso, tempeh and natto, there is a presence of considerable amounts of the isoflavones. The three isoflavones genistein, daidzein and their respective glycosides account for approximately 50%, 40% and 10%, respectively, of the total isoflavone content of soybeans.

Each gram of soy protein in soybeans and traditional soy foods gives approximately 3.5 mg of isoflavones. For instance, 100 g of tofu or 250 mL soy milk, typically provides about 25 mg isoflavones.

Daily amount of Soya Isoflavones - suggested to prevent a range of diseases

Therefore, soybean is a super legume with a wide nutritional profile and should be part of the diet.

REFERENCES

• Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature. Nutrients 2016, 8, 754; doi:10.3390/nu8120754
• Bolla, Soybean Consumption And Health Benefits.IJSTR©2015 .www.ijstr.org