Why do the dietary guidelines of various countries recommend the consumption of soybeans?
1.The nutritional value of soybeans
(1) Nutrient types and characteristics of soybeans
The protein content of soybeans is as high as 35%-40%. Soy protein is composed of globulin, albumin, gluten and gliadin, of which globulin is the most content.
Soy protein has a high content of lysine, a better amino acid pattern, and high nutritional value. It is a high-quality protein. Mixed consumption of soybeans and cereals can better play the complementary role of protein.
Soybean fat content is about 15%-20%. Soybeans and black beans are higher, which can be used to squeeze oil. Soybean oil is mostly unsaturated fatty acids, accounting for about 85% of the total fat, of which linoleic acid is 52% to 57%. In addition, soybean oil also contains 1.64% phospholipids. Soybean contains 25% to 30% carbohydrates, half of which is available arabinose, galactan and sucrose, and contains less starch. Soybeans are rich in calcium, iron, thiamine and riboflavin, as well as vitamin E.
(2) Special ingredients in soybeans
- Soy Isoflavones:Soy isoflavones can inhibit the bone resorption of osteoclasts by binding to estrogen receptors in bone tissues, thereby preventing osteoporosis.
- Soy Saponin:It has antibacterial, antiviral and immune function enhancement effects.
- Soy Sterol:The intake of soy sterol can hinder the absorption of cholesterol and inhibit the rise of serum cholesterol, so it has the effect of lowering blood lipids, and plays a role in preventing and treating cardiovascular diseases such as hypertension and coronary heart disease.
- Soy Lecithin:Soy lecithin is a light yellow to brown viscous or powdery substance obtained in the refining process of soybean oil. It is insoluble in water but easily soluble in many organic solvents. Soy lecithin has a certain preventive effect on nutrition-related chronic diseases such as hyperlipidemia and coronary heart disease.
- Soy oligosaccharides:Soy oligosaccharides can be used by intestinal probiotics, and have the functions of maintaining intestinal ecological balance, improving immunity, lowering blood pressure, lowering blood lipids, etc., and are called “prebiotics”.
Seeing so many nutrients and functions of soybeans, I can’t help but sigh. Soybeans are so good. Can you eat more and unlimited amounts?
Of course not!
2.Why can’t you eat more soybeans?
In addition to many nutrients, soybeans also contain some anti-nutrient factors, such as phytic acid, protease inhibitors, beany flavor, phytohemagglutinin and so on.
Phytic acid: It has always been a strong chelating agent for metal ions. It can chelate with calcium, zinc, iron and other minerals in the intestinal tract and affect its absorption. Soaking soybeans in a solution with a pH of 4.5-5.5 can dissolve 35%-75% of phytic acid, but has little effect on protein quality.
Protease inhibitor: It will reduce the nutritional value of soybeans, but it can be destroyed by heating under regular pressure steam for 30 minutes.
Phytohemagglutinin: It can cause dizziness, headache, nausea, vomiting, etc. after eating in large amounts for several hours. It can be destroyed by heating.
Soy products are also a good choice. Soy products include non-fermented soy products and fermented soy products: tofu, dried tofu, soy milk, vermicelli, noodles, fermented soy products, and soy protein products.