Do you often hear people say that soy milk and acidic foods cannot be eaten together? Have people around you become wary of acidic foods after drinking soy milk? There are some so-called health and wellness articles on the Internet that often give guidance and advice to some people. But some of them are eye-catching, exaggerated, and eloquent, making the listeners tremble and cautious.
About the fact that soy milk cannot be eaten with acidic foods such as yogurt, it is said that they are mutually resistant. I sorted it out and divided the rumors in the food industry into three types:
The first type is surreal sci-fi. For example, many years ago, it was said that some fast food restaurants used a lot of chicken legs and chicken wings. They said that they injected hormones into chickens, so that one chicken had eight chicken legs and eight chicken wings.
The second type of rumor is through the phenomenon of fantasy. For example, some people on the Internet claim that the reason why instant food can be kept for so long is because it contains a lot of additives and people eat too much. It will then become a mummy.
The third type is the most difficult to identify. I call it the unreasonable type based on a certain theoretical basis, that is, the soy milk and yogurt that I want to say today are mutually exclusive. This rumor There are three reasons why soymilk and yogurt are mutually resistant: 1. The protein in soymilk is denatured and precipitated when encountering acidic substances, making it difficult to digest and absorb; 2. Soymilk protein is hydrolyzed when encountering yogurt, and the protein loses its nutritional function; 3. Soy milk is rich in calcium, which forms calcium salts with yogurt, which is not conducive to the absorption of calcium.
In recent years, on food safety issues, especially on issues related to food interdependence, food researchers have been working on adopting more scientific and well-founded theoretical methods to help people eat well. Habits and ways to make recommendations so that everyone can understand more comprehensively and feel more at ease on food safety. And is soy milk really compatible with acidic foods such as yogurt, so that they cannot be eaten together? We analyze this problem from a scientific point of view.
The human stomach is a strong acid environment. The stomach can secrete gastric acid, which can maintain the stomach in a strong acid environment with a pH value of about 1.8. Only in this way can we ensure that the food that everyone eats is digested and decomposed by gastric acid and the first sterilization. That is to say, an acidic environment is the basis for promoting food digestion. Even if there is no acidic food such as yogurt, after we consume soy milk, the protein in soy milk will also denature in our stomach.
After the protein in soy milk is denatured, the secondary and tertiary structure of the protein will be destroyed, so that it will become more loose, and even under strong acid, the disulfide bond on its structure will be broken and some peptides will be broken. The bond is hydrolyzed, which is more favorable for it to be hydrolyzed by protease in the stomach, so that its nutritional value can be better digested, absorbed and utilized.
In addition, after milk is fermented, lactose is converted into lactic acid and some other organic acids (such as citric acid, acetic acid, etc.) The concentration of free calcium ions is helpful to promote the absorption of mineral ions such as Ca; secondly, when dietary protein is sufficient, some amino acids such as lysine, arginine, tryptophan, etc. can be combined with calcium to form soluble complexes substance, which is good for calcium absorption. Especially some acidic amino acids, which can promote the concentration of free calcium ions. In addition, yogurt contains a small amount of lactose. When lactose is absorbed in the distal intestinal segment, it can form a soluble, low-molecular-weight complex with calcium, which is beneficial for calcium to pass through the intestinal wall.
As one of the excellent sources of plant protein, soybean is rich in protein content and various essential amino acids required by the human body, so it is favored by more and more food researchers, and is committed to developing Its more potential edible methods and nutritional value. Among them, soy yogurt is also one of the hot spots.
Research shows that about 30% of lactose in soy yogurt is converted into various organic acids (such as formic acid, citric acid, acetic acid, etc.), which can increase the unique flavor of yogurt and inhibit the reproduction of harmful microorganisms. Promote gastric secretion and gastric and intestinal peristalsis, and promote the body’s absorption of calcium, phosphorus and iron. And soy yogurt has good value in both nutrition and health care.
Written by Zhang Na (Professor, School of Food Engineering, Harbin University of Commerce)
[Editor in charge: Shen Tian]