Beans, wheat (flour), rice and other plants all contain a lot of plant proteins (for example, the seeds of soybeans contain as much as 40% protein), and the protein contained in various meats, dairy products and eggs are all animal proteins.
Generally speaking, plant protein is richer and more widely available than animal protein, and people's daily intake is also relatively large. In the process of processing, the cost and technology are relatively convenient and cheap. However, plant protein is the protein of plants, and the species and relative quantity of protein are different from the needs of our human body.
For example, there is a lack of immunoglobulin in plant protein, while lysine is relatively lacking in grain. The absorption of plant protein in human body is relatively more difficult than that of animal protein. This is because plant protein is wrapped in fiber membrane and difficult to digest. The animal protein comes from the object itself, and the species and structure of protein are closer to the structure and quantity of human tissue protein.
Protein of human body consists of 20 kinds of amino acids, of which 8 kinds of amino acids cannot be synthesized by human body and must be provided by food, which is called "essential amino acids". Animal protein usually contains these eight essential amino acids, especially in egg products and dairy products, so its nutritional value is higher than that of plant protein.
However, compared with plant protein, animal protein is beneficial to people of all ages, and it is an indispensable substance in the growth, development and health of teenagers. Supplementing protein to middle-aged people can enhance the memory of mental workers and enhance the endurance of manual workers; Supplementing the elderly with high-quality protein can delay aging and prevent various senile diseases.