Constituting proteins in various tissues of human bodyamino acidThere is a certain proportion between, in order to meetprotein synthesisIn addition to sufficient amount of essential amino acids provided by dietary protein, there should be an appropriate proportion among various essential amino acids, calledEssential amino acidpattern.
The ideal protein system is completely based on the maintenance and production needs of animals to provide an appropriate amount of various essential amino acids.Although the absolute requirements of different poultry for a single amino acid vary greatly, the proportion of various amino acid requirements relative to a certain amino acid (lysine) has a certain regularity at a certain stage. The research on the ideal amino acid model (IAAP) is based on the following assumptions: for poultry, the IAAP is relatively constant, and is affected by variety, genderAge and other factors have little influence;With the growth of poultry, only a variety of absolute requirements are changed, while the mutual proportion remains basically unchanged.This assumption is basically true.Yin Qingqiang et al. conducted an experimental study on Roman laying hens at the age of 23 weeks, which showed that the composition and pattern of living tissues of the hens had almost no change before and after the experiment, which was the biggest advantage of ideal proteins.The ideal amino acid model is different from the amino acid requirement, and it is not affected by environmental conditions and feed concentration.The ideal protein amino acid pattern is based on the dietLysineIs the benchmark.The main reasons for taking lysine as the benchmark are as follows:
The analysis and determination of lysine are relatively easy and accurate, especially when compared withSulfur-containing amino acidCompared with tryptophan;
Lysine has simple physiological function and is mainly used for the synthesis of body proteins;
Lysine is the most studied amino acid, and it is also an amino acid with more in-depth research;
It is more economical to add lysine to the diet of livestock and poultry[1]。
Basic Introduction
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The closer the amino acid pattern of food protein is to that of human protein, the more it can be fully utilized by the body, and the higher its nutritional value is.When any essential amino acid in food is deficient or excessive, it can cause imbalance of amino acid in the body, make other amino acids unavailable, and affect protein synthesis.Therefore, food diversification is advocated in the diet, and multiple foods are mixed to make essential amino acids supplement each other, so that their patterns are closer to the needs of the human body, so as to improve the nutritional value of protein. This phenomenon is called "protein complementarity".Generally speaking, fish, milk, eggs and other animal proteinsAmino acid patternIt is close to human, so its nutritional value is also high. It is called complete protein. The amino acid of plant protein is far away from human, its nutritional value is low, and cereal protein is lackingLysine、Tryptophan, affecting its nutritional value, which we callRestricted amino acid（CAA）。When soybeans and cereals are used together, they have a good complementary effect, which is also a good way to improve the nutritional value of protein. Therefore, people also regard soybeans as high-quality protein, and this complementary effect should be taken at the same time, or not more than 5 hours.
significance
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Amino acid patternThe significance lies in promoting food diversification in diet, mixing various foodsessential amino acid Complement each other to make its mode closer to the needs of the human body, so as to improve the nutritional value of protein.The calculation method is to calculate the corresponding ratio of other amino acids with the tryptophan of the lowest content as 1.
Human protein amino acid pattern
Human protein and amino acid mode It is very important for human body to maintain the basic protein and amino acid mode for body health. The best mode of human protein and amino acid and the composition of amino acid rich in high-quality protein food in daily life are listed.The adulteration analysis of milk protein based on amino acid mode was used to simulate the adulteration of commercially available qualified milk and milk powder with flour and starchTryptophan, threonine, valine and lysine, and establish a simple amino acid model to identify milk protein adulteration[1]。Effects of different amino acid patterns on milk quality.The amino acid content and composition ratio of milk protein are very close to the amount of amino acid required by human body, and it is a protein with high nutritional value.The milk fat rate and milk yield have always been the two important indicators of dairy cattle breeding in China, but the selection of milk protein has been ignored, so the concentration of milk protein has always been low.Scholars proved that the height ofSaturated fatty acidPromotedcholesterolAnd thenCardiovascular diseaseAt the same time, researchers have shown that milk proteins not only supply amino acids and proteins to humans and newborn animals, but also some milk proteins and peptides and other active substances digested by them have specific physiological functions.Therefore, consumers prefer dairy products with low fat and high protein.Milk protein is an important index to measure the quality of milk, and also the main source of human dietary protein. Its importance has been widely concerned.However, the weak stage of China's animal husbandry is still the dairy cattle industry, and the level of milk protein is generally low. Therefore, the primary task of nutrition research is to improve the protein content and quality of milk through nutrition regulation.More than 90% of milk proteins in milk are de novo synthesized in the mammary gland, and the other part is transported from proteins in the blood.To improve the utilization rate of amino acid in the diet, change the distribution of nutrients in the body, increase the proportion of amino acid intake during the synthesis of milk protein, increase the production of milk protein and reduce the discharge of fecal nitrogen, the level of protein in the diet and the type of amino acid intake can be adjusted.Hormones act on the amino acid transport system and the blood flow of the breast, thereby improving the intake and utilization of amino acids in the breast, improving the synthesis rate of milk protein, and increasing the production of milk protein[2]。
