Enzymatic preparation of rice protein peptides and their applications

my country is a major rice producer, with an annual rice output of more than 180 million tons, accounting for about 42% of the world's total output. In addition to supplying people's daily diet, rice is also used in industrial production, such as the sugar industry, citric acid industry, monosodium glutamate production industry, feed industry, etc. Every 10 tons of starch sugar produced can produce 1 ton of rice residue. If the rice protein can be fully utilized, various high value-added products can be prepared. The protein content in rice is only about 8%. If rice is directly used as a raw material to extract protein, the cost is high and the efficiency is low. The industrial production of rice produces a large amount of scraps (rice protein powder), which can be used as a raw material for processing soy sauce and protein drinks, or degraded into polypeptides by proteases as raw materials for food additives, condiments, etc.

The enzymatic extraction of rice bran protein is to use proteases (papain, pancreatin, alkaline protease) to degrade and modify rice bran protein, so that it becomes a soluble peptide and is separated. The reaction conditions of the enzymatic extraction are relatively mild, and the protein is hydrolyzed into short peptide chains, which can improve the digestibility of the protein. Rice peptides mainly contain peptide mixtures and a small amount of free amino acids, water, sugars and inorganic salts, and are low in sensitivity and easy to digest and absorb. The quality of rice peptides determines its nutritional and functional properties. Peptide content is one of the key indicators for evaluating the quality of rice protein peptides, because the biological activity of rice protein peptides is mainly reflected by peptides. The higher the peptide content, the higher the purity of rice protein peptides; and the molecular weight directly determines the efficiency of rice protein peptides being absorbed and utilized by the human body, and determines the nutritional value of rice protein peptides. Studies have shown that the smaller the molecular weight of the peptide segment, the easier it is to be absorbed by the human body, and the higher its biological activity may be.

The rice protein peptides obtained by enzymatic treatment have good solubility, hygroscopicity, moisture retention, emulsification ability and emulsification stability, strong antioxidant properties, and fast absorption in the body and high utilization rate; they can be widely used in plant protein products, fish protein products and candies and pastries, which can not only improve the taste, but also improve the quality and shelf life. With the development of bioengineering technology and people's increasing demand for food functionality, peptides are increasingly used in food. Its addition can change the quality and flavor of food, and also increase its functionality, such as peptide drinks, peptide children's lunch, peptide elderly meal, peptide sports food, calcium absorption promoting food, etc.