Release of 6 protein to peptide and its influencing factors

After the protein enters the digestive tract of animals, it is hydrolyzed into OP and FAA under the action of many enzymes (see Table 3), and OP is the main component of feed protein digestion products. For example, in casein and soybean protein small intestine soluble chyme, peptides account for 76% of the total AA content (Meisel et al., 1987), and the chain length is almost between 2 and 6 aa residues (Grimble, 1986);

When casein and rapeseed meal were hydrolyzed by pepsin trypsin in vitro, the release of peptides accounted for 2 / 3 of the total AA. Current studies have shown that the ability of dietary protein releasing peptide and AA is related to at least the following factors.

Quality of protein in diet

The release of SP and FAA and the ratio between them are related to the quality of protein. The amount of SP released by casein in Chicken Intestines was higher than that of soybean cake (sklan et al., 1980); Asche et al. (1989) and raghunath et al. (1987) by comparing the chyme of animal intestines, it was found that the content of soluble peptide (macromolecular peptide, OP and SP) formed by animal protein and soybean cake in intestines was high, while the release of plant protein (such as wheat protein and corn protein) with poor AA balance was mainly FAA.

Savoie et al. (1987) compared the hydrolysates of 19 kinds of animal and plant (legume and cereal) proteins under the action of pepsin trypsin. It was found that the ratio of peptides released by animal protein to FAA was higher than that of legume protein, while cereal protein was the lowest.

The results of in vivo and in vitro digestion tests showed that although the types and composition patterns of AA released from various proteins were different, the essential AA contained in them was more easily released in the form of peptide or FAA (raghunath et al., 1987).

The amount of peptide released by feed protein is closely related to its AA composition: high-quality (high EAA content and balance) protein is easy to hydrolyze to produce op with low molecular weight and large quantity, while low-quality (lack and imbalance of EAA) protein produces peptide fragments with small quantity but large molecular weight (Meister, 1987).

Le Guowei et al. (1996) analyzed the pepsin pancreatin hydrolysates of several protein feeds, and found that the order of OP release was casein, fish meal, silkworm chrysalis, soybean meal, soybean cake, rapeseed cake and corn protein meal. Regression analysis showed that the release of oligopeptide was highly correlated with effective lysine (alys);

Another experiment also observed this phenomenon (Liu XuanZhen et al., 1996). Many experiments show that lysine digestibility of feed protein is highly related to nitrogen digestibility, which may be related to this phenomenon.

Protein AA sequence
Grimble et al. (1987) and Rees et al. (1988) reported that the length of peptide chains formed by proteins in the gut and the proportion of FAA depend on the sequence of AA in proteins. Casein digested by pepsin and trypsin produced higher content of macromolecular peptide than rice protein and wheat protein (matoba et al., 1982), while short chain peptide was mainly produced from high-quality protein (Grimble et al., 1989).

Le Guowei et al. (1996) showed that the higher proline, glutamic acid, phenylalanine and leucine were, the longer the op peptide chain was, while the higher arginine, lysine, aspartic acid and glycine were, the shorter the op peptide chain was.

Because Lys pro, Arg pro, Tyr pro, Phe pro and Trp Pro can't be hydrolyzed by pepsin, trypsin and chymotrypsin, and Pro is a nonpolar AA, which forms a rigid side chain through side chain rotation and connection with the main chain, and is not easily broken by hydrolase (Yan Longfei, 1988), the protein rich in these peptide bonds is over peptide formation Cheng will be restricted to some extent.

In addition, when the content of alanine and glutamic acid is high, it is not easy to break from the chain; the affinity of peptide containing hydrophobic phenylalanine to peptide carrier is high, and it is easy to be absorbed in the form of peptide.

Processing and storage conditions

Restani et al. (1992) found that the amount of SP released from steamed meat was less than that from FAA, while that from freeze-dried meat and fresh meat was more than that from FAA. Storage time also affects the release of peptides from protein raw materials. For example, Le Guowei et al. (1996) showed that the release of peptides from soybean meal with low effective lysine content and long-term storage after heating was only 63% of that from fresh soybean meal with high effective lysine content.

This is consistent with the research results of reducing the nutritional value of soybean meal by Maillard reaction found by Chung et al. (1986) and Swaisgood et al. (1991). Generally speaking, the research of processing technology and storage factors on protein peptide release is relatively lacking. Further analysis and Research on the relationship between them may help to understand the mechanism of processing, storage and other links affecting protein and AA nutritional value.

Shengnuo bio PRODUCT

Best sales manager contact

About Shengnuo

Chengdu Shengnuo Biotechnology Co., Ltd. has "Chengdu polypeptide drug engineering technology research center" in Chengdu, mainly engaged in polypeptide, polypeptide drug and beauty peptide research. Our zero defect has passed the FDA certification, and now it has become the first-class professional peptide drug and product development, technology transfer, technical service and peptide drug industry in the scale production and export of China's parks.