How to use enzyme technology to modify soy protein?
According to market needs, through the selection of different proteases, the adjustment of process conditions and the degree of hydrolysis, a variety of products with different functional characteristics can be developed and produced.
(1)Injectable protein isolate:
The product is used in the salted solution for injection of whole meat products, which can reduce the cooking loss of meat products and improve the quality of individual rows and cut surfaces of meat products. Since the product is usually added in a relatively small amount, below 3%, it is not necessary to strictly control the bitterness.
Such products are required to have a lower viscosity, and at the same time, the increase in foaming properties and the decrease in gel properties must be controlled within a certain range.
The viscosity is mainly determined by the molecular mass of the protein. The greater the molecular mass, the greater the viscosity. 80% of soybean protein has a molecular mass of more than 100,000 and has a relatively high viscosity. If it is directly applied to the injection of salted liquid for meat products, it will block the needle and cause difficulties in application. The limited enzymatic hydrolysis treatment of the separated protein can reduce its molecular mass distribution and reduce its viscosity.
Soy protein has thermal gel properties. Under certain pH conditions, the noggin is heated to depolymerize the molecules in the soy protein to form a linear macromolecular structure, and the hydrophobic groups are exposed; after cooling, the hydrophobic groups interact with each other. Function to form a network structure. The thermal gel performance of the protein isolate continues to decrease as the degree of hydrolysis increases.
The protein isolate maintains a certain degree of gelation, which can improve the elasticity and slice quality of the final meat product, and reduce its cooking loss. During production, lecithin can also be sprayed on its surface to improve its rehydration performance.
(2)Protein isolated for dairy products:
The protein content of ordinary dairy products is relatively low, and adding protein isolate to it has a good market prospect. At the same time, from the nutrition course, soy protein contains all kinds of essential amino acids needed by the human body and is a complete protein. In 1999, the U.S. FDA officially recognized the health function of soy protein and recognized its cholesterol-lowering effect as a good health raw material.
Using protease to hydrolyze the protein isolate, on the one hand, can make its solubility, viscosity and other properties meet the requirements of dairy products and solid beverages. For example, the addition of protein isolate in dairy products requires low viscosity, no peculiar smell, high solubility, and insoluble solids below a certain index; on the other hand, protein isolate by enzymatic hydrolysis has higher nutritional value. In addition to increased digestibility, it also has the functions of anti-oxidation and scavenging free radicals in the body.
(3)Other functional protein isolate products:
The wide application of protein isolate in food mainly lies in its good functional properties. During the enzymatic hydrolysis process, the functional properties of the protein isolate, such as solubility, viscosity, foaming, emulsifying, gelling, water-holding, and oil-holding properties will change.
According to market demand, carry out limited enzymatic hydrolysis of protein isolates, choose different enzyme types, adopt different plum hydrolysis conditions, and develop other products with different functions, such as acid-soluble protein isolates, high foaming protein isolates, and high emulsification. Separate protein and so on.
Acid-soluble protein isolate is a new functional protein product, which refers to a protein hydrolysate that can still be dissolved at the isoelectric point of the isolated protein.
This kind of protein can be reused in acidic beverages, and it has broad market space for future development. The production of ISSPH requires a higher degree of hydrolysis than other functional products. On the other hand, application in the beverage industry requires higher control of bitterness.