(1) Improve nutritional value and replace lean meat. Soy protein is a full-price protein, which can be directly absorbed by the human body and is the main indispensable nutrient component of the human body. The protein content of 500g soy protein is equivalent to the protein content of 2~2.5kg pure lean pork, and the addition of meat products can also play a complementary role of animal protein and plant protein. There are many benefits of the complementarity of the two proteins. The albumin in meat and the soy protein in soy protein are all complete proteins with high physiological value. The two proteins complement each other and can improve the physiological value of the protein. In the processing of meat products, if the two proteins are matched properly and reasonably, the edible value can be greatly improved. In addition, soy protein isolate can also replace lean meat processed emulsified meat products.
(2) Improve the structure of meat products and the quality of meat products. The compactness of the structure of meat products and the homogeneity of the cut surface are mainly related to the viscosity between the tissues during processing. In the process of separation and extraction of soy protein, the viscosity of the protein increases due to acid-base treatment. As a result, the soy protein is added to meat products, and its tissue structure is greatly improved, which can make the internal structure of the product fine, good combination, elasticity, good slicing, cut and smooth and delicate, taste good, and improve the product’s quality. Tenderness increases the fresh aroma of the product, and can also maintain the original flavor of the product.
(3) Emulsification of fat The so-called emulsification is the process of dispersing two kinds of immiscible liquids (such as water and fat) in the form of droplets or balls in the other liquid evenly. Among them, the dispersed phase is called the dispersed phase, and the liquid containing the dispersed phase is called the continuous phase. Generally, the diameter of the dispersed phase droplets is between 0.1 and 50 μm. To maintain stable emulsification, an emulsifier must be present, because when fat and water are in contact, there is a greater surface tension between the two phases, and the emulsifier molecule has both a hydrophilic part and a hydrophobic part (that is, a hydrophilic part). The oil part), the hydrophilic part can be combined with water, and the lipophilic part can be combined with oil, so it can reduce the surface tension between the two phases and increase the stability of the emulsion. In the product raw materials, the dispersed phase is solid or liquid fat globules, and the continuous phase is an aqueous solution in which salt and protein are dissolved (or suspended).
In the processing of meat products, the soy protein isolate filled in the raw material of the product acts as an emulsifier in this system to promote the formation of oil-water emulsion and create a protective layer for the product. If the process is proper and the emulsification is good, the fat content in the product can reach 40%-50%, and 500g of soybean protein can emulsify about 2.5 kg of fat.
(4) Improve water retention. Because of the many polar groups in the long chain of soy protein structure, it can absorb water, and can retain water in the product to extend the shelf life. By comparison, among soy protein products, isolate soy protein has the highest water absorption, 3.5 to 4.0 times the dry weight, followed by concentrated soy protein, and tissue soy protein has better water absorption than soy flour. The water absorption of soy protein and the water retention of soy protein gel are related to pH. When the pH is 4.5, it absorbs water and retains the least water, and then as the pH is greater than or less than 4.5, the water absorption and water retention increase. This function is conducive to maintaining the gravy and helps the meat products maintain a good taste and flavor for the coming year for a long time.
(5) Strengthen the gel structure of meat products. The soy protein isolate molecules filled in the raw materials of the products combine with the free fat molecules among them to form a stable emulsification system. During the thermal processing of the product, the protein on the surface of the fat globules is denatured, and an elastic self-supporting gel is obtained, which tightly wraps the fat globules to form a uniform and elastic product tissue. If the heating temperature is 125°C, the gel is destroyed and the stable emulsification system is also destroyed, causing the product to produce oil.
At the same time, the gelatinity of soy protein can “solidify” the protein sol matrix into a stable structure with a certain mechanical strength, increase the chew feeling of food, and make elastic gel products.
(6) Increase product yield, reduce costs, and increase economic benefits. The addition of soybean protein in meat processing can not only improve product quality, but also increase product yield. For every 500g of soybean protein added, 2.5 kg or more of finished products can be added. As the production rate increases, the cost of the product will decrease, and the economic benefits will obviously increase. However, it should be noted that in a formula, soy protein is not added as much as possible, but it must be designed based on the specific circumstances of each formula, and a reasonable formula can achieve good results.