With the change of lifestyle in recent years, the number of conditioned meat products is quietly increasing, ranging from a variety of semi-finished fried chicken nuggets, seasoned meat steaks and barbecue products, to the main products of convenience stores such as skewers and bentos. Through retail terminals, conditioned meat products are increasingly infiltrating into the household consumption of Chinese people, and gradually becoming popular in consumption.

Classification of Soy Protein

1. Soy flour
Most soybean flour is “defatted and deodorized soybean”, which is cheap because of its low protein content. When used in meat products, it can keep twice its own weight in water, and soybean flour emulsion can keep the same weight of fatty substances without oil during thermal processing. Soy flour has poor functionality, has many shortcomings in taste and flavor, and is subject to many restrictions in the scope and amount of use.

2. Soy protein concentrate
The protein content of soybean protein concentrate is about 70%, most of which are used in meat products. The emulsified gel ratio of soybean protein concentrate is protein: water: fat = 1:4:3, which acts on meat products to improve the taste and structure, and increase the protein content of the product.

3. Soy protein isolate
Soybean protein isolate is a protein produced from low-temperature desolvated soybean meal. Among them, the protein content is more than 90%, there are nearly 20 kinds of amino acids, and it contains essential amino acids for human body. It is rich in nutrients and does not contain cholesterol, so it is widely used in prepared meat products.

4. Textured soybean protein
Textured soybean protein is a product made from defatted soybean powder, concentrated soybean protein or isolated soybean protein, etc., under mechanical and thermal effects such as stirring, extrusion, and puffing. Such proteins have a certain meat-like chew. Therefore, the application in conditioning meat has a special application, and can replace some lean meat raw materials.

Functional properties and effects of soybean protein

1. Water retention
The water retention of soybean protein plays an important role in the production of meat products, especially the ability to absorb, combine and bind water during the processing of minced meat products, which can not only retain the juice of raw meat, but also increase the taste and flavor of products , but also increase the yield of the product.

The water retention of protein is also affected by many factors, such as viscosity, pH value, ionization strength and temperature. Ma Yuxiang et al. studied the effect of the addition of soybean protein isolate on heat-induced gelation of salt-soluble muscle protein. The experimental results showed that: the addition of soybean protein isolate made the ultrastructure of the mixed protein gel rough and reduced the concentration of the mixed protein gel. strength, but the water holding capacity of the gel has been improved.

2. Emulsification
The hydrophilicity and lipophilicity of soybean protein determine its emulsification and stability. Soybean protein is a kind of surfactant, which can not only reduce the surface tension of water and oil, but also reduce the surface tension of water and air, so it is easy to form a more stable emulsion. The emulsified oil droplets are stabilized by proteins that accumulate on the surface of the oil droplets, forming a protective layer. This protective layer can prevent the aggregation of oil droplets and the destruction of the emulsified state, thereby stabilizing the emulsifying performance. In the production of baked food, frozen food and soup food, there have been a large number of research reports on adding soybean protein isolate as emulsifier to stabilize the product state.

3. Adhesion
The protein has a large molecular weight, strong solubility and adsorption capacity, making it cohesive. Suitable for adjusting the physical properties of food. When the protein is heated to 80°C, the protein dissociates or dissociates, the molecular specific volume increases, and the viscosity increases, and the viscosity above 90°C decreases instead. When the pH is between 6 and 8, the protein structure is the most stable and the viscosity is the largest; when the pH exceeds 11, the viscosity decreases sharply because the protein association is destroyed.

4. Gel
Meat products containing soybean protein will form a gel structure when heated. This feature can improve the hardness, elasticity, flakes and texture of meat products, and has a significant effect on the water retention and chewiness of the product. The formation of gel It is affected by many factors, including heating time, temperature and concentration of soybean protein solution.