With the changes in lifestyle in recent years, the number of prepared meat products is quietly increasing, ranging from various semi-finished fried chicken nuggets, seasoned meat steaks and barbecue products, to the staple products of convenience stores such as skewers and bento. Through retail terminals, prepared meat products are increasingly infiltrating the household consumption of the Chinese public, and have gradually become a consumption trend. In the development of conditioned meat products, soy protein is a commonly used additive, which can not only supplement the essential amino acids needed by the human body, but also have good functional properties such as foaming, emulsifying and gelling properties, so it can significantly improve The taste of food, increase the elasticity, oil and water retention of food, improve the storage performance of food, etc. At the same time, it can reduce the production cost and play an important role in the processing of prepared meat products.
1. Classification of soy protein
1.1 Soy flour
Soybean flour is mostly “defatted and deodorized soybean”, which is cheap because of its low protein content. When used in meat products, it can keep 2 times its own weight of water, and the soybean flour emulsion can keep the same weight of fatty substances without oil during thermal processing. Soybean flour has poor functionality, has many defects in taste and flavor, and is limited in scope and amount of use.
The protein content of soy protein concentrate is about 70%, and most of them are used in meat products. The emulsification-gel ratio of soybean protein concentrate is protein:water:fat=1:4:3, which can be used in meat products to improve the taste and structure and increase the protein content of the product.
Soy protein isolate is a protein produced from low-temperature desolubilized soybean meal. Among them, the protein content is more than 90%, and there are nearly 20 kinds of amino acids, and it contains essential amino acids. It is rich in nutrients and contains no cholesterol, and is widely used in conditioning meat products.
Textured soy protein is a product made from defatted soybean flour, soybean protein concentrate or soybean protein isolate, etc., under the action of mechanical and thermal processes such as stirring, extrusion, and puffing. Such proteins have a certain meat-like chewiness. Therefore, the application in conditioning meat has a special application, which can replace some lean meat raw materials.
2. Functional properties and functions of soybean protein
2.1 Water retention
The water retention of soy protein plays an important role in the production of meat products, especially the ability to absorb, bind and bind water during the processing of minced meat products, which can not only retain the juice of the raw meat, but also increase the taste and flavor of the products. , but also increase the yield of the product.
The water retention of proteins is also affected by many factors, such as viscosity, pH, ionization strength and temperature. Ma Yuxiang et al. studied the effect of the addition of soybean protein isolate on the heat-induced gelation of salt-solubilized 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 mixed protein gel. strength, but the water-holding capacity of the gel is improved.
The hydrophilic and lipophilic properties of soybean protein determine its emulsifying and stable properties. Soybean protein is a surfactant, it can 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 kind of protective layer. This protective layer prevents the aggregation of oil droplets and the destruction of the emulsified state, thereby stabilizing the emulsification performance. In the production of baked food, frozen food and soup food, there have been a lot of research reports on adding human soy protein isolate as emulsifier to stabilize the state of the product.
Proteins have large molecular weight, strong solubility and adsorption capacity, making them cohesive. It is suitable for adjusting the physical properties of food. When the protein is heated to 80 ℃, the protein will dissociate or dissociate, the molecular specific volume will increase, and the viscosity will increase, and the viscosity will decrease when the temperature exceeds 90 ℃. 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.
Meat products containing soy protein will form a gelatinous structure when heated. This characteristic can improve the hardness, elasticity, sheeting and texture of meat products, and has a significant effect on the water retention and chewing feel of the product. The formation of gel Affected by many factors, including heating time, temperature and soy protein concentration.
3. Application of soy protein in conditioning meat products
Soy protein contains essential amino acids for the human body, which can strengthen the nutritional content of conditioned meat products and play an important role in improving the quality of conditioned meat products.
3.1 A cost-effective protein source for enhanced nutrition
Soy protein has been widely used in prepared meat products due to its low price and good protein quality. Adding soy protein to various quick-frozen meat products can not only improve the ratio of protein, but also make the nutrition of protein more comprehensive. , more reasonable.
3.2 Seasoning effect in conditioning meat products
Soy protein contains a small amount of fatty acids and carbohydrates, which will produce a unique aroma of beans after heating, and some unpleasantness caused by raw meat (such as fish meat) or auxiliary materials and some unpleasantness caused by processing technology (such as sterilization) in prepared meat products Odor may cause disgust among consumers. The unique aroma of soybean protein has a certain masking effect on the above odor, so soybean protein has a certain flavoring effect.
3.3 Soy protein can improve the structure of conditioned meat products
Soy protein has good gel properties and bonding properties, which can effectively improve the structure of the product, enhance the elasticity and hardness of the product, and make the product denser in structure, better in taste and more fleshy. powerful. Especially in the quick-frozen meat skewers, pork balls and minced meat products, the role is more prominent.
3.4 Utilize the emulsification of soybean protein to solve the problem of water and oil production in conditioning meat products
Water and oil are one of the most common problems in the cooking process of conditioned meat products. Using the emulsification properties of soybean protein, water and oil can form a relatively stable network structure, so that the water and oil in conditioned meat products will not be released. , In the process of storage and cooking, the phenomenon of water and oil production is reduced.
4. The use of soy protein
Two important technological processes in the processing of conditioned meat products are the processing of raw meat and the marinating of ingredients. According to the processing characteristics of conditioned meat products, the addition methods usually include the following:
4.1 Injection method
For large pieces of fresh meat, add people with the method of injecting pickling liquid. That is, the soybean protein is dissolved in the brine of the pickling liquid and added by injection, and then other processing techniques are carried out. This method can make the protein evenly distributed in the meat. In general, soy protein accounts for 2% to 6% of the weight of meat products.
4.2 Dry method
That is, the soybean protein product is added evenly in the state of dry material at the beginning of the chopping, rolling and stirring processes, but the dry material should be added to the meat product before the fat.
4.3 Hydration method
In order to make full use of the functional properties of soybean protein, it is best to hydrate the soybean protein product before adding it, and use it as a dispersion containing about 18% protein. The ratio of water is 1: (1.5-1.8) for soybean flour: water, 1: (2-2.5) for protein concentrate: water, and 1: (3.5-4) for protein isolate: water.