In the development of processed meat products, soy protein is a commonly used additive. It not only supplements essential amino acids required by the human body but also has excellent functional properties such as foaming, emulsifying, and gelling abilities. Therefore, it can significantly improve the texture of food, increase its elasticity, oil-holding capacity, and water-holding capacity, enhance the storage performance of food, and reduce production costs. It plays an important role in the processing of processed meat products.
I. Classification of Soy Protein
1. Soy Flour: Most soy flour is "defatted and deodorized soybean", and due to its low protein content, it is relatively inexpensive. When used in meat products, it can retain twice its own weight in water. Soy flour emulsions can prevent fat from leaking out during thermal processing. However, soy flour has poor functional properties, and its taste and flavor have many shortcomings. Its application range and usage are thus limited.
2. Soy Concentrate: Soy concentrate has a protein content of about 70% and is mostly used in meat products. The emulsifying gel ratio of soy concentrate is protein: water: fat = 1:4:3. When used in meat products, it improves the texture and structure and increases the protein content of the product.
3. Soy Isolate: Soy isolate is a type of protein produced from low-temperature desolventized soy meal. It has a protein content of over 90% and contains nearly 20 types of amino acids, including essential amino acids for the human body. It is rich in nutrients and free of cholesterol, and is widely used in processed meat products.
4. Textured Soy Protein: Textured soy protein is a product made from defatted soy flour, soy concentrate, or soy isolate through mechanical and thermal processes such as stirring, extrusion, and puffing. This type of protein has a certain meat-like chewiness. Therefore, it has a special application in processed meat products and can replace some lean meat ingredients.
II. Functional Properties
1. Water-Holding Capacity: The water-holding capacity of soy protein refers to its ability to absorb, bind, and retain water during the processing of meat emulsion products. It not only retains the juice of raw meat but also enhances the taste and flavor of the product and increases the yield. The water-holding capacity of protein is also affected by many factors, such as viscosity, pH, ionic strength, and temperature.
2. Emulsifying Capacity: The hydrophilic and lipophilic nature of soy protein determines its emulsifying and stabilizing properties. Soy protein is a surfactant that can reduce the surface tension between water and oil as well as between water and air, thus easily forming a stable emulsion. The oil droplets are stabilized by the proteins gathered on their surface, forming a protective layer. This protective layer prevents the aggregation of oil droplets and the disruption of the emulsified state, thereby maintaining the stability of the emulsion. There are numerous research reports on the addition of soy isolate as an emulsifier in baked goods, frozen foods, and soups to stabilize the product state.
3. Adhesive Properties: Due to its large molecular weight and strong solubility and adsorption capacity, soy protein has adhesive properties. It is suitable for adjusting the physical properties of food. When heated to 80°C, proteins undergo dissociation or precipitation, increasing the molecular volume and viscosity. However, when heated above 90°C, the viscosity decreases.
The protein structure is most stable and has the highest viscosity at pH 6-8. When the pH exceeds 11, the viscosity drops sharply because protein associations are disrupted.
4. Gelation: When meat products containing soy protein are heated, they form a gel structure. This property can improve the hardness, elasticity, sliceability, and texture of meat products, and has a significant effect on the water-holding capacity and chewiness of the products. The formation of gel is influenced by various factors, including heating time, temperature, and the concentration of soy protein solution.
III. Application in Processed Meat Products
1.Soy protein contains essential amino acids for the human body, which can enhance the nutritional content of processed meat products. At the same time, it plays an important role in improving the quality of processed meat products. 1. Soy protein, a cost-effective protein source with enhanced nutrition, has been widely used in processed meat products due to its low price and high-quality protein. Adding soy protein to various frozen meat products not only improves the protein ratio but also makes the protein nutrition more comprehensive and reasonable.
2. The flavoring effect of soy protein in processed meat products: Soy protein contains a small amount of fatty acids and carbohydrates. After heating, it produces a unique bean aroma. Sometimes, the raw meat (such as fish meat) or the auxiliary materials in processed meat products, as well as the unpleasant odors produced by processing techniques (such as sterilization), may cause consumers' aversion. The unique aroma of soy protein can mask these odors to a certain extent, thus giving it a certain flavoring effect.
3. Soy protein can improve the structure of processed meat products: Soy protein has good gelation and binding properties. By taking advantage of these properties in the processing of processed meat products, the structure of the product can be effectively improved, enhancing its elasticity and hardness, making the structure more compact, and improving the taste and meaty texture. This effect is particularly prominent in frozen meat skewers, pork balls, and meat paste products.
4. Utilizing the emulsifying property of soy protein to solve the problem of water and oil leakage in processed meat products: Water and oil leakage are one of the most common problems during the cooking process of processed meat products. By taking advantage of the emulsifying property of soy protein, a relatively stable network structure can be formed between water and oil, preventing them from separating out during storage and cooking, thereby reducing the phenomenon of water and oil leakage.
IV. Usage Methods
There are two important processing procedures in the production of processed meat products: processing of raw meat and seasoning and marinating. According to the processing characteristics of processed meat products, there are usually the following methods of addition:
1. Injection method: For large pieces of fresh raw meat, the soy protein is added by injecting the marinade solution. That is, the soy protein is dissolved in the salt water of the marinade and injected into the meat, followed by other processing procedures. This method can ensure the uniform distribution of the protein in the meat. Generally, the soy protein accounts for 2% to 6% of the weight of the meat product.
2. Dry method: The soy protein product is evenly added in the form of dry powder at the beginning of the chopping, tumbling, and stirring processes. However, the dry powder should be added before the fat.
3. Hydration method: To fully utilize the functional properties of soy protein, it is best to hydrate the soy protein product before adding it, making a dispersion with about 18% protein content for use. The water ratio is 1: (1.5 to 1.8) for soy flour and water, 1: (2 to 2.5) for concentrated protein and water, and 1: (3.5 to 4) for isolated protein and water.
I. Classification of Soy Protein
1. Soy Flour: Most soy flour is "defatted and deodorized soybean", and due to its low protein content, it is relatively inexpensive. When used in meat products, it can retain twice its own weight in water. Soy flour emulsions can prevent fat from leaking out during thermal processing. However, soy flour has poor functional properties, and its taste and flavor have many shortcomings. Its application range and usage are thus limited.
2. Soy Concentrate: Soy concentrate has a protein content of about 70% and is mostly used in meat products. The emulsifying gel ratio of soy concentrate is protein: water: fat = 1:4:3. When used in meat products, it improves the texture and structure and increases the protein content of the product.
3. Soy Isolate: Soy isolate is a type of protein produced from low-temperature desolventized soy meal. It has a protein content of over 90% and contains nearly 20 types of amino acids, including essential amino acids for the human body. It is rich in nutrients and free of cholesterol, and is widely used in processed meat products.
4. Textured Soy Protein: Textured soy protein is a product made from defatted soy flour, soy concentrate, or soy isolate through mechanical and thermal processes such as stirring, extrusion, and puffing. This type of protein has a certain meat-like chewiness. Therefore, it has a special application in processed meat products and can replace some lean meat ingredients.
II. Functional Properties
1. Water-Holding Capacity: The water-holding capacity of soy protein refers to its ability to absorb, bind, and retain water during the processing of meat emulsion products. It not only retains the juice of raw meat but also enhances the taste and flavor of the product and increases the yield. The water-holding capacity of protein is also affected by many factors, such as viscosity, pH, ionic strength, and temperature.
2. Emulsifying Capacity: The hydrophilic and lipophilic nature of soy protein determines its emulsifying and stabilizing properties. Soy protein is a surfactant that can reduce the surface tension between water and oil as well as between water and air, thus easily forming a stable emulsion. The oil droplets are stabilized by the proteins gathered on their surface, forming a protective layer. This protective layer prevents the aggregation of oil droplets and the disruption of the emulsified state, thereby maintaining the stability of the emulsion. There are numerous research reports on the addition of soy isolate as an emulsifier in baked goods, frozen foods, and soups to stabilize the product state.
3. Adhesive Properties: Due to its large molecular weight and strong solubility and adsorption capacity, soy protein has adhesive properties. It is suitable for adjusting the physical properties of food. When heated to 80°C, proteins undergo dissociation or precipitation, increasing the molecular volume and viscosity. However, when heated above 90°C, the viscosity decreases.
The protein structure is most stable and has the highest viscosity at pH 6-8. When the pH exceeds 11, the viscosity drops sharply because protein associations are disrupted.
4. Gelation: When meat products containing soy protein are heated, they form a gel structure. This property can improve the hardness, elasticity, sliceability, and texture of meat products, and has a significant effect on the water-holding capacity and chewiness of the products. The formation of gel is influenced by various factors, including heating time, temperature, and the concentration of soy protein solution.
III. Application in Processed Meat Products
1.Soy protein contains essential amino acids for the human body, which can enhance the nutritional content of processed meat products. At the same time, it plays an important role in improving the quality of processed meat products. 1. Soy protein, a cost-effective protein source with enhanced nutrition, has been widely used in processed meat products due to its low price and high-quality protein. Adding soy protein to various frozen meat products not only improves the protein ratio but also makes the protein nutrition more comprehensive and reasonable.
2. The flavoring effect of soy protein in processed meat products: Soy protein contains a small amount of fatty acids and carbohydrates. After heating, it produces a unique bean aroma. Sometimes, the raw meat (such as fish meat) or the auxiliary materials in processed meat products, as well as the unpleasant odors produced by processing techniques (such as sterilization), may cause consumers' aversion. The unique aroma of soy protein can mask these odors to a certain extent, thus giving it a certain flavoring effect.
3. Soy protein can improve the structure of processed meat products: Soy protein has good gelation and binding properties. By taking advantage of these properties in the processing of processed meat products, the structure of the product can be effectively improved, enhancing its elasticity and hardness, making the structure more compact, and improving the taste and meaty texture. This effect is particularly prominent in frozen meat skewers, pork balls, and meat paste products.
4. Utilizing the emulsifying property of soy protein to solve the problem of water and oil leakage in processed meat products: Water and oil leakage are one of the most common problems during the cooking process of processed meat products. By taking advantage of the emulsifying property of soy protein, a relatively stable network structure can be formed between water and oil, preventing them from separating out during storage and cooking, thereby reducing the phenomenon of water and oil leakage.
IV. Usage Methods
There are two important processing procedures in the production of processed meat products: processing of raw meat and seasoning and marinating. According to the processing characteristics of processed meat products, there are usually the following methods of addition:
1. Injection method: For large pieces of fresh raw meat, the soy protein is added by injecting the marinade solution. That is, the soy protein is dissolved in the salt water of the marinade and injected into the meat, followed by other processing procedures. This method can ensure the uniform distribution of the protein in the meat. Generally, the soy protein accounts for 2% to 6% of the weight of the meat product.
2. Dry method: The soy protein product is evenly added in the form of dry powder at the beginning of the chopping, tumbling, and stirring processes. However, the dry powder should be added before the fat.
3. Hydration method: To fully utilize the functional properties of soy protein, it is best to hydrate the soy protein product before adding it, making a dispersion with about 18% protein content for use. The water ratio is 1: (1.5 to 1.8) for soy flour and water, 1: (2 to 2.5) for concentrated protein and water, and 1: (3.5 to 4) for isolated protein and water.
