Application of Soybean Textured Protein in Food Industry

Soy protein is rich in nutrients, not only high in protein content, but also rich in eight essential amino acids required by the human body. The amino acid composition of its protein is incomparable to other proteins, and is an ideal vegetable protein. Its protein digestion and absorption rate is good, which is very similar to meat, but it will not cause obesity, cardiovascular disease, high cholesterol and other diseases like meat diet, and has obvious health care effects. And it is rich in calcium, phosphorus, iron and a variety of vitamins, especially the high content of B vitamins; it also contains essential potassium, sodium and other inorganic salts and trace elements, so it is more and more popular. There are many types of soy protein, including deodorized soy protein powder, defatted soy protein powder, soy protein concentrate, soy protein isolate, soy textured protein, etc. They have their own focus on functionality and price due to different processing techniques.

The defatted soybeans are extruded and expanded into tissue protein. The tissue protein has strong water absorption and oil absorption, and is similar to the fibrous tissue of lean meat. After rehydration, it has a certain degree of elasticity, toughness and chewing feeling; nutrition after processing The composition and form remain basically unchanged, and the price is low. Therefore, considering the use of soy tissue protein to replace part of the meat to make food is a new way to reduce production costs and improve product nutrition. 

1 Production principle and preparation process of textured soy protein

1.1 The production principle of textured soy protein 

Add low-temperature defatted soybean meal, high-temperature defatted soybean meal, cold-pressed soybean meal, concentrated protein, separated protein and other raw materials into a certain amount of water and additives, and mix them evenly, by mechanical or chemical methods, forcibly heating, pressurizing, and extrusion molding, Change the arrangement of protein molecules to produce a tissue structure in the same direction, and at the same time solidify to form fibrous protein that is soy tissue protein. The protein in the raw material can be undenatured or denatured. In the extruder, after the protein is pretreated, under the action of high temperature, high pressure and strong shearing force, the protein is denatured, the highly regular spatial arrangement inside the molecule changes, the secondary bonds in the protein molecule are destroyed, and the peptide bond structure Loose, and then form relatively linear protein molecular chains. These relatively linear protein molecular chains become more free at a certain temperature and moisture content, so that directional recombination is more likely to occur. In the process of protein denaturation, Affected by the directional force, the protein molecules are arranged linearly and organized along the flow direction, and further solidify to form a fleshy fiber structure. Finally, the temperature and pressure are drastically changed through the mold to produce a certain expansion to form porous tissue protein.

1.2 Main production process requirements

(1　 Selection of raw materials: raw materials have a greater impact on the puffing technology, so the selection of raw materials is very important. Generally, it is required that the protein content of the raw materials is greater than 50%, the fat content is less than 1.5%, the fiber content is less than 3.5%, the moisture content is less than 10%, and the nitrogen The solubility coefficient (NSI) is about 60%. 

(2　PH adjustment: The pH value of the raw material should be around 7.0. When the pH value is lower than 5, the degree of organization will drop sharply, and it will not even expand; with the increase of the pH value, the product will be slightly alkaline. The quality of the organization is better, and the shape is neat. When the PH value is above 8, the product becomes brittle and hard, and produces peculiar smell and toxic substances, and the color is poor. 

(3　Temperature: temperature and material-water ratio temperature at 190℃, material-water ratio 20:13-15 conditions, the water absorption rate is the largest, the shear force is the largest, the higher the water absorption rate, the higher the elasticity and toughness of the soy tissue protein; The greater the shearing force, the better the degree of organization, and the better the product forming degree, the bright yellow color is uniform. 

2 Textured soy protein composition and physical and chemical indicators 

The appearance is light yellow or yellow-brown, the surface color is uniform, block or granular, no bitterness, no hardness, elasticity, water absorption and oil absorption, porous sponge shape, etc., slightly bey, swelling after absorbing water On the surface of the water, it does not fall apart and has a fibrous tissue structure similar to lean meat. Its main components and physical and chemical indexes are shown in Table 1. 

3 Application of textured soy protein in food industry 

3.1 Application in meat products: Textured soybean protein has good water absorption and oil retention. When added to meat products, it can increase the color, aroma, taste and protein content of meat products, and can promote the integrity of the particles and the yield It is improved, so it is an ideal meat product additive, and it can be added to meat products to reduce the amount of lean meat added. For example, in the meat sausage, adding the soy protein within 15% of the meat weight can maintain the appearance and quality of the product; in the meatball, adding the soy protein within 20% of the meat weight, the taste and taste are better than pure meatballs ; In the filling of pie and dumplings, adding soy protein within 30% of the meat weight, the quality and flavor are improved, which not only reduces the production cost, but also increases the protein content.

3.2 Application in convenience foods: Textured soybean protein has the characteristics of imitating meat texture, and can be made into convenience foods with various flavors. Silky and flaky protein products are directly used to make vegetarian imitation meat foods, lumpy and small Granules can be used to make various fillings, which not only satisfy people's senses, but also provide high-quality protein sources. It can be eaten after soaking in hot water, and can be used as breakfast and lunch for school-age children.

3.3 Application in dishes: After hydration in production, the soy protein has uniform tissue characteristics and specific tissue structure, and has good chewiness and meat texture. It is suitable for frying, frying, cooking, frying, soup, and cooking. Both filling and cold dressing are acceptable. In minced meat or other meat products, add 25-50% tissue protein and mix with various seasonings to make dishes that have the taste of meat. Therefore, it can be used to partially replace meat. Soy tissue protein is a real high-quality and cheap food .

3.4 Application in leisure food: The tissue protein has a good granular structure. After processing, it can be made into various flavors of dried meat, preserves, vegetarian food, etc. During the process of processing the tissue protein, different flavors can be seasoned. Adding the agent to leisure foods can produce leisure foods with different flavors, rich nutrition and excellent taste.

3.5 Application in nutritious health food: Soy protein is not only high in nutritional value, but also an excellent health food, suitable for all ages. It is an auxiliary curative food for patients suffering from cardiovascular disease, arteriosclerosis, diabetes, high blood pressure, high cholesterol, hepatitis, nephritis, and obesity.

4 Conclusion:

To sum up, the soy protein has rich nutritional value, natural physiological and health care functions, excellent production and processing characteristics, and extensive economic benefits. It is a very promising functional food material. Moreover, at present, my country Animal protein resources are lacking, and protein intake is generally lower than the level required to maintain human health every day. New protein sources are urgently needed to make up for this deficiency. my country is rich in soybean resources. Soy food is the inevitable trend of food development in the future and has broad market prospects.