Effect of Twin-Screw Extrusion on Water Absorption and Oil Retention of Soybean Protein

Extrusion machinery equipment for soybean protein processing equipment

Textured soybean protein has good water-holding and oil-absorbing properties, which can enhance the juiciness of food, reduce processing losses and greasiness, and give food a good taste. Adding an appropriate amount of textured soybean protein to quick-frozen dumpling fillings, meat products, imitation meat products, and vegetarian foods can replace part of chicken, beef, etc., without affecting the nutritional value and palatability of the food. Its water-holding capacity is an important indicator of its taste.

Water-holding capacity is related to the molecular composition, conformational state, hydrophilic strength of proteins, and the state of carbohydrates. It is influenced not only by covalent cross-linking but also by the ability of proteins to interact with water. During the extrusion puffing process, both conditioning and extrusion reduce the water-holding capacity of proteins, and this trend is affected by the critical value of free water content in the material. The water-holding capacity of products made by traditional extrusion puffing is higher than that of enzymatic extrusion puffing. On one hand, this may be due to starch gelatinization and the reduction of hydrophilic groups; on the other hand, it may be because the starch substrate indirectly inhibits the enzymatic hydrolysis of soybean protein. Since the extrusion process is a rather complex physicochemical process, the material undergoes complex physical and chemical reactions during texturization. Factors such as raw material characteristics, operating parameters, and the performance of puffing machinery all have a certain impact on the water absorption of the product.

In addition, products with strong oil absorption can provide consumers with more aromatic substances and a lubricating sensation, making them more easily accepted by consumers.