Formation and characterization of acid‐soluble soybean protein with chitosan addition: effects of hydrothermal treatment and homogenization

Abstract BACKGROUND The development of acid‐soluble soybean protein (ASSP) is a dynamic field with ongoing research aimed at exploring its emulsifying, foaming, and gelling properties. These properties can affect the texture, stability, and sensory attributes of food. Innovations in processing technologies, such as freeze‐drying, hydrothermal treatment, and homogenization processing, are being made to enhance the quality of ASSP, which are crucial for its application in food products. RESULTS The complex coacervates formed by soybean protein isolate (SPI) and chitosan (CS) exhibited superior stability. Visually, the properties were explored by the effect of pH, protein–polysaccharide complex ratio, and ionic strength on the stability of the ASSP system. The results showed that CS improved the solubility of ASSP and its effectiveness in drinks with pH 3.2. Additionally, the comparative treatment performed by ASSP through hydrothermal treatment exhibited higher stability and complex solubility than that of homogenization. CONCLUSION Overall, the SPI–CS complex can be formed by hydrothermal treatment and homogenization on biopolymer solutions and at fitting pH values in an acid‐soluble system. Both of them changed the secondary structure of protein and formed a new protein spatial conformation. This will provide a theoretical basis for the practical application of acid drinks, which has a promising future in the field of novel food development. © 2025 Society of Chemical Industry.