Myofibrillar protein gel incorporated with soybean dietary fiber and sodium substitutes: Synergetic effect on gel properties and in vitro gastric digestion.

This study investigated the effect of sodium substitutes and soybean dietary fiber (SDF) on the gel properties and in vitro gastric digestion characteristics of myofibrillar protein (MP). Incorporation of sodium substitutes and SDF increased gel strength, particularly in gels with KCl. In contrast, CaCl and MgCl increased MP gel cooking loss, and SDF reduced this loss and improved water retention. CaCl and MgCl caused uniform microstructure of MP, and SDF led to a denser structure. Structural enhancements induced by SDF, such as stronger molecular interactions, denser gel structure and higher acid-buffering capacity of MP gel, decreased the pepsin diffusion rate and reduced protein hydrolysis. Notably, KCl combined with 3.0 % SDF further reduced the pepsin diffusion rate to 43.65 μm/s. Overall, the combination of sodium substitutes with SDF enhanced MP gel properties, retarded gastric acid diffusion, and retarded pepsin diffusion, resulting in lower hydrolysis degrees and larger molecular weight digestion products.