Effects of different plant polysaccharides as fat substitutes on the gel properties, microstructure and digestion characteristics of myofibrillar protein

This study aimed to investigate the effects of different plant polysaccharides (inulin, κ-carrageenan, and konjac glucomannan) as fat substitutes on the gel properties, microstructure, and digestion characteristics of myofibrillar protein (MP). The results revealed that incorporating inulin, κ-carrageenan, and konjac glucomannan significantly improved the water holding capacity, texture profiles, and rheological behavior of MP gels while limiting water fluidity. Among them, the MP-konjac glucomannan gel (1%, w/w) showed superior water retention and gel strength, demonstrating the most notable restriction on water translocation. Microstructural analysis observed that the MP gels with inulin, κ-carrageenan, and konjac glucomannan displayed a dense and well-clustered network structure, resulting in a more even distribution and compact gel structure. However, including 1.5% and 2% konjac glucomannan in MP mixed gels resulted in block-like clustering and larger agglomeration. Furthermore, the protein digestibility assessment indicated that polysaccharides incorporation significantly reduced the digestibility of MP, with konjac glucomannan demonstrating higher digestibility compared to inulin and κ-carrageenan groups. Overall, incorporating konjac glucomannan at a 1% incorporation (w/w) can effectively serve as a fat substitute in muscle food. This study will provide valuable insights for utilizing konjac glucomannan as a fat substitute in meat products.