Analysis of digestive products of silver carp ( <i>Hypophthalmichthys molitrix</i> ) surimi gels after improving by different additives: In vitro and in vivo gastrointestinal digestion and absorption

The objective of this work was to investigate the impact of calcium hydrogen phosphate (CHP), curdlan gum (CUR), and TGase (TG) on the digestion and absorption of surimi gel. In this study, an In vitro digestion model combined with C57BL/6 mice was used to analyze digestive and absorbed juices comprehensively. The results showed that the addition of CHP and CUR surimi products showed a decreasing trend in the α-helix content in the secondary structure of substrate proteins after digestion, which slowed down the In vitro digestibility of surimi gel by 4.27% and 9.07% (p < 0.05). However, there was no significant difference in digestibility of surimi gel after TG addition compared with the control group. Digested surimi gel did not cause any nutritional loss. CUR can effectively control lipid accumulation in mice and improve their growth performance. All three additives can promote the release of peptides, and the small peptide content in the small intestinal chyme of the TG group significantly increased by 317.33 µg·mL^-1 (p < 0.05). This study provides a theoretical basis and guidance for producing surimi products with higher nutritional value.