Effects of Egg White Protein and Konjac Glucomannan on the Digestion and Fermentation Properties of Trachypenaeus curvirostris Surimi Gel

This study examined the effects of egg white protein (EWP) and konjac glucomannan (KGM) on the digestion and fermentation properties of shrimp (Trachypenaeus curvirostris) surimi gel (SSG) using in vitro models. The results showed that the in vitro protein digestibility of the SSG-EWP group increased first and then decreased with the increase in EWP concentration, and EWP increased the generation of peptides during SSG digestion. SSG with 4% added EWP had the highest in vitro digestibility, while neither the in vitro protein digestibility nor the peptide release of SSG was significantly influenced by KGM (P > 0.05). EWP and KGM increased the contents of essential amino acids in the digestion products of SSG. Antioxidant assay showed that EWP improved the Fe²⁺ chelating capacity of the digestion products, but decreased the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. KGM increased the antioxidant activity of the digestion products in terms of both Fe²⁺ chelating capacity and DPPH radical scavenging capacity. Furthermore, gut microbiome study revealed that EWP played a more positive role in maintaining gut microbial diversity and regulating beneficial bacteria than KGM. Clusters of Orthologous Groups (COG) metabolic pathway analysis indicated 24 major metabolic pathways of intestinal microbes, mainly involving the transport and metabolism of carbohydrates, amino acids and other substances. This study provides technical guidance for the preparation of high-quality T. curvirostris surimi gel.