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.

This study mainly investigated the antifreeze efficiency of various glycosylated fish gelatin hydrolysates (GPs) on the storage quality of shrimp surimi gels (SSGs) during frozen storage. Glycosylated fish gelatine hydrolysate and commercial antifreeze were found to increase the brightness and whiteness of minced shrimp gels during freezing and storage and to reduce a* and b*. It was found that the addition of glycosylated GPs effectively improved the color, texture, and rheological properties of SSGs while inhibiting protein oxidation. Among the tested GPs and commercial antifreeze, ribose glycosylated GP (RGP) exhibited the highest antifreeze properties. Moreover, RGP significantly exhibited strong antimicrobial properties against Hivarius spp. and Pseudoalteromonas spp. In conclusion, RGP has the potential to replace traditional commercial cryoprotectant and offers a new strategy for preserving aquatic products.

This study comparatively analyzed the effects of water bath (WB) and ultrasonic-assisted water bath (UWB) extraction at different pH conditions on the extraction kinetics, gelling properties, rheological properties, and structural properties of grass carp fish scale gelatin. Results indicated that the gel strength of fish scale gelatin extracted by UWB was greater than that obtained by WB at pH more than 7.0. The rheological results demonstrated that UWB elevated the apparent viscosity of fish scale gelatin, but decreased the gelling and melt points. The results of structural analysis indicated that UWB resulted in a reduction in the content of α-helix and β-sheet in fish scale gelatin. Furthermore, both pH and UWB were found to alter the tertiary structure of fish scale gelatin. This study may provide novel ideas for the high-value comprehensive utilization of fish scale waste.