In order to develop low-salt surimi, this study investigated the effect of the substitution of KCl and inosine 5’-monophosphate disodium salt (IMP) for sodium salt on the gel properties of surimi from silver carp. Three experimental groups were set up, namely, group A, added with 2% NaCl; group B, added with 0.8% KCl and 1.2% NaCl; and group C, added with 0.7% KCl, 0.1% IMP and 1.2% NaCl. To find out the optimal scheme of NaCl replacement, the whiteness, water-holding capacity, gel strength, texture profile analysis (TPA) parameters, water distribution and composition, and microstructure of surimi gels were tested. The results showed that compared to group B, whiteness, water-holding capacity and gel strength in group A decreased, hardness, adhesiveness, chewiness and cohesiveness decreased significantly, while elasticity did not change obviously; the proportion of immobile water decreased and the proportion of free water increased; the spatial structure of the gel network formed was incomplete. For group C, despite a significant decrease in chewiness, none of the other indicators significantly deteriorated, which indicates that KCl combined with IMP is an ideal substitute for NaCl.

Improving the digestibility of surimi products is key to boosting both their nutritional value and functional benefits. This study investigated how oxidized dihydromyricetin (oDMY) influences the digestion of silver carp surimi. Surimi gels were treated with four different concentrations of oDMY (0.15‰, 0.30‰, 0.45‰, and 0.60‰, m/m), and an in vitro digestion model was employed to analyze the resulting digestive fluids. Results demonstrated that the addition of 0.45‰ oDMY significantly enhanced the in vitro digestion of silver carp surimi. Key mechanisms for this enhancement include oDMY’s modulation on ionic and hydrogen bonding interactions within the protein network, which stabilizes the structure and facilitates protein breakdown during digestion. Additionally, 0.45‰ oDMY decreased the particle size of the digestion products, increasing trypsin accessibility and enhancing digestion efficiency. Furthermore, oDMY promoted the degradation of myosin heavy chain (MHC) during the intestinal digestion phase, leading to the release of more low-molecular-weight peptides. Specifically, 0.45‰ oDMY promoted the breakdown of the MHC, resulting in an elevated release of bioactive peptides. These findings indicate that oDMY could enhance protein digestion and boost the nutritional quality of surimi products.

The effects of salted duck egg white powder (SDEWP) and κ-carrageenan (KC) on autolysis and the properties of modori gel from threadfin bream surimi were investigated. The trichloroacetic acid-soluble peptide content (TCA-SPC) of surimi paste incubated at 65 °C for 60 min decreased significantly (P < 0.05) with the addition of more SDEWP. The decrease in TCA-SPC became lower in the samples incorporated with KC in a dose-dependent manner. Pastes containing SDEWP showed a more retained band of proteins with molecular weight of 45 kDa, while no change in protein pattern was observed when KC was added. The addition of SDEWP significantly improved the gel strength, water-holding capacity, and whiteness of the modori gel in a dose-dependent fashion. The more pronounced improvements in these parameters were observed when SDEWP was added in combination with 0.5 g/100 g KC. Modori gel showed significantly improved texture profiles when added with both SDEWP and KC. A denser and finer gel microstructure in modori gel was attained when added with both SDEWP and KC. Thus, SDEWP effectively prevented autolysis in surimi, while a combination of SDEWP and KC improved the gel properties of modori gel, in which maximal degradation of gel was induced by endogenous proteases.

In this study, the quality changes of prepared fish dish consisting of frozen-thawed bombay duck (Harpadon nehereus) and the spices green onion, garlic and ginger under modified atmosphere packaging (MAP) consisting of 60% CO₂ + 10% O₂ + 30% N₂ were examined during refrigerated storage at 4 ℃ for up to 12 days. Three groups were set up: control, MAP of fish and spices alone and together. The difference in quality preservation between the separate and combined MAP groups was examined. The results showed that MAP could effectively inhibit the increase in total volatile basic nitrogen (TVB-N) content and pH and the change in thiobarbituric acid reactive substance (TBARS) value, and suppress the degradation of inosine monophosphate (IMP) into hypoxanthine (Hx). This effect was more pronounced in the separate MAP group. Furthermore, MAP was able to effectively inhibit microbial growth in bombay duck with this effect being more pronounced in the separate MAP group. Also, MAP could reduce juice exudation and prevent the color from turning yellow, thereby improving the sensory quality of bombay duck. The separate MAP group showed higher scores for sensory attributes. Taken together, separate MAP of fish and spices allows better quality preservation of pre-prepared bombay duck dish.