In this work, nano fish bone (NFB) was prepared from silver carp bones and added to silver carp myosin. The speciation changes and distribution of calcium in NFB (NFB-Ca) during myosin gelation were investigated by measurement of various calcium species, surface element analysis, microstructure examination and low-filed nuclear magnetic resonance (LF-NMR). Results showed that the Ca content of myosin with the addition of NFB significantly increased compared to that without added NFB. NFB-Ca existed mainly in an insoluble form in myosin (> 95%). Heating treatment at 40 ℃ significantly increased the ionic Ca content; however, ionic-Ca was transformed into other forms at 90 ℃. Therefore, it was suggested that part of the soluble Ca released from NFB participated in the formation of salt bridges and consequently was transformed into insoluble calcium, facilitating myosin cross-linking. As a result, a continuous and uniform gel network structure was observed under laser confocal scanning microscopy (LCSM). Meanwhile, LF-NMR showed that the compact microstructure could help to hold more water and decrease water mobility. In addition, the surface Ca of myosin with NFB increased, and the distribution uniformity of Ca was improved after heating treatment.

In the present study, the effect of high intensity ultrasound (HIU) on the physicochemical properties of silver carp myosin with different salt concentrations (0.1, 0.2, 0.3, 0.5, 1.0, 2.0 mol/L NaCl) was investigated in terms of solubility, particle size distribution, static rheological properties, and microscopic morphology. The changes in physicochemical properties of myosin induced by HIU were affected by salt concentrations. At low salt concentration (0.1 mol/L), HIU obviously disrupted the structure of myosin filaments, resulting in decreased particle size and zero shear viscosity, and increased fluidity. Moreover, the solubility of HIU treated myosin with low salt concentration was increased about ten times compared to the untreated control with the same salt concentration, while it was close to that of the untreated control with 0.2 mol/L NaCl. For myosin with medium and high NaCl concentrations (0.5 and 1.0 mol/L), the solubility was better than that with low salt concentration. HIU could induce conformational changes in myosin, resulting in exposure of reactive groups and a further increase in the solubility. However, HIU was less effective in increasing the solubility of myosin at medium and high than at low salt concentrations. In summary, HIU can improve the physicochemical properties of myosin more at low than at medium and high salt concentrations, which might provide a theoretical basis for the production of low-salt surimi products.

In this study, fresh fish vermicelli was made from surimi and starch using a cutting process. The effects of ultrasonic pretreatment at different powers (120, 150, 180, 240 and 300 W) for different periods (5, 10, 15, 20 and 25 min) on the cooking quality, sensory quality and texture characteristics of fresh fish vermicelli were explored. The underlying mechanism was clarified by measuring the particle size and viscosity of the paste as well as the infrared spectrum, moisture distribution and microstructure of the vermicelli. The results showed that with the increase in ultrasonic power and time, the particle size and viscosity of the paste initially decreased and then increased, while the opposite trend was observed for the percentage of bound water (A₂₁). Decreased ultrasonic time and power improved the dispersion and uniformity of raw materials, increased the water-binding capacity, and promoted fish vermicelli to form a uniform and dense microstructure. Increased ultrasonic time and power caused protein degradation, reduced the microstructural uniformity of fresh fish vermicelli, and deteriorated its quality. Ultrasonic treatment at 120 W for 10 min increased the tensile strength and stretching distance of fresh fish vermicelli increased by 23.98% and 21.08%, respectively, and decreased the broken rate and grout vomiting value decreased by 28.27% and 11.54%, respectively, compared with the control group without ultrasonic treatment. Under this ultrasonic condition, fish vermicelli had the highest sensory score.

NaCl is an essential component of salting ingredients, and NaCl diffusion in aquatic animal muscles significantly influences the microbiology, texture and flavor of aquatic products. Consequently, in order to improve the salting efficiency and product quality, researchers have made extensive efforts on how to control and predict the diffusion of NaCl during the salting process. This paper introduces the current simulation methods of NaCl diffusion from three perspectives: theoretical model, predictive model and finite element analysis. It provides a comprehensive overview of the current status of the application of the three simulation methods as well as their advantages and disadvantages in the salting process of aquatic products. This review aims to provide theoretical and technical references for the innovative development and intelligent production of salted aquatic products.

The objective of study was to investigate the softening effect and mechanism of Garcinia gummi-gutta on grass carp bones. The pattern of change in the hardness of grass carp bones was studied during pickling using a G. gummi-gutta juice-based marinade at different temperatures (5, 10, 25, and 40 ℃). At the same time, changes in the composition and structure of grass carp bones and in the acidity and pH of the marinade were also determined. The results showed that the hardness of grass carp bones gradually decreased with pickling time, which decreased by 71.5%–79.4% after 25 days of pickling (P < 0.05). The ash content decreased by 11.90%–16.65% (P < 0.05), and the moisture content by 4.23%–13.08% (P < 0.05). The dense and ordered microstructure became loose and porous. This was because the reaction of H⁺ with hydroxyapatite in fish bones enabled calcium to be dissolved from fish bones and the consumption of H⁺ in the pickling solution decreased its acidity and increased its pH. Malic acid was played a major role in softening fish bones. Infrared spectroscopic analysis showed that the triple helix structure of fish bone collagen was not destroyed, but the absorption peak corresponding to amide A shifted to a higher wavenumber, suggesting a reduction in the number of hydrogen bonds, which might be related to the loss of hydroxyapatite in fish bones.