This study investigated the effect of ultrasound-assited cooking on the migration of nutritional components, flavor formation, and stability of Larimichthys crocea fillet soup. The results showed that ultrasonic assistance shortened the cooking time while improving the quality of the fish soup. The soup prepared with ultrasonic treatment for 80 min (U80) was comparable to that of the soup prepared by conventional cooking for 120 min (C120) in terms of taste, fat content, and whiteness. The fish soup prepared with ultrasonic treatment at 800 W for 120 min received a sensory score of 8.40 and an umami response value of 4.15, demonstrating optimal flavor quality. It was further found that high-intensity ultrasound (800 W, 120 min) did not significantly affect the dissolution of soluble proteins, nucleotides or oligopeptides, but significantly increased the contents of umami amino acids and fat by 3.85% and 29.09%, respectively, compared with the control. In addition, ultrasonic treatment effectively reduced the particle size of protein-lipid nanoparticles, increased the concentration of nanoparticles, and inhibited their agglomeration during the stewing process, thereby reducing the surface tension and friction coefficient of the soup system and enhancing its emulsion stability and smoothness. In conclusion, ultrasonic-assisted stewing shows application potential in enhancing the taste quality and stability of L. crocea fillet soup, offering an energy-efficient approach for the utilization and industrial processing of fish by-products.

This work aims to study the regulatory mechanism of calcium fortification on the texture of kelp pickle during the shelf-life period in order to provide theoretical support for improving its texture quality using exogenous calcium. The effects of fermentation acidity and sodium/calcium ratio on the texture of kelp pickle during its shelf life at 4 ℃ were studied, and the evolution of water distribution and the structure of calcium ion bridge was analyzed. The results showed the hardness of kelp pickle decreased with increasing fermentation acidity, but its changes were effectively slowed down by exogenous calcium lactate. The rate of hardness preservation of kelp pickle with a sodium/calcium of 1.5:1 increased by 92.8% compared with the control group. The results of scanning electron microscopy (SEM) and low-frequency nuclear magnetic resonance (NMR) spectroscopy showed calcium lactate alleviated the morphological damage of kelp tissues caused by acid produced during fermentation, and inhibited the transition of bound water to free water during the shelf-life period. The proportion of free water in kelp pickle with a sodium/calcium ratio of 2:1 increased by only 10.29 percentage points after six months of storage. The results of X-ray photoelectron spectroscopy (XPS) showed that the mechanism by which calcium lactate enhanced the texture of kelp pickle during its shelf-life might be related to the formation of a stable calcium ion bridge at a sodium/calcium ratio of 2:1 or 1.5:1.

The effect of nanosized bamboo dietary fiber (NBDF) on whey syneresis in yogurt during shelf storage was studied. The milk wettability of micro- and nano-modified NBDF with different particle sizes was analyzed. The inhibitory mechanism of the modified NBDF exhibiting the best milk wettability on whey syneresis during the shelf storage of yogurt was investigated. The results showed that the morphology of NBDF changed from blocky to filamentous after sequential ultrasound, pressurized heating and enzymatic hydrolysis. The microfibrils were fractured after high-energy mechanical ball milling, forming nanoclusters. The milk wettability of modified NBDF initially increased and then decreased with the decrease in particle size. The microfibrils with a particle size of 10–30 μm had the strongest milk wettability. Addition of the microfibrils at a mass concentration of 9 g/L improved the oscillation stability of set yogurt. After 28 days of shelf storage, the whey separation rate was 5.84%, which was only 57.87% of that of the control group. This may be related to the fact that the microfibrils effectively increased the proportion of bound water in yogurt (by 41.4%), improved the casein network structure, and increased the coatability, contributing to the formation of tiny and uniform whey pore channels in yogurt.