Huamao Wei

The large yellow croaker (Larimichthys crocea) is a high-value marine fish, but stress during live transport often leads to physiological disturbance and deterioration of muscle quality. This study investigated the effects of pre-transport temporary rearing at three temperatures (8, 10, and 12 °C) over 48 h on stress response, energy allocation, and muscle quality in this fish species. Temporary rearing at 8 °C induced stronger cold stress, characterised by elevated cortisol, marked lipid mobilisation, late lactate rebound, and greater loss of polyunsaturated fatty acids, indicating enhanced stress–catabolism coupling and higher risk of quality deterioration. In contrast, 12 °C did not sufficiently suppress metabolic turnover, resulting in continuous glycogen depletion, rapid ATP degradation, and accelerated accumulation of bitter-tasting nucleotide metabolites such as hypoxanthine. Among the tested temperatures, 10 °C showed the most coordinated response, with relatively stable endocrine status, moderate substrate utilisation, lower accumulation of undesirable degradation products, and better preservation of texture, water-holding capacity, and flavour-related precursors. These findings suggest that 10 °C is a promising pre-transport temporary rearing temperature for large yellow croakers under the present 48 h experimental conditions. The advantage of this temperature appears to lie in achieving a more favourable balance between metabolic suppression and physiological homeostasis, thereby providing a scientific basis for improving pre-transport rearing management and supporting safer, more stable live transport. Future studies incorporating behavioural and molecular indicators are needed to further clarify the regulatory effects of 10 °C during pre-transport rearing.

The aim of this study was to investigate the effect of neutral protease treatment on the biochemical properties of various parts of Pacific oysters (Crassostrea gigas) under different storage conditions. The mechanism of quality degradation in the mantle, adductor muscle, gill, and trunk of treated oysters stored at −1.5 °C (superchilling) or 4 °C (refrigeration) for several days using different storage methods was studied. The results showed that the oyster treated with the enzyme exhibited higher glycogen content, flavor nucleotide content, and sensory scores compared to the control group. Superchilling at −1.5 °C was observed to slow the increase in total volatile basic nitrogen (TVB-N), total viable count (TVC), and pH, while maintaining sensory scores better than refrigeration at 4 °C. Both wet superchilling (WS) and dry exposed superchilling (DeS) methods effectively preserved freshness and quality at −1.5 °C. The freshness of the oysters’ body trunk changed most significantly. K value, K′ value, and AEC value, as the evaluation indexes of oyster freshness, were affected by the storage medium. Therefore, neutral protease enhances the flavor of oysters in a short time, and oysters stored in wet superchilling or dry exposed superchilling conditions have an extended shelf life.

BACKGROUND: In order to improve the tenderness of dried shrimp products as well as to reduce the hardness of the meat during the drying process, shrimp were treated with ultrasound combined with pineapple protease and the tenderization condition was optimized by measuring the texture and shear force of dried shrimp. In addition, the sulfhydryl content, myofibril fragmentation index (MFI) and microstructure were also examined to clarify the mechanisms of shrimp tenderization.RESULTS: The results showed UB1 group with ultrasonic power of 100 W, heating temperature of 50 °C and pineapple protease concentration of 20 U mL⁻¹ were the optimum tenderization conditions, where shrimp showed the lowest hardness (490.76 g) and shear force (2006.35 gf). Microstructure as well as sodium dodecyl sulfate–polyacrylamide gel electrophoresis results suggested that during the tenderization process the muscle segments of shrimps were broken, degradation of myofibrillar proteins occurred, and MFI values and total sulfhydryl content increased significantly (P < 0.05) (MFI value = 193.6 and total sulfhydryl content = 93.93 mmol mg⁻¹ protein for UB 1 group).CONCLUSION: Ultrasound combined with bromelain could be used as a simple and effective tenderization method for the production of tender dried shrimp. The best conditions were 100 W ultrasonic power, 50 °C ultrasonic temperature, and 20 U mL⁻¹ bromelain. © 2024 Society of Chemical Industry.

The review comprehensively examines the intricate regulation of iron uptake and metabolism in the human body, shedding light on the essential role of various transporters and hormones in maintaining human health.