To enhance the value of tropical sea cucumbers and to address issues such as poor texture and nutrient loss resulting from traditional long-time thermal processing, this study investigated the effects of sequential high hydrostatic pressure (HHP) and boiling on the physicochemical properties, quality characteristics, and microstructure of tropical sea cucumbers. The results showed that with increasing boiling time, the mass loss rate and total sugar content of tropical sea cucumbers decreased, while the hardness and chewiness initially increased and then decreased. For the combination of HHP followed by boiling, as pressure increased, the chewiness and viscosity increased, while the hardness first increased and then decreased. Among all pressures tested, the sample treated with 100 MPa HHP followed by boiling had the lowest chewiness, viscosity, and hardness. For the combination of boiling followed by HHP, as pressure increased, the chewiness decreased, while the hardness and viscosity first increased and then decreased. The sample treated with 500 MPa HHP after boiling exhibited the lowest chewiness, viscosity, and hardness. Compared with tropical sea cucumbers boiled for 30 min, the water content of sea cucumbers subjected to HHP followed by boiling shifted from free water to immobile and bound water, whereas in the samples subjected to boiling followed by HHP, the proportions of immobile and bound water decreased, and the proportion of free water increased. The myofibrils of tropical sea cucumbers treated with HHP followed by boiling became more compact, with smaller pores, leading to better chewiness and protein stability. The different processing sequences significantly affected the textural properties of tropical sea cucumbers (P < 0.05). A comprehensive evaluation of nutritional and quality indices indicated that tropical sea cucumbers processed with HHP followed by boiling had superior nutritional and sensory qualities. The findings provide a reference for the processing of tropical sea cucumbers.

Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans. The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E. coli O157:H7 than using either alone. This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level. The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E. coli O157:H7 found that acid resistance systems in kojic acid were activated, and the cell membrane and genomic DNA were destructed in the cells, resulting in “oxygen starvation”. The oxidative stress response triggered by tea polyphenols inhibited both sulfur uptake and the synthesis of ATP, which affected the bacteria's life metabolic process. Interestingly, we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA, respiration, tricarboxylic acid cycle. The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E. coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.