Abstract: This study investigated the effects of temperature fluctuations on the quality deterioration of frozen salmon, aiming to provide theoretical guidance for the optimization of household refrigeration temperature control systems. Salmon samples were stored under constant temperature and fluctuating temperature conditions for 0—40 days, and changes in sensory quality, color parameters (L*, a*, b*), total volatile basic nitrogen (TVB-N), total viable counts (TVC), and texture properties were systematically evaluated. Results revealed that temperature fluctuations significantly accelerated quality degradation. After 40 days, sensory scores of the fluctuating group decreased to approximately 14, with markedly higher L*, a*, and b* values, indicating pronounced surface drying and browning. TVB-N and TVC increased to 1.3-fold and 1.32-fold those of the constant group, respectively, reflecting severe tissue damage and enhanced microbial activity. Hardness and chewiness decreased by 49.5% and 51.9%, significantly exceeding reductions observed in the constant group. Mechanistic analysis suggested that repeated freeze-thaw cycles induced by temperature fluctuations promoted ice crystal recrystallization, protein denaturation, and lipid oxidation, leading to structural destruction and flavor deterioration. These findings underscore the importance of stable low-temperature control in frozen storage and provide scientific support for advancements in refrigeration technologies and cold-chain management.

Key words: Frozen storage, Temperature fluctuation, Salmon, Quality deterioration, Ice crystal recrystallization, Refrigerator preservation technology