Objective To investigate the effects of repeated freeze-thaw cycles, induced by temperature fluctuations during cold chain circulation, on the quality deterioration of pre-prepared grilled fish. Methods An accelerated deterioration model was established through extreme treatment to examine the effects of up to 8 freeze-thaw cycles on microstructure, texture properties, pH, color parameters and lipid oxidation. Correlation analysis was conducted to identify the primary factors contributing to quality degradation. Results As the number of freeze-thaw cycles increased, muscle tissue damage intensified, myofibril structures fractured, and hardness, elasticity, chewiness and shear force declined, while adhesiveness increased. The pH value showed a decreasing-then-increasing trend. Overall, the lightness value (L*) progressively decreased, while the redness (a*) and yellowness (b*) values continuously increased. The thiobarbituric acid reactive substances (TBARS) value significantly increased from 0.28 mg/kg to 2.00 mg/kg (P<0.05). After 6 cycles, the total volatile basic nitrogen (TVB-N) content exceeded the national safety limit for consumption (27.43 mg/100 g, national standard limit≤25 mg/100 g). Conclusion The quality of pre-cooked grilled fish significantly deteriorates during distribution, and the damage becomes more severe with increasing freeze-thaw cycles. After more than 5 cycles, the product is no longer suitable for consumption. These findings provide a scientific basis for quality control strategies in the cold chain logistics of pre-prepared aquatic products.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |