This study simulated 12-hour transportation stress in mirror carp (Cyprinus carpio). Muscle samples from both the control and stressed groups were stored at 4 ℃ for 0, 1, 3, and 5 days. After steaming, the samples were analyzed using gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), and other techniques to investigate changes in flavor compounds and sensory attributes, aiming to elucidate the effect of transportation stress on the flavor quality of refrigerated mirror carp. The results showed that transportation stress significantly altered the composition of flavor compounds during refrigeration. Specifically, the levels of bitter amino acids, total free amino acids, total volatile compounds, and hexanal increased, whereas those of umami amino acids(glutamic acid) and organic acids (malic acid and lactic acid) decreased in the stressed group. Moreover, the content of the umami compound inosine monophosphate (IMP) significantly decreased from days 1 to 3 of refrigeration after stress, while that of the bitter compound hypoxanthine (Hx) significantly increased from days 1 to 5. Sensory evaluation scores for taste, odor, and overall acceptability were lower in the stressed group than in the control group and declined with prolonged storage. In summary, refrigeration led to flavor deterioration of mirror carp, and transportation stress exacerbated this process, characterized by an accelerated loss of umami compounds (glutamic acid and IMP) and an increase in bitter and undesirable volatile compounds, thereby significantly reducing the sensory acceptability of fish meat.

The changes in the muscle quality of Wuchang bream during live transportation (3, 6, 12 and 24 h) were measured by ultra-high performance liquid chromatography, a color difference meter and an ultraviolet spectrophotometer. The results showed that after 3 h of transportation, the pH value, water-holding capacity, whiteness, brightness (L*), redness (a*), and the contents of lactic acid, muscle glycogen, ATP and its derivatives in fish muscle were 6.57, 70.33%, 52.22, 52.27, 0.29, 4.50 mg/g, 1.46 mg/g and 909.25 mg/100 g, respectively. With increasing transportation time to 24 h, the pH value first increased and then decreased to 6.33 (P < 0.05), while the lactic acid content initially decreased and then increased to 3.81 mg/g (P < 0.05). The water-holding capacity gradually increased to 76.05% and then decreased to 73.33%. The whiteness and L* gradually decreased to 47.64 and 47.71, respectively, whereas a* increased to 1.31 (P < 0.05). The content of muscle glycogen gradually decreased to 1.25 mg/g. The total content of ATP and its derivatives increased to 1116.62 mg/100 g; the ATP content decreased to 62.43 mg/100 g, while the content of the umami substance IMP increased to 747.91 mg/100 g, and the contents of the bitter substances inosine (HxR) and hypoxanthine (Hx) increased to 156.12 and 63.28 mg/100 g, respectively. It was concluded that the muscle quality of Wuchang bream changed significantly during live transportation under the influence of stress.