Abstract: In order to study the correlation between energy metabolism and processing quality of channel catfish with different prechilling durations, changes in energy reserves (including glycogen, lactic acid, adenosine-5’-triphosphate (ATP), and ATP-related compounds), metabolic enzyme activities (hexokinase (HK), pyruvate kinase (PK), lactate dehydrogenase (LDH), creatine kinase (CK)), and quality indicators (pH value, cooking loss rate, expressible moisture rate, texture characteristics, K value, and color) were evaluated during prechilling for 48 h at 4 ℃ after slaughter. The results showed that the contents of glycogen and lactic acid decreased continuously with increasing prechilling time up to 24 h, and then began to accumulate; the contents of adenosine-5’-diphosphate (ADP), adenosine-5’-monophosphate (AMP) and inosine-5’-monophosphate (IMP) decreased gradually, the content of hypoxanthine (Hx) and inosine (HxR) increased gradually, and ATP was almost undetectable; HK activity continued to decline, PK activity rose to the maximum after 8 h prechilling and then decreased, LDH and CK activity showed a volatile decline; pH and shear force gradually decreased; expressible moisture rate, cooking loss and whiteness remained stable within 24 h, and increased significantly after 48 h (P < 0.05), indicating that water-holding capacity decreased; K value continued to rise and remained within the high freshness range below 20% within 24 h. Correlation analysis showed that there was a significant positive correlation between glycogen and lactic acid contents (P < 0.05); K value was significantly negatively correlated with HK (P < 0.05), but significantly positively correlated with whiteness (P < 0.01); LDH was significantly positively correlated with CK and shear force, but significantly negatively correlated with whiteness (P < 0.05). Expressible moisture rate was significantly positively correlated with cooking loss rate (P < 0.05). Postmortem channel catfish within 24 h of prechilling is more conducive to quality control during processing.

Key words: channel catfish, prechilling time, energy change, metabolic enzyme activity, processing quality