Effect of Cold-Induced on Quality of Black Carp Fillet Stored at Controlled Freezing-Point

Abstract

Taken black carp fillet as the experimental material, effects of cold-induced on the quality of black carp fillets were studied. Three kinds of cold-induced modes were conducted in this experiment: 10°C constant temperature induction ( mode I ); 2°C/2h ( mode II ); 1°C/1h ( mode III ), at the same time did a comparison with controlled freezing-point storage ( mode IV ). The effect of cold-induced on pH, liquid loss, K value, activity of cathepsin B, free amino acid and proteolysis were compared. Results showed that: the pH value in fillets declined mildly at the storage, the drip loss value and K-value of fillets increased gradually as storage time increased. The K-value of fillets stored at mode I and II increased sharply, while relatively little change was observed in mode III and IV. Cathepsin B activities increased little bit at the storage. The cathepsin B activities of mode III was highest at 11.302U•g-1, when fillets were stored at controlled freezing-point (44h). Mode II was the second at 10.522 U•g-1. The total free amino acids (FAAs) of all modes increased to some extent. At 44 hours, the increment of total FAAs in mode II and III were 20.19% and 19.49%, which were superior to mode I (12.27%) and IV (12.97%). No significant differences in protein degradation were observed among those cold-induced modes, but it showed proteolysis on the SDS-PAGE.