Effects of freeze-thaw cycles on quality of silver carp (Hypophthalmichthys molitrix) fillets

This study was conducted to evaluate the effects of freeze-thaw cycles on some quality parameters of silver carp fillets. The prepared fillets were packaged in zip lock bags and were subjected to 0, 1, 2, 3, 4 and 5 freeze-thaw cycles, respectively. Heme iron content decreased, and dry matter increased as the number of freeze-thaw cycles increased (P<0.05). In the fillets that were thawed 1, 2 and 5 times, free drip loss on cooking were significantly (P<0.05) more than fresh fillets. The highest water holding capacity observed in the highest pH value. L*, a*, b* and total color difference values (from the fresh sample) (∆E) increase with increasing freeze-thaw cycles. Folding test showed that, gel forming ability of silver carp fillets decreased with increasing freeze-thaw cycles. The results revealed that multiple freeze-thaw have undesirable effects on physical and chemical quality of fillets, therefore re-freezing of thawed fillets is not recommend.