Effects of refreezing on microbiological and physiochemical properties of Barramundi (lates calcarifer, bloch) fillets

Abstract

The aim of this study was to investigate the effects of different numbers of freeze–thaw cycles (0, 1, 2 and 3) on barramundi (Lates calcarifer) fillets. Quality and shelf life of fillets were evaluated using the microbiological and physiochemical analyses. The fillets were individually frozen on a polystyrene dish in an air blast freezer at -80C for 8 h, stored in a freezer at -20C for 20 days and then analysis was carried out on the 21st day from the beginning of frozen storage. The results obtained were compared with those of fresh fillets. This study revealed that the pH, total volatile base nitrogen, total viable counts, and L* and b* values of freeze-thawed fillets increased significantly (P < 0.05) with number of freezing cycles whereas ash, protein content and rheological parameters of fillets decreased significantly (P < 0.05) after three freeze–thaw cycles compared with fresh fillets.