The Effects of Two Forms of Ice on Microbiological and Physiochemical Properties of Barramundi (Lates calcarifer, Bloch) Fillets

Barramundi (Lates calcarifer) fillets were subjected to two different ice forms (prefreezing treatments: slurry ice [SI] and flake ice [FI]) for 0 (before freezing) and 1h and 1, 2, 4, 8 and 16 days prior to blast freezing at -80C for 8 h. Fillets were then stored in a freezer at -20C for 20 days.Microbiological and physiochemical analysis were then carried out. Fillets that were exposed to pre-freezing treatments in FI demonstrated larger increase in total volatile base nitrogen, total viable count and pH; larger decrease in protein content; and smaller increase in moisture content compared with SI at the end of the frozen storage. Fillets exposed to pre-freezing treatments in FI are significantly (P < 0.05) lighter (L*), more red (a*) and more yellow (b*) than those in SI. All textural parameters fell significantly as storage time progressed in both FI and SI, with hardness falling to a greater extent in FI than SI