Effects of frozen storage on texture, chemical quality indices and sensory properties of crisp Nile tilapia fillets

Abstract

Crisp Nile tilapia (Oreochromis niloticus) is a kind of valuable fish product with high muscle firmness and crispiness texture. However, with the change of physicochemical in crisp Nile tilapia, the frozen storage parameters and quality would be different comparing to normal Nile tilapia. Thus, the aim of this study was to analyze the changes in texture, chemical quality indices and volatile compounds of Nile tilapia fillets during frozen storage. The remaining storage time of the crisp Nile tilapia fillets could be estimated within 120 days. During frozen storage, fillets resulted in softer started at 90-day, and 36.75%, 45.74%, 48.81% and 20.37% reduction of hardness, springiness, gumminess and chewiness were observed at 120-day. Thiobarbituric acid reactive substances (TBARS) for frozen samples showed similar with fresh fillets within 60 days, while the TBARS was 1.97 folds higher than fresh one at 120-day. Low-field nuclear magnetic resonance (LF-NMR) indicated that the water loss of Nile tilapia fillets was significant changed at 120-day, which reduced more than 12.5% water out of weight. The volatile compound analysis showed that more free fatty acid will be detected at 120-day comparing to the fresh fillets. The combined results demonstrated that the crisp Nile tilapia fillets had the best quality before 60 days frozen storage then loss of some quality properties in longer freezing. Thus, these results identified the ideal storage strategy for the preservation of crisp Nile tilapia without affecting sensory appeal and commercial value.