Keeping quality of bolti (Tilapia nilotica) and bayad (Bagrus bayad) fish fillets as affected by some pretreatments before frozen storage for six months

摘要

In this study, different pretreatments were applied to bolti (Tilapia nilotica) [Oreochromis niloticus] and bayad (Bagrus bayad) fish fillets before frozen storage for 6 months: treatment with sodium tripolyphosphate, treatment with sodium tripolyphosphate and coating with sodium alginate, glazing, and dipping in distilled water (control). Analyses for moisture and lipid contents, pH, thiobarbituric acid (TBA), free fatty acid (FFA), water holding capacity (WHC) and plasticity, cooking loss, thawing loss, and microbial load; separation and identification of lipids and phospholipids were carried out at zero time and during frozen storage at 2 months intervals. Sensory evaluation using the ranking method and critical differences was carried out by the end of the storage period. Results indicate that treatment of bolti fish fillets with sodium tripolyphosphate and coating with a film of sodium alginate might be an excellent and unique pretreatment for optimizing the keeping quality of fish fillets during frozen storage. Bayad fish fillets showed lower acceptability after 6 months storage compared with bolti fish fillets.