Abstract

The quality of Nile tilapia (Oreochromis niloticus) produced in Algeria was assessed after refrigerated (4°C) storage as well as ambient temperature (30°C) keeping, corresponding to usual fish selling conditions in Algeria. Sensorial, microbial and biochemical analyzes were conducted in parallel. Moreover, the nutritional quality of fresh tilapia was also assessed by determining the proximate composition and the fatty acids profile. Results of lipid oxidation, namely hydroperoxydes and thiobarbituric acid-reactive substances (TBARS), proteolysis, represented by total volatile basic nitrogen (TVB-N) and trimethylamine (TMA-N), sensory assessment and bacterial load were highly correlated. They demonstrated that the shelf life of tilapia is limited to 12 h and five days of storage at 30 and 4°C respectively. After these period of time, fish was rejected by sensorial analysis and all the parameters thresholds (fixed in the present study at 0.85 mg MDA kg^-1 of wet weight for TBARS, 35 mg TVB-N 100 g^-1 of flesh, 8 mg TMA-N 100 g^-1 of flesh and 6 log cfu g^-1 for total viable count) were exceeded.

Key words: Shelf life, Oreochromis niloticus, fatty acid profile, thiobarbituric acid-reactive substances (TBARS), trimethylamine (TMA), hydroperoxides.