ANTIOXIDANT EFFECT OF ROSEMARY EXTRACT AND α-TOCOPHEROL ON THE QUALITY OF COATED FRIED NILE TILAPIA FILLETS (Oreochromis niloticus) DURING CHILLING
AND FROZEN STORAGE
Ibrahim F. Mohamed
Central Laboratory for Aquaculture Research, Abbassa, Agriculture Research Center, Ministry of Agriculture, Egypt.
This study was carried out to investigate the effect of Rosemary extract (R.E.) and α-tocopherol on the quality of coated fried Nile tilapia fillets (Oreochromis niloticus) during chilling and frozen storage. Nile tilapia fillets were treated with (R.E.) 0.1%, 0.2%, 0.3% and α-tocopherol 0.1% then stored for 5,10 and 15 days at 4±1°C and for three months at -18±2°C. Then chemical tests including Peroxide value (PV), Thio-barbituric acid (TBA), Tri-methylamine-nitrogen (TMA-N) and Total volatile base-nitrogen (TVB-N) were done to evaluate the preservative effect of (R.E.) and α-tocopherol during storage. The PV and TBA increased in all treatments due to lipid oxidation. Results showed that TMA-N,TVB-N, value of (R.E.) and α-tocopherol treated samples were significantly lower than those of the control samples (P<0.05). Results of our investigation revealed that R.E. retarded oxidative changes in chilling and frozen coated fried Nile tilapia fillets whereas R.E. 0.1%, 0.2% and α-tocopherol 0.1% were not as effective as R.E. 0.3% on oxidative stability. Best oxidation inhabitation results on chilling and frozen coated fried Nile tilapia fillets was obtained when employing of R.E. The obtained results also showed that there was a significant (p<0.05) enhancement in sensory quality attributes of fried Nile tilapia fillets; samples treated with R.E. and α-tocopherol
Conclusion, The tested R.E. had a high effectiveness as antioxidative and antimicrobial should be utilized for extending the shelf-life through retarded the spoilage and enhancing quality attributes of coated fried Nile tilapia fillets during chilling and frozen storage.