Quality deterioration of lipids and muscle of gamma irradiated tilapia fish fillets during storage in ice

Full text: Food irradiation is a method of meat, poultry and fish preservation has a potential to improve its quality and extend the shelf life. Therefore the present study was carried out to identify quality deterioration of gamma irradiated tilapia fish fillets. Two different doses of gamma irradiation (1 kGy and 3 kGy) were applied while preserving at 0 ± 1 °C. The quality changes were observed for 77 days storage period at 7 days' time intervals by measuring Peroxide value (PV), Thiobarbituric acid value (TBA), Free fatty acid value (FFA) and Total bacterial count (TPC). PV was maximize at 28 days in non-irradiated and 3 kGy irradiated tilapia and at 14 days in 1 kGy irradiated fillets. TBA value showed highest at 21, 28 and 35 days in non-irradiated, 1 kGy and 3 kGy irradiated fillets respectively (0.014, 0.038 and 0.012 mg MDA/meat kg). At 56 days non-irradiated tilapia showed maximum FFA value (20.735%) while 27.829% FFA at 77 days and 23.992% at 70 days in 1 kGy and 3 kGy irradiated fillets respectively. The TPC was increased with the progress of storage period. Within 7 days non-irradiated fillets exceeded unaccepted level (2.82 x 10⁶ cfu g^-1), 1 kGy irradiated fillets took 56 days (1.08 x 10⁶ cfug^-1) and 3 kGy irradiated tilapia exceeded level at 70 days (1.21 x 10⁶ cfu g^-1) in TPC. The results revealed that gamma irradiation increase the microbial quality while degrade the lipid deterioration of the tilapia fillets. (author)