Effect of Gamma Radiation in Combination with Low Temperature Refrigeration on the Chemical, Microbiological and Organoleptic Changes in Pampus chinensis (Euphrasen, 1788)

The present study was carried out to evaluate the efficiency of gamma radiation (3, 5 and 8 kGy) in combination with low temperature (-20°C) for extending the quality and shelf-life of degutted fresh Chinese pomfret, Pampus chinensis. Quality assessment was studied by monitoring the chemical (TVN, TMA), microbiological (TBC, TMC) and organoleptic changes in irradiated and non-irradiated (control) samples. Among chemical indicators of spoilage, total volatile nitrogen (TVN) values increased to 55 mg/100 g for nonirradiated samples whereas for irradiated fish lower values of 45 mg/100 g, 27.5 mg/100 g and 18.7 mg/100g were recorded at 3, 5 and 8 kGy respectively (day 90). Significantly lower values were obtained for irradiated samples reaching a final trimethylamine (TMA) value of 7.1, 5.3 and 4.9 mg N/100 g at 3, 5 and 8 kGy respectively whereas for non-irradiated samples it increased slowly attaining a value of 32.5 mg N/100 g after 90 days. Total bacterial counts as well as total mould counts for non-irradiated pomfret were higher than that of irradiated fish. The organoleptic scores of control sample were gradually decreased with the progress of storage period whereas irradiated samples showed the acceptable score upto 90 days. This study concludes that gamma radiation in combination with low temperature showed maximum shelf-life extension (90 days) in each dose of radiation used but in 8 kGy radiation, Pampus chinensis showed best quality.