Effect of different thawing methods on the physicochemical, microbial parameters and sensory analysis of frozen Euthnnus affinis

This study was to evaluate the effect of different thawing methods (Immersion, Ambient air, Refrigerator and Microwave) on the quality of frozen Euthnnus affinis. Fresh fish after packaging frozen in tunnel freezing (-36 °C) and stored in -18°C for 2 months. Chemical, physical, microbiological parameters and sensory evaluation were investigated after thawing. Significant difference (p<0.05) was observed between the pH of control and other thawing treatments. The highest and lowest amount of TMA was obtained in refrigerator thawing (1.94±0.32) and control (1.12±0.03) treatments respectively. The lowest amount of TBA was observed in immersion thawing (1.56±0.10) and control (1.44±0.03) treatments. The highest amount of TVB-N (25.20±1.40) and lowest amount of WHC (76.77±5.82) were obtained in microwave thawing treatment. The lowest amount of thawing and cooking loss were observed in ambient air thawing (1.71±0.26) and control (11.44±0.06) treatments respectively. No significant difference (p>0.05) was observed between the PTC and TVC count of control and ambient air thawing treatment. The sensory analysis of ambient air thawing treatment was better than the other treatments. The results of this research showed the ambient air thawing is recommended to preservation of frozen Euthnnus affinis.