Effect of gamma irradiation and modified atmosphere packaging on the shelf-life of white shrimp (Metapenaeus affinis)

This study attempts to investigate the variations in pH, thiobarbituric acid (TBA), total volatile basic nitrogen (TVBN), free fatty acids (FFA), colorimetric parameters (L*, a*, b*), total viable bacterial count (TVC) and textural profile analysis as a function of storage time to evaluate the effect of gamma irradiation (0, 1, 3, 5, 7 kGy) and modified atmosphere packaging (MAP) on the shelf life of white shrimp (Metapenaeus affinis) stored for 15 days at 4 ordm;C. Compared to the control group, increasing radiation dose (up to 7 kGy) and storage time (up to 15 days) led to an increase in pH index (P 0.05). TBA, FFA and TVC increased with higher radiation dose and storage time. Prolong the storage time, increased the TVBN to the end of the fifteenth day, while higher gamma doses from 0 to 7 kGy reduced the TVBN content (P 0.05). According to the results obtained from comparing colorimetric parameter, increasing radiation dose did have an influence on L*, a* and b* indices of shrimp samples. Furthermore, increasing the storage time (P 0.05) reduced L* and b* index while increased a*. Increasing the gamma radiation and storage time reduced the hardness and chewiness treated shrimp samples (P 0.05). Based on the microbiological and chemical results, the optimal storage time for shrimp under various radiation doses was measured in 7 kGy treatment and on day 12. This treatment could improve the storage time by 6 days compared to the control treatment.