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.