Research Article: 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 (TVB-N), 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 (۰, ۱, ۳, ۵, ۷ kGy) and modified atmosphere packaging (MAP) on the shelf life of white shrimp (Metapenaeus affinis) stored for ۱۵ days at ۴ ºC. Compared to the control group, increasing radiation dose (up to ۷ kGy) and storage time (up to ۱۵ days) led to an increase in pH index (P< ۰.۰۵). TBA, FFA and TVC increased with higher radiation dose and storage time. Prolong the storage time, increased the TVB-N to the end of the fifteenth day, while higher gamma doses from ۰ to ۷ kGy reduced the TVB-N content (P< ۰.۰۵). 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< ۰.۰۵) reduced L* and b* index while increased a*. Increasing the gamma radiation and storage time reduced the hardness and chewiness treated shrimp samples (P< ۰.۰۵). Based on the microbiological and chemical results, the optimal storage time for shrimp under various radiation doses was measured in ۷ kGy treatment and on day ۱۲. This treatment could improve the storage time by ۶ days compared to the control treatment.

Keywords:

Gamma irradiation , Shelf-life , Modified atmosphere packaging , Metapenaeus affinis