Document Type : Research Paper
Authors
1
Department of Food Science and Technology, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
2
Department of Fisheries, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
Abstract
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 functions 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 ºC. 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 (p<0.05). 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 0 to 7 kGy reduced the TVB-N content (p< 0.05). According to the results obtained from comparing colorimetric parameters, increasing radiation dose did have an influence on L*, a* and b* indices of shrimp samples. Furthermore, increasing the storage time reduced L* and b* index while increased a* (p<0.05). 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.
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