Effect of electron beam irradiation on the biochemical, microbiological and sensory quality of Litopenaeus vannamei during chilled storage

The effects of electron beam irradiation (0, 2.5, 5.0, 7.5 and 10 kGy) on the quality characteristics of vacuum packed headless vannamei stored under chilled condition (2 degrees C) was assessed. The total volatile base nitrogen, non protein nitrogen content, peroxide value and thiobarbituric acid reactive substances showed an increasing trend during storage. Texture analysis indicated that shrimp irradiated at above 2.5 kGy dose had a lower hardness than control. L* value showed a decreased trend during storage (51.87-13.89). Moreover, b* and a* value showed a gradual increase during storage. The total viable count was lower in the irradiated sample than control. A similar trend also observed for psychrophilic, pseudomonas and H2S former count. There is a significant (p < 0.05) reduction in Brochothrix thermosphacta and lactobacillus count in the irradiated sample. Based on the microbial and sensory analysis control had a shelf life up to 12th day. However, electron beam irradiated sample had extended shelf life of 15-23 days with respect to dose level.