Extending shelf life and keeping protein nutritional value of drunk Bullacta exarata by suitable electron beam irradiation

Abstract: Bullacta exarata is a kind of small economic shellfish distributed in intertidal zone of China's coastal. In the southeast coast of China, B. exarata is often made to drunk products and eaten raw, hence it may pose health hazards to consumers when contaminated with microorganisms. As limited alternative methods are available to sterilize the drunk B. exarata while preserving its raw characteristics, electron beam irradiation may be considered as an effective method for sterilization.This study sought to explore the bactericidal effect and changes of sensory quality and protein nutritional value of drunk B.exarata treated by electron beam irradiation and provide an experimental basis for application of irradiation sterilization technology in drunk B. exarata. Using drunk B. exarata as research material, the influence of electron beam irradiation on total plate count, sensory score, protein content, and amino acids composition were investigated, and then the shelf life of drunk B. exarata under refrigerated or room temperature were determined.The results were summarized as follows: 1) 1-9 kGy dose of electron beam irradiation did not cause the change of color or shape of B. exarata, but they were off-flavor after irradiation with a dose of 7 or 9 kGy. 2) The higher the irradiation dose, the better the antiseptic effect. The D10 value was 3.46 kGy when the total plate count of B. exarata was 1 200 cfu/g before irradiation. The sterilization effect with a 3 or 5 kGy dose was obvious, and total plate count of drunk B. exarata were less than 5 000 cfu/g both refrigerated and with room temperature storage within 360 days. 3) There was no significant effect of electron beam irradiation on protein content, and the limiting amino acid was not changed after irradiation. However, the total content of amino acids, total content of essential amino acids, and scores of essential amino acids (AAS) in irradiated drunk B.exarata ascended. 4) According to the research about the sterilization effect and sensory score of drunk B. exarata, the recommended dose of electron beam irradiation was 3 kGy.The shelf life of drunk B. exarata treated by 3kGy irradiation was extended from 5 months to 12 months, and from less than 1 month to 3 months, respectively during cold and room temperature storage. This work can provide technical references for preservation of drunk B.exarata by electron beam irradiation.