Evaluation of Effects of Three Drying Methods on the Quality of Oysters Based on Variation Coefficient Weight Method

Three dried methods including blast drying, vacuum drying and vacuum freeze drying were used to dry fresh oysters, and the nutrient compositions, color, rehydration rate, texture, production cycle, drying energy consumption and sensory score were subsequently determined. Furthermore, the coefficient of variation weight method was employed to calculate comprehensive scores for determining the optimum drying method of oysters. The results indicated that although its production cycle was the longest and energy consumption was highest, vacuum freeze drying was able to better preserve the various nutrients and reduce color difference of oysters, making their rehydration rate and texture characteristics (hardness, chewability and adhesive) significantly better than those dried by blast drying and vacuum drying (p<0.05). Moreover, the oysters dried by vacuum were rich in flavor, the highest sensory scores with the full body shiny obtained and the texture was suitable. Analysed by coefficient of variation weight method, L^*, hardness, chewability, adhesive and drying energy consumption contributed greatly to the comprehensive score of dried oysters, showing 0.105、0.112、0.121、0.109 and 0.120 respectively. The comprehensive score of drying methods was declining in the following order:Vacuum freeze-drying (0.780) > vacuum drying (-0.074) > blast drying (-0.707), the quality of oyster dried by vacuum freeze-drying was the best. The variation coefficient weight method, therefore, was feasible for the quality evaluation of dried oysters, which provided theoretical reference for its application in aquatic product processing technology optimization.