Effects of Thawing Methods on Sensory Characteristics and Physicochemical Indices of Oyster(Ostrea rivularis Gould)Meat

In order to obtain the best thawing method for frozen oyster meat,the effects of natural thawing,static water thawing,refrigeration at 4℃ for thawing(denoted as refrigerated thawing),ultrasonic thawing and microwave thawing on the sensory characteristics and physicochemical properties of oyster were studied by means of thawing time,sensory scores,texture,color difference,thawing loss rate,cooking loss rate,pH,total volatile basic nitrogen(TVB-N),thibabituric acid(TBA)and total bacterial count. The weight method of coefficient of variation was used to evaluate comprehensively the quality of thawed oyster meat. The results showed that the oyster meat by natural thawing(128 min)and refrigerated thawing(309 min)both took a long time,leading to the lowest sensory scores(4.6 and 4.4 scores,respectively),with high TVB-N and total bacterial count of oyster meat. Nevertheless,the oyster meat treated by microwave thawing(1.5 min)and ultrasonic thawing(9 min)had shorter time and higher sensory scores(6.12 and 6.0 scores,respectively),with the lowest TVB-N,TBA and total bacterial count,but exhibited higher cooking loss rate and thawing loss rate. The static water thawing of oyster meat needed 31 min,and the final products showed a higher sensory score(6.0 scores),but their TVB-N,TBA and the total bacteria count were larger. The comprehensive evaluation results showed that the thawing time,whose weight value was 0.357,had the greatest impact on the quality of oyster meat,and the score of microwave thawing(0.548)was the highest. Therefore,microwave thawing was an ideal method for frozen oyster meat,but the thawed meat had low water holding capacity,whose conditions needed to further study.