解冻方式对近江牡蛎肉感官特征和理化指标的影响

为获得冻结牡蛎肉的最佳解冻方式,以解冻时间、感官评分、质构、色差、解冻损失率、蒸煮损失率、pH、挥发性盐基氮(Total volatile basic nitrogen,TVB-N)、硫代巴比妥酸(Thibabituric acid,TBA)和菌落总数为指标,研究自然解冻、静水解冻、冷藏解冻、超声波解冻和微波解冻5种解冻方式对近江牡蛎感官特征和理化指标的影响,并采用变异系数权重法对解冻后牡蛎肉品质进行综合评价。结果表明:自然解冻(128 min)与冷藏解冻(309 min)所需时间较长,解冻后牡蛎肉的感官评分最小,分别为4.6、4.4分;TVB-N、TBA和菌落总数较大。微波解冻(1.5 min)和超声波解冻(9 min)耗时较短,感官评分较高,分别为6.12、6.0分;TVB-N、TBA和菌落总数最小,但蒸煮损失率和解冻损失率较大。静水解冻所需时间31 min,感官评分(6.0分)较高,但TVB-N、TBA和细菌总数较大。综合评价结果显示,解冻时间(权重值为0.357)对牡蛎肉品质影响最大,微波解冻综合评分(0.548)最高,是理想的近江牡蛎肉解冻方式,但持水力较低,微波解冻条件仍需进一步研究。

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.