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为了阐明不同保藏温度对淡水鱼类鲜度变化的影响,采用K值、TVB-N、细菌总数和感官检定等 4种鲜度指标,对鳙在 20℃～-3℃范围的 5种不同温度贮藏中的鲜度变化进行比较系统的测定和考察。结果表明:(1)鳙的鲜度变化。在20℃和10℃常温下速度很快,保鲜期从数小时到4天;在 0℃前后的3种低温下速度变慢,保鲜期最长的可达 11天。(2)4种鲜度指标中,以感官的一、二、三级为基准,K 值的一、二级鲜度大体高于或等于感官的一、二级;而 TVB-N 一、二级鲜度(也包括细菌总数)则大体相当于或低于感官二、三级,显示了K值作为代表鱼体死后早期高鲜度等级的特征。(3)计算K 值变化速度常数 k_f 值表明 20℃的 K值变化速度较 10℃高6.3倍,而10℃较0℃仅高3.9倍,显示保持接近 0℃的低温,能明显抑制K值的变化,保持较好的鲜度。文中并指出了在5℃以下的低温范围,由于TVB-N 的数量水平偏低,似不适于作为鳙一类淡水鱼鳞度指标,认为在我国采用 K 值鲜度指标更适合淡水鱼高鲜度质量标准的要求。
In order to clarify the influence of different storage temperature on the freshness of freshwater fish, four freshness indexes, K value, TVB-N, total bacteria and sensory test, were used to test the freshness of freshwater fish at five different temperatures ranging from 20 ℃ to -3 ℃ Changes in the freshness of the storage system to conduct a more systematic determination and inspection. The results showed that: (1) 鲜 freshness changes. At 20 ℃ and 10 ℃ under normal temperature fast, fresh from a few hours to 4 days; 0 ℃ before and after the 3 kinds of low temperature slow down, the longest shelf life of up to 11 days. (2) Among the four freshness indexes, the first and second grades freshness of K value are generally higher than or equal to the first and second grades of the senses on the basis of the first, second and third grades of the sensory organs; while TVB-N, The grade freshness (also including the total number of bacteria) is then roughly equal to or lower than the sensory level two or three, indicating the K value as a characteristic of the early high freshness rating of the fish after death. (3) Calculating the k-value of the change rate constant k_f value shows that the change rate of K value at 20 ℃ is 6.3 times higher than that of 10 ℃, while that of 10 ℃ is only 3.9 times higher than that of 0 ℃. Change, maintain a good freshness. In the paper, it is pointed out that because of the low level of TVB-N in the low temperature range below 5 ℃, it is not suitable for the scale index of freshwater fish. It is considered that the freshness index of freshwater fish is more suitable for freshwater fish Quality standards requirements.