南方大口鲶在微冻和冻藏条件下鲜度及品质的变化

为研究3种贮藏温度对南方鲶品质变化的影响,分别对微冻(-3℃)和冻藏(-18、-25℃)条件下南方大口鲶的菌落总数、pH、挥发性盐基氮(total volatile basic nitrogen,TVB-N)值、K值、色差值、弹性、硬度等指标的变化进行研究,并结合感官评价分析其新鲜度。结果表明:贮藏温度越低,各指标变化趋势越慢;随贮藏时间的延长,3种贮藏温度下南方大口鲶的感官评分、亮度值L*、弹性值及硬度值均不断降低,菌落总数、TVB-N、K值和黄蓝值b*均呈上升趋势,pH均呈先降低后增高的V型变化趋势。综合各指标的实验结果得到:南方鲶-3℃微冻贮藏下货架期为18 d;冻藏组在实验终点(60 d)并未出现腐败变质的情况;与微冻相比,冻藏能明显延长南方鲶的贮藏期。

Changes in the Quality and Freshness of Silurus meridionalis Chen under Partial Freezing and Frozen Conditions

In order to obatin the effects of three storage temperatures on the quality change of Silurus meridionalis Chen,the changes of total number of colonies,pH,total volatile basic nitrogen(TVB-N),K value,color value,elasticity and hardness of Silurus meridionalis Chen in partial freezing storage(-3℃)and frozen storage(-18,-25℃)were studied respectively. And combined with sensory evaluation,the freshness of Silurus meridionalis Chen was analyzed. The results showed that the changes rate of each index reduced with the decrease of the storage temperature. With the extension of the storage time,the sensory scores,brightness value L*,elasticity and hardness index decreased continuously under three kinds of storage temperature,and the total number of colonies,TVB-N,K value and yellow-blue value b* were on the rise,while the pH was firstly decreased and then increased which showed an V-type change. According to the experimental results of indicators,the shelf life of Silurus meridionalis Chen was 18 days at-3℃,while the frozen storage group did not show spoilage at the end of experiment(60 d). What's more,compared with the partial freezing storage,the frozen storage could significantly prolong the storage period of the Silurus meridionalis Chen.