液氮冷冻处理对养殖大黄鱼保鲜品质及菌群结构的影响
Effect of Liquid Nitrogen Frozen Treatment on Fresh-keeping Quality and Colony Structure of Cultured Large Yellow Croaker
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摘要: 为研究液氮冷冻处理对养殖大黄鱼保鲜品质及菌群结构的影响,采用液氮浸渍冻结处理养殖大黄鱼,以TBA、TMA、TVB-N、K值以及菌落总数为指标,未处理样品作为空白对照,分析样品在低温贮藏条件下鲜度品质变化情况,并通过高通量测序技术研究液氮冷冻处理对养殖大黄鱼菌群结构的影响。结果表明:在储藏过程中,液氮组和空白组的各项指标都随时间的延长呈上升趋势,到保藏第14 d时,液氮组样品的TBA值为(1.71±0.08)mg/100 g,空白组样品的TBA值为(2.10±0.43)mg/100 g。第14 d时液氮组和空白组的TMA分别为(5.46±0.037)mg/100 g和(6.99±0.008)mg/100 g。空白组在储藏第2 d时,TVB-N值已达到(14.7±0.16)mg/100 g,而液氮组在储藏第4 d时,TVB-N值为(15.6±0.34)mg/100 g。第14 d时液氮组和空白组的K值分别为45.1%和55.6%。液氮组与空白组相比,经液氮处理后的样品,菌落总数下降了98.21%,说明液氮冷冻具有较好的抑菌作用。菌群结构结果表明液氮冷冻处理对养殖大黄鱼贮藏期菌群结构有一定影响。液氮组各项指标变化速率除菌落总数,均低于空白组。说明液氮冷冻处理能够延迟养殖大黄鱼腐败变质的进程,让养殖大黄鱼能够保存更长的时间。Abstract: To study the effect of liquid nitrogen frozen treatment on fresh-keeping quality and colony structure of cultured large yellow croaker,large yellow croaker were managed by liquid nitrogen freezing treatment,the TBA,TMA,TVB-N,K and the total number of colonies were taken as indexes. The untreated samples were used as blank control,analyze the freshness quality of samples under low temperature storage conditions. The effect of liquid nitrogen freezing on the colony structure of cultured large yellow croaker was studied by high throughput sequencing. The results showed that the indexes of liquid nitrogen group and blank group increased with the time of storage,and the TBA value of liquid nitrogen group was(1.71±0.08) mg/100 g on the 14th day after storage,the TBA of the blank group was(2.10±0.43) mg/100 g. At the 14th day,the TMA of the liquid nitrogen group and the blank group were(5.46±0.037) mg/100 g and(6.99±0.008) mg/100 g,respectively. In the blank group,the TVB-N value reached(14.7±0.16) mg/100 g on the second day of storage,while the TVB-N value reached(15.6±0.34) mg/100 g on the fourth day of storage. At the 14th day the K values of the liquid nitrogen group and the blank group were 45.1% and 55.6%,respectively. Compared with the blank group,the total number of colonies decreased by 98.21% after liquid nitrogen treatment,indicating that liquid nitrogen freezing had better bacteriostasis. The results showed that liquid nitrogen freezing treatment had some influence on the colony structure of cultured large yellow croaker. The total change rate of the indexes in the liquid nitrogen group was lower than that in the blank group. Indicating that liquid nitrogen freezing treatment could delay the process of corruption of large yellow croaker,allow large yellow croakers to be kept for longer.