冷藏大口黑鲈鱼片品质变化规律及优势腐败菌致腐能力分析

Analysis of quality changes rule of Micropterus salmoides during cold storage and spoilage ability of dominant spoilage bacteria

中文关键词:  大口黑鲈鱼  冷藏  品质  优势腐败菌  致腐能力

英文关键词:Micropterus salmoides  cold storage  quality change  dominant spoilage bacteria  spoilage ability

中文摘要:

      目的 分析冷藏大口黑鲈鱼片品质的变化规律并确定其贮藏过程中的优势腐败菌及其致腐能力。方法 以新鲜鲈鱼为原料, 通过测定鱼肉的质构特性、菌落总数、挥发性盐基氮(total volatile basic nitrogen, TVB-N)和K值等指标, 对冷藏过程中鱼片的品质和优势腐败菌及其致腐能力进行了分析, 并通过16S rRNA序列鉴定分析各腐败菌的种属。结果 质构特性、菌落总数、TVB-N、K值等品质相关指标的测定结果表明, 随着贮藏时间的延长, 鱼片的咀嚼性和胶着性均呈缓慢下降的趋势; 菌落总数逐渐增长; TVB-N在贮藏前7 d变化不大, 在第7 d后急速上升; K值在第7 d时超过了60%, 达到了初期腐败。采用选择性培养基获得鲈鱼腐败期的特定菌落, 结合菌落形态观察、16S rDNA与革兰氏染色技术, 确定所属菌株属种, 并评价各菌株的致腐能力。筛选出T2、C1和C2 3株菌为4℃贮藏鲈鱼片的疑似优势腐败菌。16S rDNA鉴定出这3株菌分别为希瓦氏菌、假单胞菌和普罗维登斯菌。根据接种这3株腐败菌的大口黑鲈鱼片的TVB-N产量因子(YTVB-N/CFU)的评价结果, 确定这3株腐败菌的致腐能力为假单胞菌>希瓦氏菌>普罗维登斯菌。结论 假单胞菌为4℃贮藏的鲈鱼片腐败的优势菌。

英文摘要:

      Objective To analyze the changes rule in quality of Micropterus salmoides during refrigeration, as well as the dominant spoilage bacteria and their ability to cause spoilage during cold storage. Methods The texture characteristics, total viable count, total volatile basic nitrogen (TVB-N) and K value of Micropterus salmoides were measured to evaluate the quality of Micropterus salmoides during refrigeration, as well as the dominant spoilage bacteria and their ability to cause spoilage were analyzed. The species of each spoilage bacteria were identified and analyzed through 16S rRNA sequence analysis. Results The results of quality related indicators such as texture characteristics, total number of bacterial colonies, TVB-N, and K value showed that the chewiness and adhesiveness of fish fillets declined slowly; the total number of bacterial colonies gradually increases; TVB-N rapidly increased after the 7th day; at the 7th day, the K value exceeded 60%, reaching the initial stage of corruption. The selective culture mediums were used to obtain specific colonies during the decay period of Micropterus salmoides. The genus and species of the strains were determined by colony morphology observation, 16S rDNA and Gram staining techniques. The 3 strains of T2, C1 and C2 were selected as suspected dominant spoilage bacteria for storing Micropterus salmoides slices at 4℃. The 3 strains were identified as Shewanella, Pseudomonas, and Providence using 16S rDNA. The spoilage ability of these 3 strains were evaluated by TVB-N yield factor (YTVB-N/CFU). The spoilage ability was Pseudomonas>Shewanella>Providence. Conclusion Pseudomonas is the dominant bacteria for the spoilage of Micropterus salmoides slices stored at 4℃.