模拟冷链流通中温度波动对养殖金鲳鱼鱼肉品质及微生物多样性的影响

为研究温度波动对冷鲜养殖金鲳鱼鲜度品质的影响,通过模拟冷链流通的温度条件,分析样品流通过程中菌落总数、嗜冷菌数、pH值、挥发性盐基氮值、硫代巴比妥酸值及K值的变化趋势,并采用高通量测序技术研究了流通过程中微生物群落演替规律。结果表明:随着流通时间的延长,鱼肉中的菌落总数和嗜冷菌数呈上升趋势,鲜度指标呈劣变趋势,其中断链组的品质劣变速度显著高于冷链组(P<0.05),鲜度指标与微生物指标之间具有显著相关性(P<0.05),能较好反映冷鲜金鲳鱼在流通过程中的鲜度损失情况。Alpha多样性指数和主成分分析表明,金鲳鱼中的微生物群落多样性与结构受环境温度波动的影响。样品流通过程中的菌相分析表明:在门水平上主要优势菌以变形菌门和厚壁菌门为主,在属水平上以苯基杆菌属为主,其中冷链组的次要优势菌是鞘氨醇单胞菌属、长绳菌属和unclassified_Anaerolineaceae；断链组的次要腐败菌是八叠球菌属、长绳菌属和unclassified_Anaerolineaceae。同时,从微生物代谢水平上发现,冷藏过程中断链组参与新陈代谢的相关基因相对丰度高于同一时间的冷链组。研究结果反映了冷链流通过程中金鲳鱼因温度波动产生潜在的质量安全风险,同时希望为从微生物层面开发针对性的金鲳鱼保鲜技术和冷链物流建设提供参考。

Effect of Temperature Fluctuation During Simulated Cold Chain Circulation on Meat Quality and Microbial Diversity of Cultured Trachinotus ovatus

To study the effects of temperature fluctuation on the freshness and quality of cold fresh cultured Trachinotus ovatus, the temperature conditions during cold chain circulation were simulated, and the variation trends of total number of colonies and cryophilic bacteria, pH value, TVB-N value, TBA value, and K value during sample circulation were analyzed, and the microbial community succession was tested by high-throughput sequencing technology. The results showed that with the extension of circulation time, the total number of colonies and cryophilic bacteria in fish meat increased, accompanied by the deterioration of freshness indexes, in which the quality deterioration rate of breaking chain group was significantly higher than that of cold chain group (P<0.05). There was a significant correlation between microbial indexes and freshness indexes (P<0.05), which could well reflect the freshness loss of cold fresh Trachinotus ovatus during the circulation process. Alpha diversity index and principal component analysis showed that the diversity and structure of microbial community in Trachinotus ovatus were affected by the fluctuation of ambient temperature. The analysis of the bacterial phase during the circulation of the samples showed that the main dominant bacteria at phylum level were Proteobacteria and Firmicutes. At genus level, Phenylobacterium was the main dominant bacteria. The secondary dominant bacteria in the cold chain group were Sphingomonas, Longilinea and unclassified_Anaerolineaceae. The secondary dominant bacteria in breaking chain group were Sporosarcina, Longilinea and unclassified_Anaerolineaceae. From the microbial metabolism perspective, it was found that the relative abundance of genes involved in metabolism in breaking chain group during refrigeration was higher than that in the cold chain group at the same time. The research results reflected the potential quality and safety risks of Trachinotus ovatus due to temperature fluctuation during cold chain circulation. At the same time, it was hoped to provide a reference for the development of targeted Trachinotus ovatus preservation technology and the construction of cold chain logistics from the microbial perspective.