咸干蓝点马鲛品质特征与优势菌群分析

Analysis of Quality Characteristics and Dominant Strains of Bacteria in Dried Salted Spanish Mackerel

中文关键词: 咸干鲅鱼  感官评价  品质特征  菌种鉴定

英文关键词: Dried salted fish  Sensory evaluation  Quality characteristics  Bacterial species identification

中文摘要:

      为了更好地了解传统咸干蓝点马鲛(Scomberomorus niphonius)(鲅鱼)的品质特征，以市售产品中感官品质较为突出的咸干鲅鱼作为研究对象，对其水分、含盐量、NaNO2含量、挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBARS)等理化指标进行了测定，并进一步对咸干鲅鱼中的优势菌进行了分离、纯化与鉴定。结果显示，咸干鲅鱼样品含水量为54.40%、含盐量为3.1%，属于半干低盐制品；NaNO2含量为5.07 mg/kg，符合相关食品安全标准的规定；TVB-N含量高达40.12 mg/100 g，说明发酵过程蛋白质降解程度较大；TBARS值为10.00 mg/kg，脂质氧化程度在感官可接受的范围内。咸干鲅鱼中的微生物以细菌为主，清酒乳杆菌(Lactobacillus sakei)、产气肠杆菌(Enterobacter aerogenes)、长赖氨酸芽孢杆菌(Lysinibacillus macrolides)和香坊肠杆菌(Enterobacter xiangfangensis)为优势菌。其中，清酒乳杆菌具有发酵菌的典型特征，可能在咸干鲅鱼发酵过程中起主要作用。

英文摘要:

      To better understand the quality characteristics of traditional dried salted Spanish mackerel, the dried salted Spanish mackerel product with the best organoleptic qualities among seven commercial products was chosen, and then its basic physical and chemical characteristics were analyzed, including its salt content, nitrite content, total volatile basic nitrogen (T-VBN) content, thiobarbituric acid reactive substances (TBARS) value, and so on. Furthermore, the dominant strains of bacteria, which have important impacts on the fermentation process and flavor formation, were isolated, purified, and identified from the dried salted Spanish mackerel product. The physiological and biochemical characteristics of these dominant bacterial strains were also studied in detail. The results showed that the water content of the traditional dried salted Spanish mackerel was 54.40%, and the salt content was 3.1%，which means that the analyzed product can be classified as a semi-dry and low-salt product. The nitrite content was 5.07 mg/kg, so the sample met relevant food safety standards. The TVB-N content of the dried salted fish product was 40.12 mg/100 g, which exceeds the TVB-N content limit of common fresh and frozen marine fish (30.00 mg/100 g), so these results indicated that the degree of protein degradation during fermentation was significant. The TBARS value was 10.00 mg/kg, which is slightly higher than the recommended standard (8.00 mg/kg); however, the degree of lipid oxidation in the sample was within the range of sensory acceptability because of its low moisture content. In addition, according to the results of plate counts of bacterial colonies, bacteria were inferred to be the dominant microorganisms in the traditional dried salted Spanish mackerel rather than yeasts or molds. On the basis of analyses of 16S rDNA sequences, the dominant strains of bacteria in the product were identified as Lactobacillus sakei, Enterobacter aerogenes, Lysinibacillus macroides, and Enterobacter xiangfangensis. Among these, Lactobacillus sakei was further identified as possessing the typical characteristics of a fermentative species, and thus probably plays a major role in the fermentation of dried salted Spanish mackerel.