不同贮藏温度下低盐腌渍大黄鱼鲜度及细菌菌相变化

为研究低盐腌渍大黄鱼的鲜度变化与其腐败细菌的关系,对低盐腌渍大黄鱼在5、15和25℃下贮藏过程中的感官、总挥发性盐基氮(TVBN)、硫代巴比妥酸(TBA)及菌落总数(TVC)进行了测定,并通过MIDI气相色谱法对其细菌菌相进行分析。结果表明,随着贮藏时间的延长,感官评分降低,TVBN、TBA、TVC显著(p<0.05)增长,5、15和25℃贮藏下的货架期分别为29、14、4 d。货架期终点时,感官评分、TVBN、TBA和TVC分别为(1.05±0.05)、(29.53±1.03)mg/100 g、(0.40±0.06)mg/100 g和(7.60±0.40)lg(cfu/g)。另一方面,大黄鱼中共分离鉴定出14种细菌,其特定腐败菌因贮藏温度变化而有所差异,在5℃贮藏下为彭氏变形杆菌,在15℃和25℃贮藏下为产气肠杆菌。通过比较,发现特定腐败菌比例与TVBN变化存在极显著相关性(p<0.01),而与TBA的相关性并不显著(p>0.05),说明肠杆菌科细菌是通过分解氮类并产生挥发性盐基氮从而导致低盐腌渍大黄鱼在贮藏过程中的腐败。 

Freshness and bacterial composition changes in lightly salted Pseudosciaena crocea stored at different temperatures

To study the correlation between the freshness and the spoilage bacteria of lightly salted Pseudosciaena crocea,the sensory,TVBN,TBA and TVC of lightly salted Pseudosciaena crocea stored at 5 ℃,15 ℃ and25 ℃ were investigated and its bacterial composition was analyzed using MIDI GC. The results showed that sensory quality decreased and there was significant(p<0.05) increase in TVBN,TBA and TVC with storage time. The shelf-lives of lightly salted Pseudosciaena crocea stored at 5 ℃,15 ℃ and 25 ℃ were determined as 29 d, 14 d, 4 d respectively. At the end of shelf-lives, sensory, TVBN, TBA and TVC were changed to(1.05±0.05),(29.53±1.03) mg/100 g,(0.40±0.06) mg/100 g and(7.60±0.40) lg(cfu/g),respectively.Besides,a complex bacterial composition consisting of 14 strains were isolated and identified. The specific spoilage organisms of lightly salted Pseudosciaena crocea stored at 5℃,15℃ and 25 ℃ were respectively Proteus penneri,Enterobacter aerogene and Enterobacter aerogene,belonging to Enterobacteriaceae. According to the comparison,it was proved that there was a significant correlation between the the specific spoilage bacteria ratio and TVBN( p < 0. 01), but the correlation with the TBA was not significant( p > 0. 05), which meant Enterobacteriaceae leads to the spoilage of lightly salted Pseudosciaena crocea through the decomposition of nitrogen and production of TVBN during storage.