茶多酚对冰藏大黄鱼品质及微生物的影响

采用生物保鲜剂茶多酚对大黄鱼进行浸泡处理,研究了大黄鱼在冰藏保鲜过程中品质及微生物的变化。通过测定感官评分值、菌落总数、p H值、挥发性盐基氮(TVB-N值)及硫代巴比妥酸值(TBA值),评价大黄鱼在冰藏过程中品质变化,同时采用16 S r DNA克隆文库及限制性内切酶片段长度多态性(RFLP)技术对大黄鱼在冰藏条件下的腐败菌进行分析。结果表明,在冰藏过程中,茶多酚处理组的菌落总数、p H值、TVB-N值、TBA值均低于对照组,感官评分值优于对照组,大黄鱼在冰藏条件下货架期由12~16 d延长至20~24 d,茶多酚处理组保鲜效果较好。新鲜大黄鱼细菌种类比较丰富,达15种类型,而腐败后细菌种类明显减少,在腐败末期,对照组(20 d)的细菌种类有8种,其中假单胞菌属(Pseudomonas)和希瓦氏菌(Shewanella)为主要腐败菌,所占比例分别为43.7%和39.6%。而茶多酚处理组(24 d)细菌种类较对照组更少,其腐败菌主要为假单胞菌属(Pseudomonas),占细菌总量的76.8%。

Effects of Tea Polyphenols on Quality and Microorganisms of Pseudosciaena crocea during Iced Storage

The quality and microorganisms changes of large yellow croaker (Pseudosciaena crocea) during iced storage were studied using tea polyphenols as bio-preservatives in this study. The sensory evaluation values, total bacteria, pH value, total volatile base nitrogen (TVB-N value) and thiobarbituric acid (TBA value) were measured to evaluate the quality change of Pseudosciaena crocea. The 16 S rDNA clone library and restriction fragment length polymorphism (RFLP) were used to analyze the spoilage bacteria under iced storage condition. The results indicated that the total bacteria, pH value, TVB-N value and TBA value of the dipping group were significantly lower than those of the control group, and the sensory evaluation values of large yellow croaker were better than that of the control group. The shelf-life of dipping group extended from 12-16 days to 20-24 days at iced storage. So the dipping group had better preservation effect. The bacterial species of fresh pseudosciaen a crocea were abundant, reaching 15 types. And the species of bacteria in the spoilage fish decreased obviously. At the end of spoilage period, there were 8 species of bacteria in the control group (20 d), among which Pseudomonas and Shewanella were the dominant species, occupying 43.7% and 39.6% of the total microorganisms. And bacterial species in tea polyphenol dipping sample (24 d) were less than the control group. The dominant spoilage bacteria of dipping samples was Pseudomonas, taking a percentage of 76.8%.