鲫鱼贮藏过程中微生物菌相PCR-DGGE分析及其防腐保鲜

采用聚合酶链式反应-变性梯度凝胶电泳(polymerase chain reaction-amplification and denaturing gradient gel electrophorsis,PCR-DGGE)技术,分析4℃冷藏条件下鲫鱼肌肉和鱼鳃的菌相组成及变化,并利用不同浓度(效价分别为67 608、32 359、2 239、1 820、1 157 IU/m L)抗菌脂肽溶液对鲫鱼进行浸泡处理,以未处理作为对照,分别测定其菌落总数、挥发性盐基氮(total volatile basic nitrogen,TVB-N)、p H值和硫代巴比妥酸(thiobarbituric acid,TBA)等指标,评价抗菌脂肽对鲫鱼冷藏保鲜效果。结果表明:鲫鱼贮藏过程中的微生物具有多样性,PCRDGGE技术确定气单胞菌属(Aeromonas sp.)、假单胞菌属(Pseudomonas sp.)、不动杆菌属(Acinetobacter sp.)和热杀索丝菌属(Brochothrix thermosphacta)为鲫鱼鱼肉的主要腐败菌群,荧光假单胞菌是鲫鱼贮藏过程中的优势腐败菌。而棉子糖乳球菌属(Lactococcus raffinolactis)、从毛单胞菌属(Comamonas sp.)和气单胞菌属(Aeromonas sp.)为鲫鱼鱼鳃的主要腐败菌群,表明鱼肉和鱼鳃在贮藏过程中,导致腐败的主要腐败菌群有一定差异性。同时,不同浓度的抗菌脂肽对鲫鱼均有明显的防腐保鲜作用,有效抑制了鲫鱼菌落总数、TVB-N值和TBA值的增加以及p H值的升高。其中,高浓度抗菌脂肽(效价为67 608 IU/m L)在4℃贮藏条件下使鲫鱼的货架期延长了6 d,说明抗菌脂肽对鲫鱼具有良好的保鲜作用,能明显延缓鲫鱼的腐败变质。

PCR-DGGE Analysis of Microbial Community Composition and Preservation of Crucian Carp during Storage

The microbial community structure of crucian carp was studied by polymerase chain reaction-amplification and denaturing gradient gel electrophorsis (PCR-DGGE) during storage at 4 ℃. Meanwhile, in order to use it for the preservation of crucian carp, the antimicrobial effect of antimicrobial lipopeptide was evaluated through the determination of total bacterial counts, total volatile basic nitrogen (TVB-N), pH and thiobarbituric acid (TBA). The results showed that the microbial community of crucian carp was diverse during storage. Specifically, Aeromonas sp., Pseudomonas sp., Acinetobacter sp. and Brochothrix thermosphacta were the main spoilage microorganisms, and Pseudomonas fluorescens was the dominant spoilage microorganism in the flesh of the fish, while Lactococcus raffinolactis, Comamonas sp. and Aeromonas sp. were the main spoilage microorganisms in the gill. These results also indicated that although the microbial community compositions in the flesh and gill of crucian carp were different, but they showed a similar trend during storage. On the other hand, the antimicrobial lipopeptide at different concentrations significantly inhibited the increase of total bacterial counts, TVB-N, pH and TBA. The lipopeptide at a concentration of 67 608 IU/mL extended the shelf-life of crucian carp by up to 6 days during storage at 4 ℃. All these findings demonstrated that the antimicrobial lipopeptide can significantly inhibit the growth of spoilage microorganisms in crucian carp, thus being a promising preservative.