PCR-DGGE分析鲜切莲藕冷藏过程中的菌相变化

Changes in Microbial Flora of Fresh-cut Lotus Root during Cold Storage Based on PCR-DGGE Technology

为明确鲜切莲藕的微生物腐败机制,基于PCR-DGGE技术分析其冷藏过程中的菌相变化。鲜切莲藕样品于4℃冷藏,每间隔3 d取出,PCR扩增其16S r DNA的V3高变区,将产物进行变性梯度凝胶电泳(DGGE),并对优势条带进行回收和测序。结果表明,冷藏过程中鲜切莲藕的菌相结构发生明显变化,冷藏6~9 d为其腐败的关键时间点,其中假单胞菌属、伯氏致病杆菌、克雷伯氏肺炎杆菌为主要腐败菌,尤其是假单胞菌属在冷藏后期最易增殖,逐渐成为优势腐败菌,可作为鲜切莲藕产品腐败评价或快速检测的重要指示菌。

In order to clear the microbial spoilage mechanism of fresh cut lotus root, changes of its microbial flora during cold storage was investigated using PCR-DGGE technology. The fresh-cut lotus root was refrigerated in 4 ℃ and taken out for amplifying the V3 area of 16 s r DNA sequence at every 3 days, then the PCR products were analyzed by DGGE and dominant bands were recovered and sequenced. The results showed that microbial flora of fresh cut lotus root changed obviously during cold storage and 6 ~9 days was the key point of spoilage. And the main spoilage bacteria of refrigerated lotus root were Pseudomonas sp., Xenorhabdus bovienii, Klebsiella pneumoniae, especially Pseudomonas sp.was gradually became the dominant spoilage bacteria during the latter of cold storage and can be used as an indicator for spoilage evaluation or detection of fresh-cut lotus root products.