冬瓜生腌过程细菌种群变化及其品质相关性

Bacteria Community Changes and Its Quality Related in Raw Process of Pickled Wax Gourd

采用16S rDNA基因克隆文库的方法,对生腌冬瓜腌制体系的微生物多样性、优势种群及其相关品质变化过程进行分析。结果表明:冬瓜生腌开始时优势细菌为肠杆菌属、乳球菌属和魏斯氏菌属;早期阶段优势菌为戊糖片球菌;腌制30 d时优势菌属变成了肠杆菌属和片球菌属;在腌制中后期微生物组成基本稳定,其中片球菌属、魏斯氏菌属和枝芽孢杆菌属为优势菌属。冬瓜生腌制过程中pH值和亚硝酸盐质量分数下降,最低值分别为3.7和0.5 mg/kg,盐度稳定在7.0左右,细菌总数和乳酸菌总数由下降至最后稳定的过程,腌制中后期乳酸菌总数稳定在1.0×107 cfu/mL左右。冬瓜生腌过程检测到的乳球菌、片球菌和枝芽孢杆菌等菌属对维持腌冬瓜质量具有重要意义。

The microbial community diversity, predominant species and its related characters ofthe product were investigated during the fermentation process of pickled wax gourd using the16S rDNA clone library. The results showed that in the pickling system Enterobacter, Lactococcus and Weissella are the predominant microbial community at earlier phase. After 15 daysof fermentation, the dominant population has changed to be Pediococcus pentosaceus, on day30 Enterobacter and Pediococcus become to be the predominant species. In the later stage ofpickling, the community system is stable, and Pediococcus, Weissella and Virgibacillus arethe major microbial species. At the same time, the pH value and nitrite concentration of pickledwaxgourd samples had been decreasing, its minimum values reached 3.7 and 0.5 mg/kg, respectively. The salinity value was finally stable in 7.0%. The total population of bacteria andlactic acid bacteria (LAB) changed from the high level to stable, the population of LAB was 1.0×107 cfu/mL at the later phase of pickled. Some species including Lactococcus, Pediococcusand Virgibacillus detected in the pickled wax gourd are very significant microorganisms inkeeping the quality of the product. These experimental results can also provide the critical ba-sis for the microbial ecosystem study and quality control of pickled wax gourd processing.