Isolation and characterization of lactic acid bacteria from Yan-dong-gua(fermented wax gourd), a traditional fermented food in Taiwan

• Main Authors: Wei-Tse Lan, 藍偉哲
• Other Authors: Yi-Sheng Chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/91873938677193573429

碩士 === 銘傳大學 === 生物科技學系碩士班 === 98 === Yan-dong-gua (fermented wax gourd; a traditional fermented food in Taiwan) samples were collected at five time intervals from a fixed fermenting bucket. 85 cultures of lactic acid bacteria (LAB) were isolated from Yan-dong-gua samples, and the isolates were divided into classes by phenotype and then groups by restriction fragment length polymorphism analysis and sequencing of 16S rDNA. Phenotypic and biochemical characteristics identified two bacterial groups (A and B) and showed that Weissella cibaria was the major LAB found during the initial fermentation of yan-dong-gua. However, it was mostly replaced by W. paramesenteroides after 5 days of fermentation. All isolated LAB were able to grow in MRS broth containing 6% NaCl. These results suggest that W. cibaria and W. paramesenteroides are the main LAB present during the fermentation of yan-dong-gua. In addition, the antifungal activities of 85 strains against the four fungal species, Penicillium oxalicum, Aspergillus flavus, Asp. sydowii and Mucor racemosus, were determined. Inhibitory activity against at least one or more fungal species was observed with 27 W. cibaria and 11 W. paramesenteroides strains. W. cibaria 861006 and W. paramesenteroides 860509 showed greater inhibitory activities and were therefore selected for further analysis and the application test. The results suggested that the antifungal activities of the selected strains originated from organic acids. The results of the application tests indicated that the growth of fungal strains on grape and papaya surfaces could be effectively inhibited by 861006 and 860509 strains. The findings obtained in this study suggest the potential use of W. cibaria 861006 and W. paramesenteroides 860509 as bioprotective agents against fungi for agricultural purposes or ready-to-eat fresh fruit and vegetable products.