Microorganisms in yeast cakes controlling the quality and taste of traditional fermentation products

• Main Authors: Tran, Thi Le Quyen, Bui, Thi Viet Ha, Dao, Thi Luong, Dinh, Thuy Hang, Duong, Van Hop
• Format: Article
• Language: English
• Published: Hanoi national University 2016
• Subjects: yeast cake; traditional fermentation; alcohol fermentation
• Online Access: http://repository.vnu.edu.vn/handle/VNU_123/11237
• Institution: Vietnam National University, Hanoi

Alcohol fermentation was carried out with sticky rice using 15 most popular sorts of yeast cakes in Vietnam to produce different kinds of alcoholic beverages. The products were obtained by traditional distillation method and compared with each other for flavour and taste according to the standard qualification scale for alcoholic products. It revealed that Ruou Can yeast cake which has been widely used for hundreds years by local communities yielded the best product and therefore was selected for further studies. From this yeast cake, two yeast strains were first time isolated and identified as Saccharomyces cerevisiae and Saccharomycopsis fibuliger based on morphology and 26S rDNA D1/D2 sequencing analyses. A sort yeast cake remade by using these two yeast strains yielded alcoholic product as good as the product obtained from using Ruou Can yeast cake. PCR/DGGE analysis of 16S rDNA (for the Prokaryotes) and 18S rDNA (for the Eukaryotes) showed differences in structures of microbial communities in the studied yeast cakes. However, in all cases, Saccharomyces sp., Saccharomycopsis sp., and Lactobacillus sp. accounted for the most abundant populations. Interestingly, the both best sorts of yeast cakes, i.e the Ruou Can yeast cake and the remade yeast cake, contain mainly these groups of microorganisms.