Identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines

Rice wine is a rice-based alcoholic beverage produced through the fermentation of cereal grains, mainly rice, with microbial starters. However, the starter cultures sold in the market are often prepared based on empirical knowledge and thus varied in microbial compositions. Their exact microbial con...

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Main Author: Koay Meiwei
Format: Thesis
Language:English
English
Published: 2023
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https://eprints.ums.edu.my/id/eprint/40862/2/FULLTEXT.pdf
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spelling my-ums-ep.408622024-09-09T03:14:58Z Identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines 2023 Koay Meiwei TP500-660 Fermentation industries. Beverages. Alcohol Rice wine is a rice-based alcoholic beverage produced through the fermentation of cereal grains, mainly rice, with microbial starters. However, the starter cultures sold in the market are often prepared based on empirical knowledge and thus varied in microbial compositions. Their exact microbial contents are usually unknown, giving rise to the possibility of product quality and food safety issues. Although many researchers have identified the microbial communities in various rice wine starter cultures using molecular approaches, such information on sasad, a traditional starter culture for rice wine fermentation in Sabah, Malaysia, has not been published. Therefore, this research aims to identify the fungal and bacterial communities in sasad, study the physicochemical and microbiological changes in rice wines during fermentation, and determine the consumers’ acceptance of rice wines. The fungal and bacterial communities were identified through amplicon-based next-generation sequencing (NGS). Physicochemical properties including total soluble solids (TSS), alcohol content, total titratable acidity (TTA), pH, and colour, as well as microbiological properties such as total yeast and mould count (TYMC) and total lactic acid bacteria (LAB) count were determined. In addition, consumers’ acceptance of rice wines was determined through preference ranking and hedonic tests. A total of two fungal phyla (Mucoromycota and Ascomycota) with five genera (Mucor, Rhizopus, Saccharomycopsis, Wickerhamomyces, and Kodamaea) and two bacterial phyla (Proteobacteria and Firmicutes) with 10 genera (Kosakonia, Weissella, Enterobacter, Lactococcus, Pseudomonas, Bacillus, Chromobacterium, Paludibacterium, Enterococcus, and Gluconobacter) were identified as the core microbiota (relative abundance > 1.00%) in the sasad samples. Batch fermentation was successfully carried out using the sasad samples. The overall fermentation dynamics of rice wines (RWA, RWB, and RWC) produced using different sasad (SA, SB, and SC, respectively) exhibited similar trends. However, variations between the samples were still detected. After 28 days of ferementation, RWC showed the lowest TSS (22.9 ± 0.2 °Brix) and highest alcohol content (15.95 ± 0.07%), while RWA had the highest TTA (0.68 ± 0.04% lactic acid) and lowest pH (3.60 ± 0.01), demonstrating the effect of microbial compositions of sasad on the quality of final rice wines. All rice wine samples were acceptable to the panellists, while rice wines with darker shades of yellow and higher alcohol content or stronger alcoholic aroma were preferable. However, there is no significant difference (p > 0.05) in liking scores for taste, mouthfeel, and overall acceptance among the rice wine samples. The variation in consumers’ tastes suggested a potential for developing rice wines with various flavours to fulfil consumers’ needs. This research provides important insights into the potential roles of core microbiota found in sasad, the fermentation dynamics of rice wines, and the consumers’ acceptance of rice wines. The occurrence of opportunistic spoilage and pathogenic microorganisms in sasad emphasises the importance of developing sasad with well-defined microbial compositions for the consistent production of safe and high-quality rice wines. 2023 Thesis https://eprints.ums.edu.my/id/eprint/40862/ https://eprints.ums.edu.my/id/eprint/40862/1/24%20PAGES.pdf text en public https://eprints.ums.edu.my/id/eprint/40862/2/FULLTEXT.pdf text en validuser masters Universiti Malaysia Sabah Faculty of Food Science and Nutrition
institution Universiti Malaysia Sabah
collection UMS Institutional Repository
language English
English
topic TP500-660 Fermentation industries
Beverages
Alcohol
spellingShingle TP500-660 Fermentation industries
Beverages
Alcohol
Koay Meiwei
Identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines
description Rice wine is a rice-based alcoholic beverage produced through the fermentation of cereal grains, mainly rice, with microbial starters. However, the starter cultures sold in the market are often prepared based on empirical knowledge and thus varied in microbial compositions. Their exact microbial contents are usually unknown, giving rise to the possibility of product quality and food safety issues. Although many researchers have identified the microbial communities in various rice wine starter cultures using molecular approaches, such information on sasad, a traditional starter culture for rice wine fermentation in Sabah, Malaysia, has not been published. Therefore, this research aims to identify the fungal and bacterial communities in sasad, study the physicochemical and microbiological changes in rice wines during fermentation, and determine the consumers’ acceptance of rice wines. The fungal and bacterial communities were identified through amplicon-based next-generation sequencing (NGS). Physicochemical properties including total soluble solids (TSS), alcohol content, total titratable acidity (TTA), pH, and colour, as well as microbiological properties such as total yeast and mould count (TYMC) and total lactic acid bacteria (LAB) count were determined. In addition, consumers’ acceptance of rice wines was determined through preference ranking and hedonic tests. A total of two fungal phyla (Mucoromycota and Ascomycota) with five genera (Mucor, Rhizopus, Saccharomycopsis, Wickerhamomyces, and Kodamaea) and two bacterial phyla (Proteobacteria and Firmicutes) with 10 genera (Kosakonia, Weissella, Enterobacter, Lactococcus, Pseudomonas, Bacillus, Chromobacterium, Paludibacterium, Enterococcus, and Gluconobacter) were identified as the core microbiota (relative abundance > 1.00%) in the sasad samples. Batch fermentation was successfully carried out using the sasad samples. The overall fermentation dynamics of rice wines (RWA, RWB, and RWC) produced using different sasad (SA, SB, and SC, respectively) exhibited similar trends. However, variations between the samples were still detected. After 28 days of ferementation, RWC showed the lowest TSS (22.9 ± 0.2 °Brix) and highest alcohol content (15.95 ± 0.07%), while RWA had the highest TTA (0.68 ± 0.04% lactic acid) and lowest pH (3.60 ± 0.01), demonstrating the effect of microbial compositions of sasad on the quality of final rice wines. All rice wine samples were acceptable to the panellists, while rice wines with darker shades of yellow and higher alcohol content or stronger alcoholic aroma were preferable. However, there is no significant difference (p > 0.05) in liking scores for taste, mouthfeel, and overall acceptance among the rice wine samples. The variation in consumers’ tastes suggested a potential for developing rice wines with various flavours to fulfil consumers’ needs. This research provides important insights into the potential roles of core microbiota found in sasad, the fermentation dynamics of rice wines, and the consumers’ acceptance of rice wines. The occurrence of opportunistic spoilage and pathogenic microorganisms in sasad emphasises the importance of developing sasad with well-defined microbial compositions for the consistent production of safe and high-quality rice wines.
format Thesis
qualification_level Master's degree
author Koay Meiwei
author_facet Koay Meiwei
author_sort Koay Meiwei
title Identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines
title_short Identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines
title_full Identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines
title_fullStr Identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines
title_full_unstemmed Identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines
title_sort identification of microbial communities in rice wine traditional starter (sasad) and fermentation of rice wines
granting_institution Universiti Malaysia Sabah
granting_department Faculty of Food Science and Nutrition
publishDate 2023
url https://eprints.ums.edu.my/id/eprint/40862/1/24%20PAGES.pdf
https://eprints.ums.edu.my/id/eprint/40862/2/FULLTEXT.pdf
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