Dataset Information

Distinctive Formation of Volatile Compounds in Fermented Rice Inoculated by Different Molds, Yeasts, and Lactic Acid Bacteria.

ABSTRACT: Rice has been fermented to enhance its application in some foods. Although various microbes are involved in rice fermentation, their roles in the formation of volatile compounds, which are important to the characteristics of fermented rice, are not clear. In this study, diverse approaches, such as partial least squares-discriminant analysis (PLS-DA), metabolic pathway-based volatile compound formations, and correlation analysis between volatile compounds and microbes were applied to compare metabolic characteristics according to each microbe and determine microbe-specific metabolites in fermented rice inoculated by molds, yeasts, and lactic acid bacteria. Metabolic changes were relatively more activated in fermented rice inoculated by molds compared to other microbes. Volatile compound profiles were significantly changed depending on each microbe as well as the group of microbes. Regarding some metabolic pathways, such as carbohydrates, amino acids, and fatty acids, it could be observed that certain formation pathways of volatile compounds were closely linked with the type of microbes. Also, some volatile compounds were strongly correlated to specific microbes; for example, branched-chain volatiles were closely link to Aspergillus oryzae, while Lactobacillus plantarum had strong relationship with acetic acid in fermented rice. This study can provide an insight into the effects of fermentative microbes on the formation of volatile compounds in rice fermentation.

SUBMITTER: Park MK

PROVIDER: S-EPMC6600562 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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Distinctive Formation of Volatile Compounds in Fermented Rice Inoculated by Different Molds, Yeasts, and Lactic Acid Bacteria.

Park Min Kyung MK Kim Young-Suk YS

Molecules (Basel, Switzerland) 20190605 11

Rice has been fermented to enhance its application in some foods. Although various microbes are involved in rice fermentation, their roles in the formation of volatile compounds, which are important to the characteristics of fermented rice, are not clear. In this study, diverse approaches, such as partial least squares-discriminant analysis (PLS-DA), metabolic pathway-based volatile compound formations, and correlation analysis between volatile compounds and microbes were applied to compare meta ...[more]

PMID: 31195658

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Project description:Single and mixed starter cultures of lactic acid bacteria (LAB): Weissella confusa MNC20, Lactobacillus plantarum MNC21, Lactococcus lactis MNC24 and Lactobacillus fermentum MNC34 and yeasts: Issatchenkia orientalis MNC20Y and Saccharomyces cerevisiae MNC21Y were used to produce Obushera, a fermented sorghum beverage. Microbial counts, pH, sugars, organic acids, and volatile compounds in starter culture and spontaneous fermentations were monitored during 48 hrs. Maximum counts of LAB (8.4-9.4 log cfu g-1) and yeasts (7.5 ± 0.1 cfu g-1) starter cultures were attained in 6-48 hrs. Weissella confusa, Lc. lactis, and Lb. fermentum showed possible acid sensitivity while I. orientalis produced surface films. LAB starter cultures and their combinations with S. cerevisiae lowered pH from 5.83 to <4.5 (3.50-4.13) in a shorter time (12 hrs) than spontaneous fermentations (24 hrs). Lactococcus lactis and W. confusa metabolized glucose the fastest (p < .05) during the first 6 hrs. Lactobacillus fermentum, Lb. plantarum, and S. cerevisiae utilized glucose and maltose concurrently. Lactobacillus plantarum and S. cerevisiae additionally utilized fructose. S. cerevisiae metabolized sugars the fastest (p < .05) during the first 12-24 hrs. Lactobacillus plantarum and W. confusa produced the highest (p < .05) amounts of lactate (5.43 g kg-1) and diacetyl (9.5 mg kg-1), respectively. LAB also produced acetate, ethanol, acetaldehyde, acetone, and acetoin. Coculturing LAB with S. cerevisiae reduced (p < .05) lactate and diacetyl yield. Yeasts produced high amounts of acetaldehyde and methyl alcohols. Issatchenkia orientalis produced higher (p < .05) amounts of 2-methy-1-propanol and 3-methyl-1-butanol than S. cerevisiae. Combinations of LAB with S. cerevisiae produced a profile flavor compounds close to that of spontaneously fermented Obushera. These combinations can be adopted for controlled fermentation of Obushera and related fermented cereal products.

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Dataset Information

Distinctive Formation of Volatile Compounds in Fermented Rice Inoculated by Different Molds, Yeasts, and Lactic Acid Bacteria.

Publications

Distinctive Formation of Volatile Compounds in Fermented Rice Inoculated by Different Molds, Yeasts, and Lactic Acid Bacteria.

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