Production of organic flavor compounds by dominant lactic acid bacteria and yeasts from Obushera, a traditional sorghum malt fermented beverage
Loading...
Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Food science & nutrition
Abstract
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.
Description
Keywords
Cereal fermentation, Lactic acid bacteria, Obushera, Sorghum, Starter cultures, Yeasts
Citation
Mukisa, IM, Byaruhanga, YB, Muyanja, CM, Langsrud, T., & Narvhus, JA (2017). Production of organic flavor compounds by dominating lactic acid bacteria and yeasts from Obushera, a traditional sorghum malt fermented beverage. Food science & nutrition , 5 (3), 702-712. DOI: 10.1002/fsn3.450