Microbiology and Biochemistry of Duma: Fermented Honey Drink of Southern Sudan
Microbiology and Biochemistry of Duma: Fermented Honey Drink of Southern Sudan
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Date
2015-06-17
Authors
Nada Hassan
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Publisher
UOFK
Abstract
Duma is a fermented honey drink commonly found in southern Sudan.
Ethanol content of collected samples ranged from 4.3% to 10.2%, and total acidity
ranged from 0.73% to 1.08%, while volatile fatty acids were very low.
Laboratory fermentation showed that duma fermentation is an alcoholic
fermentation as shown by an increase in yeast count producing 8.25% ethanol. The
fermentation is also a lactic fermentation, which is indicated by the increase in
lactic bacteria dropping the pH from 4.9 to 3.02. During the process total acidity
increased from 0.12% to 0.8%.
Tentative identification of microorganisms showed that yeast isolates belonged to
Schizosaccharomyces pombe, Schizosaccharomyces octosporus, and
Saccharomyces cerevisiae, while lactic acid bacteria belonged to Lactobacillu
brevis, L. fermentum, L. plantarum and Pediococcus damnosus.
Microorganisms that were responsible for fermentation were used as
starter culture in laboratory fermentation. The result indicated that
fermentation by this method is faster than the traditional
fermentation. Metabolic products were characterized by an increase in
ethanol to 9.86% and a total acidity of 0.75%. The pH dropped from 4.7
to 3.0, and volatile fatty acids were very low.Physiological studies have shown that yeast isolates were thermophilic
and osmotolerant. With respect to salt tolerance, all isolates were able
to grow at 10% sodium chloride.
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University of khartoum