Application of refrigerated and frozen sorghum malt slurries in preservation of starter cultures of traditional fermented cereal-based beverages - a case of Obushera from Uganda

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Date
2020Author
Muzira Mukisa, Ivan
Serwanga, Arnold
Byakika, Stellah
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Show full item recordAbstract
Industrial production of traditional fermented beverages in developing countries is limited by lack of
commercial starter cultures. Saccharomyces (S.) cerevisiae MNC 21Y and Lactobacillus (L.) plantarum
MNC 21 were identied as starter cultures for a Ugandan cereal beverage, Obushera. However, they are
commercially unavailable due to lack of affordable appropriate propagating and preservation methods.
In this study the starters were propagated in sorghum malt slurries (30 °C for 24 h) and stored at 5 °C and
− 18 °C for 90 days. Viability and fermentation ability of the cultures was monitored.
Results
Viability was higher for starters stored at 5 °C (S. cerevisiae: 6 log cfu/g and L. plantarum: 7–9 log cfu/g
during 90 days) than those at -18 °C (S. cerevisiae: 2 cfu/g and L. plantarum: 4 log cfu/g after 30 days).
Refrigerated starters acidied Obushera (pH ≤ 4.5) faster (10–20 h) than frozen ones (18–24 h).
Refrigerating the starters in sorghum malt slurries preserves them for at least three months. This provides
an affordable option for starter commercialization and industrial production of traditional fermented
foods.