Traditional processing, microbiological, physiochemical and sensory characteristics of kwete, a Ugandan fermented maize based beverage

A survey was conducted to document the production methods of Kwete, a Ugandan fermented beverage in selected divisions in Kampala districts, Uganda. Microbial numbers in raw materials and during fermentation were enumerated using standard methods. Changes in selected physiochemical parameters: pH, titratable acidity (TA), ethanol and total soluble solids (TSS) were monitored at 24-hrs interval during 72hrs fermentation.Organoleptic properties of Kwete were also solicited from the producers. Similarities in raw material preparation and production techniques for Kwete were observed among the producers. Kwete was mainly produced from a mixture of maize and malted millet flour. All producers fermented the maize flours to produce raw sourdough for 24 hrs and roasted it before Kwete production. Fermentation was carried at ambient temperature in metallic drums. The duration of fermentation varied between 24 and72 hrs. Most households (80%) consumed Kwete within 24-48 hrs of fermentation. Coliforms, Yeasts and Lactic Acid Bacteria (LAB) numbers in maize flour and roasted sourdough varied between 1.59 and 5.24 log cfu-1. Yeasts and LAB numbers in raw sourdough and malted millet flour varied between 4.48 and 8.45 log cfu -1. No coliforms were detectable in raw sourdough. LAB numbers increased from 5.31 to 7.36 log cfu -1 during fermentation. Yeasts increased from 4.44 to 5.60 log cfu -1. Coliforms disappeared within 24 hrs of fermentation. The pH of maize flour droppedfrom pH 6.1 to 4.1 during sourdough production but increased to 4.89 during paste preparation. The final pH attained after 72 hrs of fermentation was 3.35. The TA increased from 0.84 to 1.43 % lactic acid. The TSS decreased from 9.02 to 5.87 o Brix. Ethanol content in Kwete increased from 4.85 to 13.30 % v/ v during fermentation. The various phases in Kwete production contribute significantly to the microorganisms involved in the fermentation. The high microbial numbers in addedmalted millet flour indicated that it is an important source of fermentationmicroorganisms during Kwete production