Parameters of processing and microbial changes during fermentation of borde, a traditional Ethiopian beverage

Abstract

Samples of borde from open markets at five localities in southern Ethiopia showed average aerobic mesophilic count (AMC), lactic acid bacteria (LAB) and yeast counts of 9.9, 10.1, and 8.1 log CFU g-1 respectively. Enterobacteriaceae (EB) were <1 to 3.5 log CFU g-1. The pH was 3.92±0.14. During the traditional production of borde with its four phases, the proportions of ingredients and cooking temperature were measured. Development of pH, titratable acidity, microbial load and mash temperature were monitored at 6 h intervals. The yield and production cost were assessed. The initial pH of 6.01 fell to 3.84 at end of Phase I. However, the pH increased at the start of Phase II, III and IV fermentations due to addition of malt and/or unmalted cooked ingredients and then decreased to below pH 4.0 at the end of each phase. During Phase I, EB increased from 5.1 to 7.7 log CFU g-1 at 24 h, but were not detected after 48 h. AMC, LAB and yeasts increased from their initial 6.5, 5.3 and 4.5 respectively to 10.5, 10.6 and 7.5 log CFU g-1 at end of Phase I. The AMC of cooked ingredients were 4.6-4.9 log CFU g-1, while EB, yeasts and LAB were not detected. After mixing the cooked ingredients and malt, the AMC, LAB and yeasts increased from 7.1, 6.3 and 5.4 at Phase II to 10.5, 10.5 and 8.6 log CFU g-1 in borde, respectively. EB decreased from 5.2 to <1 log CFU g-1 at Phase II and were not detected in borde. The major roles of Phase I, II, III and IV are production of an acidic fermented mass, bulk starter production, main and corrective fermentations respectively. Keywords: traditional technology; cereal fermentation; LAB; beverage; borde; Ethiopia



Keywords: traditional technology; cereal fermentation; LAB; beverage; borde; Ethiopia


J Food Tech in Africa (2002) 7, 85-92