Microbiological and aromatic characteristics of fermented maize doughs for kenkey production in Ghana

A very uniform microflora was demonstrated in 15 samples of fermented maize dough from different larger commercial production sites. At the advanced stage of fermentation, more than 96% of the bacteria present were morphologically and biochemically uniform, obligatively heterofermentative lactobacilli occurring in concentrations about 10(9) cfu/g. Yeast occurred in levels of about 10(6) cfu/g, dominated by Candida and Saccharomyces spp. Studies on microbial successions indicated a selection towards a micropopulation dominated by lactic acid bacteria. The Gram-negative bacteria, catalase-positive Gram-positive bacteria and moulds underwent three to four decimal reductions during the early phase of the process. The aroma components detected were dominated by lactic acid, acetic, butyric and propionic acids. Volatile aroma components demonstrated by gas chromatography and mass spectrometry were characteristic for lactic acid bacteria with acetoin and related products as typical examples.