Characterization of the dominant microorganisms responsible for the fermentation of dehulled maize grains into nsiho in Ghana
Nsiho (white kenkey) is a type of kenkey, a sour stiff dumpling, produced from fermented maize meal in Ghana. The dominant microorganisms responsible for the fermentation of nsiho were characterized by analysing samples from four traditional production sites at Anum in the Eastern Region of Ghana. During 48 h of steeping dehulled maize grains, the pH values decreased from 6.05 to 5.93 to 3.59 to 3.55, whilst titratable acidity increased from 0.02 to 0.03 to 0.27 to 0.32%. In the subsequent 12 h dough fermentation, the pH decreased from 6.02 to 5.80 to 3.52 to 3.46, whilst titratable acidity increased from 0.25 to 0.27 to 0.35 to 0.38%. The lactic acid bacteria population increased by 2 to 5 log units to concentrations of 107 to 108 CFU/ml during steeping and by 2 to 3 log units from 105 to 106 CFU/g to 108 to 109 CFU/g during dough fermentation. Yeasts counts increased by 3 to 4 log units during steeping
and by 2 to 4 log units during dough fermentation. The most frequently isolated lactic acid bacteria responsible for nsiho fermentation were identified as Lactobacillus fermentum (47.1%), Lactobacillus brevis (25%), Lactobacillus plantarum (14.42%), Pediococcus pentosaceus (8.65%) and Pediococcus acidilactici, (4.8%). The dominant yeasts species were Saccharyomyces cerevisiae (47.6%), Candida krusei (29.1%), Debaryomyces spp., (15%) and Trichosporon spp., (8.3%). This is the first study to report on the micororganisms involved in nsiho fermentation.
Key words: Nsiho, dehulled maize, kenkey, lactic acid bacteria, indigenous African fermented foods.