Microbiological assessment and nutritional quality of ogi made from maize, sorghum and their mixture

Abstract

This study was designed to evaluate the microbiological assessment and nutritional quality of ogi made from maize, sorghum and their mixture. Gruels produced from these grains and their mixture were fermented for 72 hours. The pH, total titratable acidity, temperature of the fermenting samples, proximate analysis and the organoleptic properties were also monitored on daily basis. Microbial counts increased in all the samples in which the mixed sample and sorghum sample had the highest and the lowest microbial counts throughout the fermentation period respectively. The microorganisms isolated were Lactobacillus acidophilus, Streptococcus mutans, Enterococcus faecium, Escherichia coli, Enterobacter agglomerans, Corynebacterium amycolatum, Staphylococcus aureus, Bacillus subtilis, Aerobacter aerogenes, Citrobacter freundii, Klebsiella oxytoca, Brevibacterium linens, Penicillium citrinum, Aspergillus niger, Fusarium graminearum, Candida krusei, Saccharomyces cerevisiae, Rhodotorula mucilaginosa and Sceudosporium apiospermum. The pH of the fermenting samples decreased with TTA increase in which sorghum and mixed samples had the highest and the lowest pH of 4.3 and 3.1 when fermented while the least and the highest TTA were obtained from the same samples respectively. Moisture and protein contents increased after fermenting the samples with the highest from the mixture and maize samples. The fat, ash, crude fibre and carbohydrate contents decreased in all the ogi samples. The odour and the taste were rated strongly acceptable and sour respectively in all the samples while the colour was variably rated. The improvements observed in the nutritional contents of ogi from unmixed maize and sorghum grains suggest their potential in the formulation of complementary weaning foods for infants.