Microbiological and physico-chemical changes during fermentation of maize for masa production

Abstract

Samples of traditionally fermenting maize meal popularly called masa were collected from local producers of masa in Ibadan, Oyo State, Nigeria and were analysed for pH, total titratable acidity (TTA), microbiological changes and proximate analysis. The sensory properties (colour, texture, taste, sourness, appearance and general acceptability) were also carried out on a nine point hedonic scale. The values obtained were compared with the starter culture fermenting maize meal prepared in the laboratory. The physico-chemical changes during the traditional and the laboratory prepared fermenting maize meal were observed at 6 h interval during the fermentation process. There was decrease in pH; the pH of the traditional fermenting maize meal ranged between 5.98 ± 0.27 to 3.95 ± 0.05 while the pH of the laboratory prepared fermenting maize meal ranged between 6.4 ± 0.36 to 4.3 ± 0.03. There was increase in TTA during the fermentation period; in the traditional fermenting maize meal the TTA ranged between 0.144 ± 0.02 to 0.792 ± 0.08 and it ranged between 0.054 ± 0.02 to 0.252 ± 0.00 in the laboratory fermenting maize meal. Microorganisms associated with the traditional fermentation of masa wereLactobacillus plantarum, Pediococcus acidilactici, Lactobacillus fermentum andSaccharomyces cerevisiae. In all the fermenting maize meal samples collected and the laboratory prepared maize meal samples inoculated with starter organisms, an increase in the microbial load counts (log10cfu/ml) was observed as the fermentation time progresses, 3.02 to 6.41 (on De Mann Rogosa-Sharpe agar), 2.99 to 3.62 (on malt extract agar), 4.18 to 7.00 (on nutrient agar) during the traditional fermentation, in the laboratory prepared maize meal samples inoculated with starter organisms, the microbial load counts (log10cfu/ml) ranged between 4.01 to 9.05. The laboratory prepared maize meal samples inoculated with starter organisms only showed minimal changes in their proximate composition as compared with the traditionally fermented samples collected. The statistical analysis of the sensory attributes revealed consumer’s acceptance of the product inoculated with the starter organisms. Key words: Proximate analysis, TTA, physico-chemical changes, masa, starter organisms.