Comparative assessment of fermentation techniques useful in the processing of ogi

Abstract

Ogi is processed traditionally by the use of 'uncontrolled' spontaneous fermentation of maize, sorghum and millet. In this study, traditionally applied spontaneous fermentation was compared with accelerated batch fermentation (or back-slopping) and the use of starter cultures to initiate fermentation. Lactic acid bacteria populations comprised ‡95% of the total viable bacteria and remained prominent throughout the fermentations, while number of moulds and coliform bacteria declined as the fermentation progressed. The fermentation method involving the application of starter culture helps most to control the prevalence of coliforms and moulds. Lactic acid bacteria, such as Lactococcus raffinolactis, Pediococcus sp., Pediococcus pentosaceus, Lactobacillus plantarum, Lb. suebicus and Lb. brevis, were isolated at different processing stages of ogi using accelerated batch fermentation (back-slopping) technique. Highest increase in acidity was observed immediately after wet-milling and sieving fermenting maize grains at 28 and 48 h. Sharp increases in the reducing sugar levels were noted between 24 and 28 h of fermentations during wet-milling and sieving processes.

Bacterial Diversity and Mycotoxin Reduction During Maize Fermentation (Steeping) for Ogi Production

“…Similar spectra and even more species of LAB excluding L. paraplantarum and P. claussenii have been previously reported in ogi made from a range of cereals including guinea-corn, maize, millet, and sorghum (Teniola and Odunfa, 2002; Teniola et al, 2005; Adebayo and Aderiye, 2007; Adebayo-tayo and Onilude, 2008; Oguntoyinbo et al, 2011; Omemu, 2011; Banwo et al, 2012; Oguntoyinbo and Narbad, 2012). L. plantarum and various species of Lactococcus and Leuconostoc were previously reported in maize steep liquor at 24–72 h by Oyedeji et al (2013).…”

“…The isolates obtained on PCA ( n = 51) represented aerobic or facultatively anaerobic species while those on MRS agar ( n = 91) were LAB and represented obligate or facultative anaerobic homofermentative cocci or heterofermentative cocci and rods. Preliminary identification tests of all the 142 isolates suggested the LAB isolates were Gram-positive, catalase negative and non-motile (Odunfa and Adeyele, 1985; Teniola and Odunfa, 2002; Teniola et al, 2005) and belonged to Lactobacillus and Pediococcus , while other bacteria belonged to Bacillus , Enterococcus and a range of rod-shaped bacteria.…”

“…Several authors have reported on ogi production from various varieties of maize (white and yellow), from guinea corn, millet and sorghum after steeping for either 24, 48, 72, or 96 h (Odunfa and Adeyele, 1985; Teniola and Odunfa, 2002; Teniola et al, 2005; Adebayo and Aderiye, 2007; Adebayo-tayo and Onilude, 2008; Dike and Sanni, 2010; Omemu, 2011; Banwo et al, 2012; Oyedeji et al, 2013). Usual practice in the local/traditional setting, however, is that maize is steeped for at least 48 h and may extend to 96 h. In order to understand the ecology of species and promote biotechnology through beneficial strain selection for improved ogi production, microbial communities associated with spontaneous maize fermentation to ogi have been characterized and studied.…”

“…Usual practice in the local/traditional setting, however, is that maize is steeped for at least 48 h and may extend to 96 h. In order to understand the ecology of species and promote biotechnology through beneficial strain selection for improved ogi production, microbial communities associated with spontaneous maize fermentation to ogi have been characterized and studied. The majority of the studies considered microbial diversity in mashed fermented maize grains (Teniola et al, 2005; Adebayo and Aderiye, 2007; Omemu, 2011) while others characterized fermenters from souring ogi samples (Odunfa and Adeyele, 1985; Teniola and Odunfa, 2002; Adebayo-tayo and Onilude, 2008; Oguntoyinbo et al, 2011; Banwo et al, 2012; Oguntoyinbo and Narbad, 2012); only Oyedeji et al (2013) examined maize steep liquor of 24–72 h for fermenter diversity. From the aforementioned studies, Lactobacillus and Leuconostoc have been reported as the occurring genera of lactic acid bacteria (LAB) in maize steep liquor and fermented/souring ogi while Pediococcus was only reported in fermented/souring ogi .…”

“…Past studies with respect to ogi production focused mostly on studying microbial diversity and the roles of fermenters against natural microbial contaminants in ogi production (Odunfa and Adeyele, 1985; Teniola and Odunfa, 2002; Teniola et al, 2005; Adebayo and Aderiye, 2007; Adebayo-tayo and Onilude, 2008; Oguntoyinbo et al, 2011; Omemu, 2011; Banwo et al, 2012; Oguntoyinbo and Narbad, 2012; Oyedeji et al, 2013). There are also reports available on mycotoxin reduction mediated by single or combined cultures of LAB and other fermentation bacteria artificially inoculated into maize and other grains (Mokoena et al, 2005; Shetty and Jespersen, 2006; Oluwafemi and Da-Silva, 2009; Cho et al, 2010; Nyamete, 2013; Zhao et al, 2015).…”