Selection, use and the influence of starter cultures in the nutrition and processing improvement of ‘ogi’

Abstract

Starter cultures for ‘ogi’ production were selected with the aim of improving processing technique, lysine and methionine levels of ‘ogi’, a lactic acid fermented weaning food. Technological features of microorganisms from fermenting raw materials were screened to develop quality starter cultures. Lactobacillus brevis XO43 and Saccharomyces cerevisiae OY4 were finally selected and used as starter cultures in a pilot plant study. Fermentation with starter cultures showed constant final pH level of 3.35 in modified substrates after fermentation unlike spontaneously fermented; and significantly higher acidity (%TTA) indicative of faster fermentation. Addition of sugar (2%w/w) and soybean flours (1% w/w) also increased the acid levels during fermentation. Fermentation of dehulled maize grains fortified with glucose (2%w/w) alone by starter cultures shows the best quality in all the parameters considered except the available niacin yield. It is 24% higher than oven-dried ‘ogi’ flour from the traditional process and 11% higher than unprocessed whole maize grains. The methionine is 92% and 77% higher than the traditionally prepared ‘ogi’ and whole maize grains, respectively. The total amino acids level of the sample was 32% more than the traditionally fermented ‘ogi’ flour and 55% more than maize grains. Although, the soluble protein level was 23% lesser than the unfermented whole maize grains, it was 12% more than the dehulled maize substrate and ‘ogi’ from traditional process. Fermentation of corn into ‘ogi’ led to losses in the initial quantity of niacin. Starter cultures significantly improve the nutrients such as lysine, methionine, total amino acids, soluble protein and niacin more than spontaneous fermentation. Dehulling of grains, dewatering and oven drying significantly reduce nutrients. ‘Ogi’ fermentation process with the use of starter cultures and dehulled maize guarantee organoleptic qualities, improve ‘ogi’ production and create a better nutritional products.