EVALUATION OF MONO AND CO-CULTURAL FERMENTATION ON THE NUTRITIONAL AND ANTI-NUTRITIONAL COMPOSITION OF KUNU; A FERMENTED MILLET BASED FOOD

Abstract

This study was designed to investigate the effect of mono and co-cultural fermentation on the nutritional and anti-nutritional composition of kunu; a fermented millet- based food. Raw millet and hawked kunu samples were purchased from five (5) different locations in Akure metropolis. The raw millet was processed into kunu at the Postgraduate research Laboratory FUTA. The processing of raw millet to kunu was achieved through pasteurization, while unpasteurized served as a control. The isolation and identification of microorganisms associate with raw millet and kunu were carried out using standard microbiological techniques. The identities of the selected microorganisms were further authenticated via 16SrRNA sequence analysis. Fermenting millet gruel inoculated with the mixed cultures (Lb plantarum, Lb. fermentum, Saccharomyces cerevisiae and B. subtili) as the fermentation process. Fermented millet gruel inoculated with the starter culture and naturally fermented samples decreased in pH. The percentage protein, ash and moisture content of kunu were higher than the values recorded for the naturally processed kunu. The highest protein of 4.01% and ash content of 2.54% was observed in kunu produced with S. cerevisiae and Lb. plantarum. Nitrogen, calcium, potassium and magnesium of the kunu produced with inocula increased compared with the kunu obtained via naturally fermentation. The highest nitrogen of 0.97 mg/100ml, potassium of mg/100ml, magnesium of 33 mg/100ml and calcium of 11.02 mg/100ml were obtained in the sample processed by the combination of S. cerevisiae and Lb. plantarum. There was reduction in oxalate and tannin content in the inoculated samples compared with kunu produced through natural fermentation. The lowest oxalate of 15.00 mg/kg and tannin of 23.03 mg/kg was recorded in sample with S. cerevisiae and Lb. plantarum. Kunu prepared from different co-cultural fermentation of Lb. plantarum and Lb. fermentum was significantly higher in phenolic content of 3.33 mg/g and flavonoid content of 1.40 mg/g than natural fermentation. The highest vitamin C content of 9.00 mg/100g was recorded in sample with S. cerevisiae and Lb. plantarum. The findings of the study revealed that the co-cultural fermentation of S. cerevisiae and Lb. plantarum posses the ability to increase nutritional composition and reduce the anti- nutritional composition of kunu.