Effects of Fermentation and Extrusion on the Proximate Composition of Corn-Groundnut Flour Blends

Abstract

Effect of fermentation and extrusion on the proximate composition of corn-groundnut flour blends were investigated. The corn-groundnut flour blends were prepared to six combinations (100:0, 90;10, 80:20, 70:30, 60:40 and 50:50) during extrusion. During fermentation of the extrudates, a total number of 14 micro-organisms were isolated; these comprises of eight (8) bacteria, five (5) moulds and one (1) yeast. They include Bacillus subtilis, Bacillus licheniformis, Leuconostoc mesenteroides, Klebsiella aerogenes, Staphylococcus aureus, Lactobacillus plantarum, Lactobacillus brevis, Micrococcus luteus, Rhizopus nigricans, Aspergillus niger, Aspergillus saprophyticus, Saccharomyces cerevisiae, Penicillium chrysogenum and Geotrichum candidum. The pH and the total titratable acidity (TTA) varied significantly during fermentation. Carbohydrate contents significantly increased in all the fermented extrudated samples. The moisture content of the unfermented extruded samples decreased (p< 0.05) significantly when compared to the raw blends. Crude fibre and fat contents varied in all samples.

Keywords: Fermentation, extrusion, corn-groundnut flour blend, proximate