Effect of Fermentation and Extrusion on the Nutrient and Anti-nutrient Composition of Soy Beans (Glycine max, L) and Acha (Digitaria exilis Stapf)

Aim: Effect of Fermentation and Extrusion on nutrient and anti-nutrient composition of Acha and deffated Soybeans.

Study Design: Four batches of Acha and defatted soy beans flour blends were varied at different ratio (100:0, 70:30 and 50:50). A batch was preconditioned and extruded. Another was fermented for 72 h. The third batch was fermented and extruded. The fourth batch was not fermented or extruded.

Place and Duration of Study: Department of Microbiology and Fishery Department Federal University of Akure, Ondo State between October 2015 and July 2016.

Methodology: Microbial analysis was carried out using potato dextrose agar, nutrient agar and De man Rogosa agar. pH, temperature and total titratable acidity analysis were carried out. Proximate, mineral composition, nutrient, anti-nutrient, of the blends was also carried out using standard methods.

Results: Fifteen organisms were isolated (Eight bacteria, five moulds and two yeasts) which include Lactococcus sp, Lactobacillus bulgaricus, Enterococcus, Staphylococcus aureus, Streptococcus thermophillus, Proteus mirabilis, Lactobacillus brevis, Pedicoccus sp, Rhizopous stonlonifer, Mucor mucedor, Aspergillus flavours, Penicillium freguentans, Fusarium merismoides, Saccharomyces cerevisiae and Candida utilis from all the batches of the sample after fermentation. The pH and titratable acidity (TTA) significantly varied during fermentation. The proximate composition showed an increase in nutritive value of the fermented extruded samples when compared with raw samples. There was significant increase in the mineral composition of the fermented samples when compared with the raw samples. Fermentation and extrution significantly reduced the anti-nutrient content of the samples. No significant difference was recorded in the fiber content of the raw flour blends and extrudates. This study revealed that fermentation and extrusion of acha and soybeans improved the nutritional quality of the samples and reduced the anti- nutrient content, also it can be used in weaning children in developing countries especially Nigeria.