Effect of Bioprocess on Nutritional Quality and Chemical Properties of Bambara Groundnut (Vigna Subterranean (L) Verdc.) Flour

Abstract

The effect of bioprocess on the nutritional quality of bambara groundnut (Vigna subterranean (L) Verdc.) flour was studied and in-vitro protein digestibility of the raw (non-bioprocessed) flour was found to increase from 70.74 to 89.70% after fermentation while anti-nutritional factors was found to decrease from 4.72, 870.30, 1470.15, 1.85 and 8.40 mg/100gm to 2.08, 383.70, 1023.10, 0.55 and 3.30 mg/100 gm for tannin, polyphenol, phytate, oxalate and trypsin inhibition activity (TIA) respectively. The results was evident that the antinutrient concentration in bambara groundnut can be eliminated or reduced to tolerable level through the bioprocess of fermentation, thus increase protein digestibility. The crude protein content of raw bambara seeds was found to be 20.80% and slightly decreased after fermentation (19.70%). The results showed that bioprocess had no significant effect on protein content. Crude fat content significantly (p ˂ 0.05) increased from 6.80 to 8.79% after fermentation while carbohydrate content was found to decrease from 57.20 to 52.25% and this was attributed to the possible breakdown and utilization of the sugars by the fermenting organisms as a ready source of energy. Fiber content significantly (p ˃ 0.05) decreased from 6.60 to 3.98%; and this can also be attributed to the partial solubilization of cellulose and hemicellulosic type of material by microbial enzymes. Ash content was found to decrease from 3.45 to 3.18%; while dry matter slightly increased from 93.80 to 94.50%. Results obtained for gross energy showed that bioprocess significantly (p ˂ 0.05) increased the energy value to 425.10 kCal/100 gm. The calculated metabolizable energy values, which ranged between 368.10 and 425.10 kCal/100 gm showed that bambara groundnut have energy concentrations favorably comparable to cereals.

Keywords: Bioprocess, Bambara Groundnut, Anti-nutrients, Protein Digestibility