Effects of Soaking Temperature and pH on Proximate and Mineral Composition of Bambara Nut (Vigna subterranea) Flour

Bambara nut (Vigna subterranea) is a drought tolerant legume containing a wide range of nutrients important in human nutrition. It is however relatively underutilized due to its hard-to-cook nature and anti-nutritional properties. Hence, this study investigated the influence of soaking temperature and pH on proximate and anti-nutritional properties of Bambara nut flour. A cream colored Bambara nut seeds were procured from Bodija Market, Ibadan, Oyo State. The seeds were cleaned, washed and soaked at different soaking temperatures (30 – 90 °C) and pH (3.0-10.0) for 12 h, dehulled, dried (60 °C for 48 h) and milled into flour. The soaking temperatures and pH were imputed into Response Surface Methodology (RSM) and thirteen runs were generated. The flour samples were analyzed for proximate and mineral composition. Data obtained were subjected to Analysis of Variance and means separated using New Duncan Multiple Range Test. Protein, crude fat, moisture content, carbohydrate, crude fiber and ash contents were in the ranges of 18.04-21.95, 7.92-8.48, 9.6- 11.6, 55.09-59.02, 1.0-1.8 and 1.91-3.01%, respectively. Sodium, calcium, magnesium, zinc, iron and potasium were 1.04- 2.43, 0.15-0.73, mg/100g, 4.62-5.83 mg/100g and 0.35-0.76, and 6.03-9.32 mg/100g respectively. This study has established the optimum soaking temperature (67.67 °C) and pH (3.1) and improve the bioavailability of its nutrients.