Effect of Some Thermal Processing Techniques on the Proximate, Mineral and Anti-Nutrient Compositions of Bambara Groundnut (Voandzeia subterranea, (L) Thour) Meal

Abstract

The effect of some thermal processing techniques on the nutritional potentials and anti-nutritient properties of  bambara groundnut were investigated. The results of the proximate composition showed significant differences (P < 0.05) in all the parameters tested except the ether extract. The crude protein (22.35%) and nitrogen free extract (55.83%) of the raw bambara groundnut (BG) were significantly (P<0.05) higher than all thermally treated BG values, but thermally treated BG were significantly (P<0.05) lower in crude fibre contents. The gross energy levels of the boiled BG (with or without potash) were significantly (P<0.05) higher than that of the raw and toasted BG. Result of the mineral composition shows that raw BG had the highest concentration of Mg(0.48%), P(0.58%) and Na(11.49%) followed by potash boiled bambara groundnut (Mg 0.41%, P 0.52% and Na 11.40%). The results indicated the presence of some anti-nutritional factors in the meals. Trypsin inhibitor, tannin and oxalate were significantly (P < 0.05) reduced in the thermally processed meals. The trypsin inhibitor (TU/mg), tannin (mg/100g) and oxalate (mg/100g ) of the raw BG were highest (28.60, 0.38 and 0.60 respectively) followed by the toasted BG(22.10, 0.14 and 0.38 respectively). From the results obtained, boiling bambara groundnut in potash solution produced meals with best nutritional values for livestock and reduced the anti-nutritient substances of the seeds.

Keywords:   Bambara groundnut, thermal, proximate, mineral, composition, anti-nutrient   substances.