EFFECT OF DOMESTIC PROCESSING (COOKING AND ROASTING) ON ANTIOXIDANT POTENTIAL OF BAMBARA GROUNDNUT EXTRACT (VIGNA SUBTERANEA L.VERDC.)
Bambara groundnut is a crop that is considered to be indigenous to the African continent. Bambara groundnut is grown mainly for its edible and nutritionally rich seeds. The aim of this study was to explore the effect of domestic processing on the antioxidant potential of Bambara groundnut. Two landraces from Yobe and Kano states, Nigeria were screened in raw and processed forms. The effect of cooking and roasting on antioxidant potentials and phenolic phytochemicals of the two landraces were assessed. The study employed in vitro antioxidant assays 1-1-diphenyl-2-picrylhydrazyl (DPPH) and Ferric reducing antioxidant power (FRAP) to screen for change in antioxidant property and Folin Ciocalteu assay to screen for change in phenolic content respectively. Result were presented in mean ± SD. The Yobe landrace exhibited the highest DPPH free radical scavenging activity with 56.58% ± 0.05 for the roasted Bambara compared to 40.57 % ± 0.08 of the Kano landrace. Again the ferric reducing antioxidant power (FRAP) was higher in the roasted Yobe landrace of Bambara groundnut with 9.40 mmol Fe2+/100g ± 0.40 compared to 8.34 mmol Fe2+/100g ± 0.36 in the roasted Kano Bambara groundnut. The total phenolic content were 34.22 as GAE ± 0.111 and 28.19 ± 0.25 as GAE in the roasted Yobe and roasted Kano Bambara groundnut respectively. The effect of domestic processing on the antioxidant activity and total phenolic content follows the same trend and the increase was revealed in the following order: RBY>RBK>CBY>CBK>CSY>CSK.