Functional properties of cowpea (Vigna unguiculata L. Walp) flours and pastes as affected by γ-irradiation

Cowpea flours and pastes were irradiated at 2, 10 and 50 kGy and analysed for their functional properties. At low dose irradiation (2 kGy), most of the protein-related functional properties of cowpea flours and pastes were unaffected. At 10 and 50 kGy, however, all protein-related functional properties, except for water absorption capacity, were significantly (p ⩽ 0.05) affected. Nitrogen solubility index decreased significantly (p ⩽ 0.05), probably due to protein denaturation and/or aggregation, whereas oil absorption capacity increased significantly (p ⩽ 0.05), possibly due to exposure of previously buried non-polar protein sites. Starch-related functional properties, such as swelling and pasting properties, were decreased significantly (p ⩽ 0.05) in a dose-dependent manner, most likely due to starch degradation.