Options
2006
Journal Article
Titel
Gamma irradiation of cowpea (Vigna unguiculata L. Walp) flours and pastes
Titel Supplements
Effects on functional, thermal and molecular properties of isolated proteins
Abstract
In a previous study irradiation of cowpea flours and pastes at medium (10 kGy) and high (50 kGy) doses resulted in significant changes in protein-related functional properties. To understand some of the effects of gamma irradiation on cowpea proteins in particular, we isolated proteins from cowpea flours (FPC) and pastes (PPC) treated with gamma irradiation at 2, 10, and 50 kGy and analyzed their functional, thermal and molecular properties. Nitrogen solubility index of both FPC and PPC decreased, whereas oil absorption and emulsion capacities increased significantly with increasing irradiation dose. Differential scanning calorimetry showed decreases in transition temperatures (Td) and enthalpies (H), indicating a progressive denaturation of cowpea proteins with increasing irradiation. Size exclusion HPLC revealed increases in protein molecular weights, probably due to protein-protein cross-linking with irradiation in a dose-dependent manner. Reducing SDS-PAGE of FPC an d PPC samples seems to suggest that the contribution of disulphide bonds to irradiation-induced cowpea protein-protein cross-linking is small.