Physical, proximate, functional and pasting properties of flour produced from gamma irradiated cowpea (Vigna unguiculata, L. Walp)

Cowpeas are leguminous seeds widely produced and consumed in most developing countries of sub Saharan Africa. The aim of this study was to determine the physical, proximate, functional and pasting properties of flour obtained from gamma irradiated cowpea. Four cowpea cultivars were irradiated with gamma radiation at dose levels of 0.25, 0.5, 0.75, 1.0 and 1.5 kGy with the unirradiated cultivars serving as controls. The samples were hammer milled, sieved and stored at 4 °C for analysis. Physical, proximate, functional, pasting properties were determined using appropriate methods. In general, the irradiation dose applied to cowpea for insect control did not significantly affect the physical and proximate properties of the flour. However, significant increase (p<0.05) was achieved in paste bulk density, water and oil absorption capacities, foam capacities and least gelation concentrations of flour in general, which may be attributed to the irradiation. The radiation reduced the swelling power and water solubility index significantly. The peak temperature, peak viscosity and setback viscosity of the pastes were significantly (p<0.05) reduced while breakdown viscosity was significantly (p<0.05) increased by the radiation. It was established that the doses used on cowpea affected both the functional and pasting properties of the flour.

► We investigated the effects of gamma irradiation of cowpea on quality characteristics of its resultant flour.
► Flour was prepared from four cowpea cultivars irradiated at 0, 0.25, 0.5, 0.75, 1.0 and 1.5 kGy.
► Proximate and physical properties of flour from irradiated cowpea were generally not affected by the radiation doses used.
► Functional properties of flour samples were affected by gamma irradiation of cowpea.
► Pasting parameters studied were also affected by the radiation at various radiation doses.