Effect of γ‐Irradiation on Cooking, Functional and Pasting Properties of Bambara Groundnut (Vigna subterranea [L.] Verdc.) Cultivars

Abstract

AbstractThe effect of γ‐irradiation dose (2, 4, 6, 8 and 10 kGy) on cooking, functional and pasting properties of four bambara groundnut cultivars (TvSu 315, TvSu 571, TvSu 760 and white) was investigated. Generally, sphericity, volume, surface area and aspect ratio of bambara groundnut seed increased significantly (P < 0.05) with increased γ‐irradiation dose and cooking time. Also, volume and surface area of seeds of TvSu 315 and white cultivars increased with increasing cooking time, while sphericity and aspect ratio showed mixed effect. At lower doses, increased γ‐irradiation resulted in decreased cooking time, elongation ratio and water uptake ratio of the seeds in all cultivars. However at higher doses, cooking time increased, while increase in γ‐irradiation showed little effect on seed elongation and water uptake ratio in all cultivars. Generally, water absorption capacity of flours increased significantly (P < 0.05) with increased γ‐irradiation dose in all cultivars, while oil absorption capacity increased until the 4 kGy and then declined. Foaming capacity, foam stability and swelling capacity of flours did not show dose‐dependent increase in all cultivars. Peak, trough, final and setback viscosities of flours decreased significantly (P < 0.05) with increased γ‐irradiation dose, while breakdown viscosity and pasting temperature did not show dose‐dependent increase.Practical ApplicationBambara groundnut is underutilized because of constraints like hard‐to‐cook phenomenon, strong beany flavor, presence of antinutrient and poor dehulling and milling characteristics. In many developing countries, the grain legume is stored as dry seeds. However, the seeds are very susceptible to insect infestation, which may start from the field, and vast qualities of seeds are lost annually as a result of insect attacks. Infestation of bambara groundnut seeds by Callosobruchus maculatus causes qualitative and quantitative losses and wastage. Also, the seeds are unsafe for immediate consumption due to the fact that fumigation chemicals are perceived to be carcinogenic. Therefore, γ‐irradiation was proposed as a viable alternative to the use of chemicals for pest control. Consequently, it is important to determine the effect of γ‐irradiation on cooking, functional, pasting and cooking properties of bambara groundnut seeds.