Effect of Gamma Irradiation on Nutritional Quality and Shelf Life of Cowpea (Vigna unguiculata) Produced in Benue State Nigeria

Abstract

Cowpea plays an important role in the lives of millions of people in the developing world, providing a major source of dietary protein that nutritionally complements low-protein cereal and tuber crops.  However, during storage, cowpea is attacked by a number of biological agents, which result in losses in the quality and quantity of stored seeds. This research investigated the application of Cobalt-60 gamma irradiation on the proximate composition and shelf life of locally produced cowpea seeds in Benue State, Nigeria. Cowpea seeds were irradiated at doses of 200 Gy, 300 Gy, 400 Gy, and 500 Gy and stored for four months. Proximate analysis revealed no significant difference (p ≥ 0.01) in protein, fat, ash, crude fibre, and carbohydrate content between irradiated cowpea seeds and the control. However, a significant difference (p ≤ 0.01) was observed in moisture content across all doses. After four months of storage, weight loss analysis indicated significant differences between irradiated and non-irradiated seeds of cowpea. Control samples experienced greater damage from insect infestation, resulting in the highest percentage of weight loss compared to irradiated samples. Notably, 500 Gy exhibited the least weight loss among irradiated samples, highlighting a dose-dependent effect of gamma irradiation on weight loss and its potential impact on shelf life. Irradiation doses, of 500 Gy for cowpea, can effectively preserve the nutritional components and extend the shelf life of cowpea, offering an alternative to chemical preservation methods.