Study of Potential Effect and Health Benefits of Soaking Time on the Nutritional Composition and Some Anti-Nutrient Factors in Cowpea (Vigna unguiculata)

Abstract

The study of the potential effect and health benefits of water soaking time on the nutritional composition and some anti-nutrient factors (phytate, hydrocyanic acid, oxalate, saponin, flavonoid, alkaloid and tannins) in cowpea (Vigna unguiculata) was determined. Cowpea seeds were divided into three batches of 100g each. Two batches were soaked in clean tap water for one and two hours respectively.  The result revealed that the moisture contents of cowpeas increased with soaking time from (7.87%  at 0hour, 50.52% at 1 hour to 53.35% at 2 hours); fat from (1.45% at 0hour, 1.57 at 1 hour to 2.25% at 2 hours), also increasing with soaking time were carbohydrate and caloric contents of the cowpea from (70.25% at 0hour, 70.96% at 1hour to 74.00% at 2hours) and (383.67% at 0hour, 384.76% at 1hour to 390. 43 at 2hours%) respectively. It was also observed that soaking of cowpea for one and two hours independently decreased the protein, fibre & ash contents of the cowpea ranging from (22.40% to 18.55% protein), (2.36% to 2.08% fibre) and (3.5398% to 3.1204% ash). All the anti-nutrients studied recorded slight reductions except oxalates and alkaloids which were significantly (P<0.05) reduced with soaking time. This indicates that longer water soaking time is an effective way of lowering toxic substances in legume-based foods and enhancing nutrient bioavailability.