Abstract

Agriculture in Africa currently stands at the crossroads of persistent food shortages compounded by food losses and climate change threats. Communities in several African countries are battling food security, as many are encountering huge number of food losses therefore the need for preservation cannot be emphasized. The objective of this study was to determine the effect of time-based oven-drying on proximate chemical composition of cowpea (Vigna unguiculata (L.) Walp.) leaves. A study was conducted at Limpopo Agro-Food Technology Station laboratory with a constant oven-drying temperature of 52°C. Two separate experiments were conducted for raw and cooked cowpea leaves with four treatments viz., 0 (sun-dried), 24, 48 and 72 h of oven-drying arranged in a randomized complete block design with five replications. Relative to control (sun-drying), 72 h ovendrying period significantly decreased protein, moisture, ash, fibre and carbohydrate by 10, 29, 18, 0.5 and 7% respectively. In contrast, relative to control, 72 h oven-drying period significantly increased energy and fat by 3 and 46%, respectively. Similarly, relative to control, 72 h oven-drying period decreased protein, moisture, energy, ash, fat, fibre and carbohydrate by 8, 14, 1, 13, 19, 0.4 and 10%, respectively. Seventy-two hours of ovendrying period was observed to have detrimental effect on the proximate composition of both raw and cooked cowpea leaves, therefore, oven-drying period should be limited to 24 h during oven-drying of leafy vegetables.