Sweet potatoes in Cameroon: Nutritional profile of leaves and their potential new use in local foods

Sweet potato (Ipomoea batatas) leaves especially the beta-carotene fortified varieties are rich in functional macro - and micronutrients such as dietary fibres, antioxidants and other micronutrients deficient in the predominantly starchy staples of most nutritionally vulnerable Africans. In this study, the nutrient content of young leaves and succulent green stems of local and exotic varieties were evaluated using standard analytical procedures. Dry matter content was lowest and highest in young leaves of the exotic Jewel 56638 and Mbouda local varieties, respectively. Young leaf crude protein content was 15.1% in the variety Jonathan and 27.1% in the Santchou local variety. Crude fibre and ash content were higher in the young leaves and stems of the exotic varieties. Leaf total carotenoid content varied significantly across varieties. The leaves were found to soften Gnetum africanum vegetable sauce giving it an acceptable appearance, texture, flavour and taste. About 80% of respondents on a survey were willing to readily use sweet potato leaves to substitute for Talinum triangulare (waterleaf) in the preparation of G. africanum sauce during periods of waterleaf scarcity. These leaves can therefore provide a nutritional base in Africa (especially Cameroonian) diets for the nutritionally vulnerable in rural and urban communities. Key words: Gnetum africanum, local and exotic varieties, nutrient content, sensory evaluation, sweet potato leaves.