Nutrient composition and functional properties: Suitability of flour of sweet potatoes (Ipomea batatas) for incorporation into food production

Abstract

Sweet potatoes are effortlessly grown and high yielding food crop. However, these are considered as underutilized produce with limited incorporation into food industry. Hence the objectives of this study were to determine the nutrient composition and functional properties of twelve (12) sweet potato varieties available in Sri Lanka to study the potential to be incorporated into food production. The varieties analysed were Ama, Dhawala, Wariyapola White, Wariyapola Red, Shanthi, Hordi Malee, CARI 09, CARI 273, Ranabima, Gannoruwa White, Chithra and Makandura Purple. Determination of moisture, ash, crude protein, crude fat, dietary fiber (soluble/insoluble), carbohydrates and functional properties were by standard methods. Ash, crude fat and crude protein contents comprised less than 7% (dry matter; DM) with total carbohydrate content varying between 49-80% DM in studied sweet potatoes. Total dietary fiber comprises approximately 8.5% (DM) with the highest proportion being insoluble dietary fiber. Functional properties resulted a swelling capacity of 15-27 mL with high oil absorption capacity (120-220%), emulsion activity (42-48%) and stability (above 35%), and bulking density (0.62-0.95 g/cc) with least gelation concentration of 18-30%. The results prove the ability of the studied sweet potato flours to be incorporated in composite flour mixtures and novel food products.