Carotenoid contents in fresh, dried and processed sweetpotato products

Abstract

In order to understand the effects of drying and processing sweetpotato storage roots into traditional baked food products on their pro-vitamin A contents. Total carotenoids and fJ-carotene were colorimetrically determined. Fresh and cooked storage roots. dried and stored chips. and sweet potato processed procucts were used. Flesh colors of the storage roots were white, yellow, cream, orange, and purple. Total carotenoids ranged from trace to above 9 rng fi-( arotene equiv.llOO g of fresh storage root. Storage roots of high carotcnoid cor tent cultivars had consistently orange flesh: those with low to very low carotenoid contents were yellow or white. Hunter "b" values were high and consistent for noms from orange- and cream-fleshed root cultivars, which could easily be used to predict total carotenoid and f)-carotene contents. Drying sweetpotato storage roots at 65°C for 12h reduced total carotenoid contents by 30%. Storing dried chips in ambient conditions for II months induced a 10% loss. Incorporation of flour made from orange-fleshed sweetpotato roots into buns, chapatis and mandazis enriched the products in total carotenoids from n.l mg to 2.3 mg fJ-carotene equivalents per 100 g product. Results of this study suggest that increased consumption of orange-neshed sweet potatoes in either fresh or processed form can contribute in alleviating dietary deficiency of vitamin A.