Chemicals Contents in Non-alcoholic and Alcoholic Beverages Produced from Purple-fleshed and Orange-fleshed Sweet Potato Varieties

Abstract

Chemical compositions and anti-oxidative characteristics of non-fermented and fermented beverages and associated solid by-products produced from freeze-dried sweet potato roots were examined.  Freeze-dried roots of purple-fleshed variety Quandow had higher total phenolics (9.32 mg g^-1) and total flavonoids (1.54 mg g^-1) contents and greater antioxidant activity (60.05 mg g^-1) than orange-fleshed variety Tainung 66 (1.14, 0.43 and 20.77 mg g^-1 of total phenolics, total flavonoids and antioxidant activity, respectively).  Fermented and non-fermented beverages and solids produced from Quandow also had higher antioxidants contents and greater antioxidant activities than those produced from Tainung 66.  Thus, producing non-fermented or fermented beverages from purple-fleshed variety Quandow has commercial potential and this will increase its economic value.  The purple-fleshed variety Quandow also produced high carbohydrate or high protein solid by-products enriched with antioxidants during beverage processing, which may be used as dietary carbohydrate supplements (non-fermented solids) or high protein animal feed (fermented non-alcoholic solids).