Effect of Pretreatments for Retaining Total Carotenoids in Dried and Stored Orange-Fleshed-Sweet Potato Chips

Various dipping pretreatments have been investigated for orange-fleshed sweet potato (OFSP) to retain carotenoids after drying and subsequent storage. Effects of blanching, sodium metabisulfite (0.5 or 1%), acids (ascorbic acid [1%] or citric acid [0.5%]) or salt (1%), either singly or as mixtures, were tested on dried OFSP chips that were stored for up to 6 months in ambient conditions. Overall, there was a positive effect of dipping on total carotenoid content after drying compared with control (P < 0.05). A slight improvement in carotenoid content was observed during the first month of storage with ascorbic acid, sodium metabisulfite, and mixtures of sodium metabisulfite and citric acid, or ascorbic acid and salt pretreatments, but these higher levels were not maintained over longer storage periods (4–6 months). The general lack of improvement was believed to result from the leaching and degradation of the chemicals during storage.