Variations in the carotenoid and anthocyanin contents of Korean cultural varieties and home-processed sweet potatoes

Abstract

The sweet potato is an important industrial crop and a source of food that contains useful dietary fiber and vitamins. Recently, orange- and purple-fleshed varieties have come under the spotlight due to their healthful components, carotenoids and anthocyanins, respectively. In this study, an HPLC-DAD method was applied to determine the carotenoid composition and content in nine Korean cultural varieties of sweet potato. Changes in carotenoid contents and composition were also observed during home-processing of an orange-fleshed cultivar with high carotenoid content (530 60 mu g/g of dry weight, DW as all-trans-beta-carotene). A loss of the carotenoids was observed for all of the home-processing methods examined; the baked or boiled or steamed sweet potatoes had higher amounts of all-trans-beta-carotene (246 +/- 34, 253 +/- 29 and 240 +/- 21 mu g/g DW, respectively) than pressure-cooked, sauteed and fried ones (194 +/- 21, 201 +/- 28 and 111 +/- 19 mu g/g DW, respectively). Interestingly, cis-isomer of the all-trans-beta-carotene, 13Z-beta-carotene was found in elevated amounts in all of the processed samples, particularly in baked, pressure-cooked and steamed sweet potatoes compared to control. Variations in anthocyanin content in the nine cultural varieties and home-processed sweet potatoes were also determined by an HPLC-DAD method. (C) 2015 Elsevier Inc. All rights reserved.