本研究主要是探討以不同烹調方法 (蒸煮與烘烤)，對三種品種甘藷不同部位 (甘藷肉、皮和帶皮甘藷) 之 抗氧化活性及抗氧化成分之影響。三種不同品種甘藷，分別為黃皮黃肉的台農57號 (TN57)、紅皮紅肉的台農 66號 (TN66) 和紫皮紫肉的台農73號 (TN73)。將烹調後之樣品 (甘藷、甘藷皮和帶皮甘藷) 經冷凍乾燥及磨粉 後以80%甲醇萃取。三種品種 (TN57、TN66及TN73) 之甘藷皆以蒸煮方法處理的帶皮甘藷產率最高，分別為 49.82%、51.57%和45.57%。TN73之蒸煮甘藷皮 (SP) 的總酚、類黃酮及總花青素含量最高，分別為18.97 GAE mg/g d. m.、16.98 CE mg/g d. m.以及1.99 TA mg/g d. m.。不同部位樣品之抗氧化成分含量依序為甘藷皮＞帶皮 甘藷＞甘藷肉。另外，不同烹調方法之抗氧化成分含量依序為蒸煮＞烘烤＞未處理。TN73 SP萃取物之抗氧 化活性為所有樣品中最高，其DPPH自由基清除能力、還原力及總抗氧化能力分別為81.17%、OD700 nm = 1.60及 18.03%。TN73 SP萃取物之主要酚類化合物為綠原酸、阿魏酸及兒茶素。甘藷皮中富含抗氧化成分，因此本研 究認為甘藷應連皮一起食用，且以蒸煮的方法烹調可提高其抗氧化活性與抗氧化成分含量。

The purpose of this study was to investigate the effect on antioxidative activity and antioxidative components of different parts (including flesh, peel and whole root) of three sweet potato varieties with different cooking methods (including steaming and baking). Three sweet potato varieties were selected on the basis of their flesh and peel color. Tainung 57 (TN57) had yellow tuber flesh and peel, Tainung 66 (TN66) had red tuber flesh and peel, and Tainung 73 (TN73) had purple tuber flesh and peel. Cooked samples (including flesh, peel and whole root) were freeze-dried, ground to fine powder and then extracted with 80% methanol. Results showed that the steamed whole sweet potato of TN57, TN66, and TN73 had the highest extraction yield which was 49.82%, 51.57% and 45.57%, respectively. The steamed peel (SP) of TN73 had the highest total phenolics, flavonoids and anthocyanin content which was 18.97 GAE mg/g d. m., 16.98 CE mg/g d. m. and 1.99 TA mg/g d. m., respectively. The order of antioxidative components content of different parts of samples was peel > whole root > flesh. In addition, the order of antioxidative components content of different cooking methods was steaming > baking > raw. Specifically, the TN73 SP extract showed the highest antioxidative activity among all samples. The DPPH radical scavenging activity, reducing power and total antioxidant capacity (TEAC) of the TN73 SP extract was 81.17%, OD700 nm = 1.60 and 18.03%, respectively. The major phenolic compounds of the TN73 SP extracts were chlorogenic acid, ferulic acid and catechin. Sweet potato peels were rich in antioxidative components. Therefore, this study suggested that sweet potato should be consumed with skin still on it, and cooking by steaming could increase its antioxidative activity and the contents of the antioxidative components.