Journal of Taiwan Agricultural Research

Author:Tsung-Yen Wu, Hsin-Chen Lee, Tsai-Hsin Chiu, and Shwu-Jene Tsai

Abstract:

    A study was conducted to compare physicochemical properties and antioxidant activities of 13 varieties sweet potato (Ipomoea batatas) grown in Taiwan, including nine Tainung varieties (No. 57, No. 64, No. 66, No. 68, No. 69, No. 70, No. 71, No. 72, and No. 73) and four others (Taoyuan No. 1, Satsumahikari, Chingshey purple, and Ayamurasaki).  Hot water extracts from root tissues of each variety were used to determine total phenolic content, total anthocyanin content, DPPH (1,1-diphenyl-2-pricrylhydrazyl) and ORAC (oxygen radical absorbance capacity).  Results showed that total phenolic contents in Ayamurasaki (500.99 mg/100 g gallic acid, dry weight) and Chingshey purple (454.67 mg/100 g gallic acid; dw) were significantly (p < 0.05) higher than other varieties.  The DPPH scavenging ability was the highest in Chingshry purple (26.15 ± 1.84 μmol/ g Trolox equivalents; dw), followed by Ayamurasaki (21.90 ± 1.28 μmol/g Trolox equivalents; dw).  The values of ORAC in Ayamurasaki (129.42 ± 0.44 μmol/g Trolox equivalents; dw) and Chingshey purple (112.03 ± 0.86 μmol/g Trolox equivalents; dw) were higher than other eleven sweet potato varieties tested.  This study reveals that Chingshey purple and Ayamurasaki are two of the sweet potato varieties with potential for functional-food industry because of the high total phenolic contents, total anthocyanin contents, and antioxidant activities.

Key words:Sweet potato, Ipomoea batatas, Antioxidant activity, Hot water extraction

Download: PDF Links