Journal of Taiwan Agricultural Research

Author:Shwu-Jene Tsai*, Huey-Ing Liu and Hsing-Yi Huang

Abstract:

    The acridity of raw taro can be eliminated by appropriate cooking and food processing. Protein is known as a thermal-denaturing substance. Therefore, the potential effect of protein fractions of taro corms on acridity was evaluated and studied in this research. Five protein fractions were obtained by sequential extraction, including water-soluble, hot water-soluble, salt-soluble, alkali-soluble and alcohol-soluble protein fractions. The result showed a significant difference in acridity among taro cultivars. Taro cultivar with stronger acridity has a higher content of insoluble oxalate, but lower of fractioned proteins. The acridity of raw taro corms was correlated positively with the content of insoluble oxalate (r = 0.90, p < 0.05), and negatively with most of the fractioned protein contents (r = -0.89～-0.99, p < 0.05). Steaming of taro resulted in the significant loss of acridity as well as the decreases of water-soluble and total protein contents. However, steaming had little effect on the change of the insoluble oxalate contents. It might be concluded that the acridity of taro was not only caused by insoluble oxalate, but also in associated with some protein fractions of in taro. The thermal denaturation of proteins in taro might cause decline of acridity during cooking.

Key words:Taro, Acridity, Insoluble oxalate, Protein fractions

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