Abstract: The contents of total polyphenols total antioxidant activity, reducing power and hydroxyl radical scavenging capacity of 70% methanol extracts from raw, processed and preserved Carya cathayensis Sarg kernel were determined by Folin-Ciocalteu colorimetry and their total antioxidant activity, reducing power and hydroxyl radical scavenging capacity were measured. Total polyphenols contents were 1065.4, 319.78 mg/L and 204.4 mg/L in the extracts from raw, processed and preserved Carya cathayensis Sarg kernel, respectively. The total antioxidant activity and reducing power of the three extracts as evaluated with 2140 mg/L vitamin E as a reference standard decreased sequentially in the following order: raw Carya cathayensis Sarg kernel ＞ vitamin E ＞ processed Carya cathayensis Sarg kernel ＞ preserved Carya cathayensis Sarg kernel. In the case of hydroxyl radical scavenging rate, the order was vitamin E ＞ raw Carya cathayensis Sarg kernel ＞ processed Carya cathayensis Sarg kernel ＞ preserved Carya cathayensis Sarg kernel. Furthermore, total antioxidant activity, reducing power and hydroxyl radical scavenging rate had close correlation with the content of total polyphenols. Therefore, polyphenols are the important antioxidant components in Carya cathayensis Sarg kernel.

Key words: Carya cathayensis Sarg kernel, total polyphenols, antioxidation