Science Links Japan | Study on Antioxidative Assay Using Photon Detection Part II. Relationship Between Antioxidative Activity Estimated by XYZ-dish Method and Catechin Concentration in Commercially Available Tea Drinks.

Study on Antioxidative Assay Using Photon Detection Part II. Relationship Between Antioxidative Activity Estimated by XYZ-dish Method and Catechin Concentration in Commercially Available Tea Drinks.

Accession number;00A0301132

Title;Study on Antioxidative Assay Using Photon Detection Part II. Relationship Between Antioxidative Activity Estimated by XYZ-dish Method and Catechin Concentration in Commercially Available Tea Drinks.

Author; IWAI KUNIHISA (Aomori Advanced Ind. Technol. Center) SATO MARIMO (Aomori Advanced Ind. Technol. Center) MATSUE HAJIME (Aomori Advanced Ind. Technol. Center)

Journal Title;Journal of the Japanese Society for Food Science and Technology

Journal Code:F0895A

ISSN:1341-027X

VOL.47;NO.2;PAGE.120-129(2000)

Figure&Table&Reference;FIG.6, REF.22

Pub. Country;Japan

Language;Japanese

Abstract;A relationship between antioxidative activity and catechin concentration was investigated for estimating antioxidative potency of commercially available tea drinks by using the XYZ-dish method. Antioxidative activity of canned drinks determined by the XYZ-dish method increased in the following order: other teas<oolong teas<green teas. The antioxidative activity of tea infusions extracted from green tea leaves was markedly stronger than that of canned tea drinks. Epigallocatechin gallate(EGCg), gallocatechin gallate and epigallocatechin(EGC) were found to have stronger antioxidative activities. It was suggested that the presence a hydroxyl group at 5'-position of B ring and the total number of aromatic hydroxyl groups contributed to the increase in activity. The concentration of catechin compounds in tea drinks showed different levels among the tea samples examined, particularly it was markedly higher in the tea infusions than in canned tea drinks. High contents of EGCg and EGC were detected in most of the tea drinks with stronger antioxidative activities, suggesting that the two catechins mainly affected the antioxidative activity of tea drinks. Furthermore, it was confirmed that the antioxidative activity was dependent on the catechin concentration, because a significant high correlation was found between the activities and the total concentration of eight catechins in the tea drinks. These results demonstrated that the XYZ-dish method was useful as an antioxidative assay of tea drinks containing polyphenolic antioxidant activity. (author abst.)

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