Inhibitory activity of traditional post-fermented tea "Goishi-tea" on AGEs formation and its involved components

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K02319
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 08030:Family and consumer sciences, and culture and living-related
• Research Institution: Kochi University
• Principal Investigator: Shimamura Tomoko 高知大学, 教育研究部総合科学系生命環境医学部門, 教授 (50350179)
• Co-Investigator(Kenkyū-buntansha): 柏木 丈拡 高知大学, 教育研究部総合科学系生命環境医学部門, 教授 (60363256)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 後発酵茶 / 碁石茶 / 抗糖化活性 / AGEs / カテキン

Outline of Final Research Achievements

Various biological functions have been reported for Goishi-tea, a post-fermented tea produced through a two-step fermentation process. However, knowledge on the functionally active components has been scarce. In this study, we attempted to elucidate the functional components of Goishi tea by using its anti-glycation activity as an indicator. As a result, it was found that Goishi tea has high anti-glycation activity. In addition, the contribution of catechin monomers and their degradation products to the activity was low, suggesting the presence of unknown involved components. Finally, we concluded that proanthocyanidins (PAs), catechin polymers, are the functional components involved in the activity of Goishi tea. PAs have also been reported to contribute to the development of bitter and astringent tastes in Goishi tea. Thus, it is suggested that PAs in Goishi tea plays an important role in both functionality and taste.

Free Research Field

食品化学

Academic Significance and Societal Importance of the Research Achievements

碁石茶は世界に類を見ない製法で製造される後発酵茶であり、その生体調節機能や機能性関与成分に関する科学的知見の蓄積は、碁石茶の高付加価値化だけでなく、“後発酵茶”という長い歴史を持つ文化の解明にも繋がる重要な事柄である。また、本研究の成果で機能性関与成分であることが示唆されたカテキン重合物は微生物発酵の過程で生成している可能性が高く、二段階発酵の製法が受け継がれてきた意味を紐解く鍵になり得る。