Effect of Cyclodextrins on the Thermal Epimerization of Tea Catechins

• OKUMURA Hisako

  Graduate School of Natural Science & Technology, Kanazawa University

• ICHITANI Masaki

  Central Research Institute, Ito En, Ltd.

• TAKIHARA Takanobu

  Central Research Institute, Ito En, Ltd.

• KUNIMOTO Ko-Ki

  Graduate School of Natural Science & Technology, Kanazawa University

Abstract

The epimerization reaction of tea catechins was investigated at pH 5.5 and 120 °C in the absence/presence of cyclodextrins (CDs). In the absence of CDs, a considerable quantity (∼20%) of products originating from reactions other than the epimerization (“other products”) was formed during the epimerization of gallated catechins. In the case of (-)-EGCg, addition of β-CD to the reaction solution reduced the quantity of these other products to just a few percent, but other CDs with different cavity sizes had little effect. Generally, the addition of β-CD increased the ratio of non-epi type catechins, that is, [non-epi type catechin] / ([epi type catechin]+[non-epi type catechin]). Molecular orbital (MO) calculations using the PM3 method suggested that non-epi type catechins are more thermodynamically stable than their epitype counterparts, moving the equilibrium position in favor of non-epi type catechins in the epimerization process.

Journal

• Food Science and Technology Research

  Food Science and Technology Research 14 (1), 83-88, 2008

  Japanese Society for Food Science and Technology

Keywords

• tea catechins
• thermal epimerization
• cyclodextrin
• epi type catechins
• non-epi type catechins

Details

• CRID: 1390282679432267520
• NII Article ID: 10021184719
• NII Book ID: AA11320122
• DOI: 10.3136/fstr.14.83
• ISSN: 18813984
• ISSN: 13446606
• Web Site: http://hdl.handle.net/2297/17261
• Text Lang: en
• Data Source:
  • JaLC
  • IRDB
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed