2010 Fiscal Year Final Research Report

Study on color formation of green tea liquor caused by complexation of pigments with the other components.

Research Project

Project/Area Number	21700747
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Eating habits, studies on eating habits
Research Institution	National Agricultural Research Organization
Principal Investigator	UJIHARA Tomomi 独立行政法人農業・食品産業技術総合研究機構, 野菜茶業研究所・野菜・茶の食味食感・安全性研究チーム, 主任研究員 (60355609)
Project Period (FY)	2009 – 2010
Keywords	食品 / 緑茶水色 / フラボノイド / 複合体形成 / カテキン / 金属イオン
Research Abstract	Copper, iron, and aluminium ions caused hyperchromic effect to monoglucosyl rutin aqueous solution. Catechins caused hypochromic effect to the solution, and the effect of gallate-type catechins was greater than that of non-gallate-type catechins. Catechins formed 1:1 complexes with the monoglucosyl rutin. Binding constants were larger in gallate-type catechins than in non-gallate-type catechins. These results suggest that the complexation between gallate-type catechins and monoglucosyl rutin are responsible for the color change of the monoglucosyl rutin solution. The color of the metal-monoglucosyl rutin mixture solution became paler by adding epigallocatechin gallate to the solution, nonetheless, the color was deeper than that of the monoglucosyl rutin solution added epigallocatechin gallate only.