Reduction of catechin astringency by the complexation of gallate-type catechins with pectin.
The reductive effect of pectin on tea catechin astringency was investigated by using a taste sensor system and (1)H-NMR spectroscopy. The sensor analysis revealed that the astringency of gallate-type catechins (EGCg and ECg) was reduced by the addition of pectin, whereas that of non-gallate-type catechins (EGC and EC) hardly changed. Changes in the (1)H-NMR chemical shifts of the catechins and pectin in mixed solutions showed that the gallate-type catechins formed complexes with pectin more closely than the non-gallate-type catechins. These results demonstrate that complexation between the gallate-type catechins and pectin is a factor for reducing catechin astringency.
Hayashi
Nobuyuki
N
Department of Physiology and Quality Science, National Institute of Vegetable and Tea Science, 2769 Kanaya, Shimada, Shizuoka 428-8501, Japan. hayn@affrc.go.jp
Ujihara
Tomomi
T
Kohata
Katsunori
K
D015374:Biosensing Techniques; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D010368:Pectins / Q000737:chemistry*
D010368:Pectins; D002392:Catechin; C057580:gallocatechol