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.