by WTN Staff

A study conducted by a team of Korean academics has indicated that shading green tea plants during cultivation makes a significant difference in the chemical composition of the tea.

Researchers from Kon-Kuk University in Seoul, the Food Research Institute in Gyeonggi-do and Korea University in Seoul contributed equally to the study, which appeared in a November issue of the Journal of Agricultural and Food Chemistry, a peer-reviewed scientific journal.

The team based its work on studies that have set out to find and measure differences between green tea and shade-cultured green tea (tencha). The researchers employed an analytical method that had not been used before. Called metabolomics, the method, in lay terms, is a way of looking at the chemical fingerprints left behind by metabolites as cells grow and change. Metabolites are small molecules produced during the process of metabolism.

While complicated, the results did lead to some conclusions about the differences between green tea and shade-grown green tea. For instance, the study's summary stated that "green teas have more catechins and sugars than tencha, whereas tencha samples have more flavonoid derivatives than green teas... The levels of epicatechin, epigallocatechin, galloylquinic, succinic acid and fructose found in the green tea samples were significantly higher than those found in the tencha samples. Since most of the catechin compounds have antioxidant capability, this could be one of the reasons why the tencha samples showed less antioxidant activity."

On the other hand, the study indicated that shade production offers the possibility of producing tea with high umami and less astringency than regular green tea.

The researchers further noted that the study suggests metabolomics is an effective approach for studying the chemical composition of teas produced by different cultivation methods.