Cream Formation And Main Chemical Components Of Green Tea Infusions Processed From Different Parts Of New Shoots

摘要

The formation of green tea cream and its chemical components were investigated. The green tea infusions were processed from different parts of new shoots: the bud and the first leaf, the second leaf and its implicative stem, the third leaf and its implicative stem, and the fourth leaf and its implicative stem, which were named as first part, second part, third part and fourth part, respectively. The results showed that the formation of tea cream and its settlement slowed down gradually from the first part to the fourth part, and that the amount of tea cream also decreased accordingly. The amount of tea cream was influenced remarkably by the chemical components in the green tea infusion. The main components of green tea cream were polyphenols (29.86 -78.66%), total sugar (14.47-27.62%) and caffeine (2.35-10.43%). Catechins (12.8-42.5%) were the main components of polyphenols which participated in tea cream formation. The main components in the catechins were found to be (-)-epigallocatechin (EGC), (-)-epigal-locatechin gallate (ECCG), (-)-epicatechin (EC) and (-)-epicatechin gallate (ECG). Seven minerals were found in the tea cream, including Ca~(2+), K~(+), Mg~(2+), Mn~(2+), Na~(2+), Zn~(2+) and Ni~(2+).