Study Of Quality Change And Species Diversities In Puer Tea During Different Storage Time

Pu'er tea is fermented tea and is divided into raw and cooked pu'er, it's an unique kind of Chinese tea. The good pu'er has the double function of drinking and collection. The tea in the garden, the tea from cultivable wild old trees, the tea from wild old trees that sun-cured and formed (raw pu'er) were first used in this study, and the changes in quality characteristics by storage time and the difference of three kinds of tea has been investigated. The study provides data for medicinal value of tea form wild old trees and wants to further enhance the status of pu'er tea. Form this study, the tea from wild old trees can be protected effectively and used rationally; the consumer groups like the collection of pu'er tea can be discerning and scientific and evaluate pu'er tea objectively.The tea in the garden, the tea from cultivable wild old trees, the tea from wild old trees(raw pu'er) were stored for 1-6 years at the ventilated and clean space, and the average annual temperature was 21～22℃, the Aw was 70%. This three kinds of tea occurred slowly aging under the functions of temperature, light and Aw.The color of dry samples became micro-black-brown from micro-black-green, and the flavour became soft old flavor from sunlight flavor. The relative molecular mass of iridoid became less, and the relative molecular mass of esters, aromatic hydrocarbons and benzoquinones became more, and the taste became rich and pure from acerb, and the color of tea soup became light brown from light yellow, a* went up and b* went down. Water extract decreased at first and then increased and decreased again finally, and the total water extract decreased for 3.08%. The content of flavanoid increased by 6.40%, and in five years the content of tea polyphenols decreased while the content increased at the six year, and the content of caffeine decreased by 2.63%. The content of soluble sugar had little change, and the content of free amino acids and theaflavin decreased by 1.04% and 0.012%, respectively. Thearubigins decreased at first and then increased, and the total thearubigins increased by 0.309%, and the content of theabrownine increased for 0.762%.The color of dry samples became micro-brown from light-black-green, and the color of tea soup became red-yellow from light yellow, a* went up and b* went down. The content of theaflavin decreased, the content of thearubigins and theabrownine increased. The flavour became soft from sunlight and region flavor. The relative molecular mass of iridoid became less, and the relative molecular mass of alcohols, aldehydes, benzoquinones and esters became more. The taste became sweet and rich and gliding from acerb. Water extract increased for 7.45%. In firsr four years the content of tea polyphenols decreased while the content increased at the next two year, and the content of caffeine and free amino acids decreased by 2.63% and 1.04%, respectively. The color of dry samples became micro-brown from micro-black-green, and the color of tea soup became light-brown-yellow from yellow and green, a* went up and b* went down. The content of theaflavin remained unchanged, the content of thearubigins and theabrownine increased. The flavour became soft from sunlight and region flavor(like fleur). The relative molecular mass of iridoid became more, and the relative molecular mass of alcohols decreased first and then increased, the relative molecular mass of aldehydes and aromatic hydrocarbons became more first and then less. The taste became sweet and gliding from acerb. Water extract and flavanoid increased at first and then decreased and increased again finally, and increased by 1.04% and 0.012%, respectively. The content of tea polyphenols, caffeine and free amino acids decreased by 3.84%,1.32% and 0.7% respectively. The content of soluble sugar increased by 1.4%.The control sample was the raw pu'er collected in 2009, and the flavor of all samples was sunlight flavor. The quality characteristics of all samples were different because they growed at different places. The flavor of the tea from cultivable wild old trees and the tea from wild old trees were region flavor,while the tea in the garden was like fleur. The branch of the tea in the garden were sturdy and slender, and the branch of the tea from cultivable wild old trees were sturdy and strong, while the branch of the tea from wild old trees were sturdy and strong and heavy. The sequence of L*, a*, b* of different dry samples were:the tea in the garden> the tea from cultivable wild old trees> the tea from wild old trees. The sequence of L*, a*, b* of different tea soup were:the tea from wild old trees> the tea in the garden> the tea from cultivable wild old trees.The high-low order of the content of tea polyphenols and caffeine was the tea from cultivable wild old trees, the tea in the garden and the tea from wild old trees. The content of soluble sugar of three kind of tea were basically same; the tea from wild old trees had the highest content of free amino acids, and the other tea were basically the same. The tea from cultivable wild old trees had the highest content of catechin, and then was the tea in the garden, the least was the tea from wild old trees. The high-low order of the relative molecular mass of iridoid was the tea in the garden, the tea from cultivable wild old trees and the tea from wild old trees. The relative molecular mass of esters of the tea from wild old trees was higher than the tea in the garden and the tea from cultivable wild old trees obviously. The relative molecular mass of aldehydes and alkanes of the tea from wild old trees was higher than the tea in the garden and the tea from cultivable wild old trees. The relative molecular mass of aromatic hydrocarbons of the tea from cultivable wild old trees was higher than the tea in the garden and the tea from wild old trees.