The Research Of The Relationship Between The Main Chemical Materials Of Green Tea And The Colour Deterioration

Green tea infusion is vulnerable to deterioration for light, temperature, humidity and oxygen which reduce the quality of green tea beverage.The relationship between the main chemical materials of green tea and the colour deterioration were illustrated by the SPSS software. A series of components missing and components gathering tea infusion were obtained by removed or added the separated colour rendering materials that have different distribution of the polarity. A series of tea infusion which lack of catechins were made by adding different concentration of PVPP which can absorb polyphenols. The materials related to the deterioration of green tea infusion colour were further studied. The main conclusions obtained as follows:1. The Pearson correlation analysis between chromatic aberration and the changes of main chemical compositions such as amino acid, total sugar, caffeine,catechin and flavonols of roasted green tea, Guapian, Huangya, Maofeng, Longjing were studied at40℃for12days by the SPSS software. The results showed that catechin and single glycoside of flavonols are most related to the deterioration of green tea infusion colour.2.The tea infusion was extracted by ethyl acetate and n-butyl alcohol to prepare the catechins-lacking tea infusion, the flavonol-lacking tea infusion, the catechins and flavonols-lacking tea infusion. The ethyl acetate phase which gathered catechins and the n-butyl alcohol phase which gathered flavonol were mixed to the tea infusion to prepared the catechins-gathering and flavonols-gathering tea infusions. The changes of tea infusion colour, the content of catechins and flavonol were observed during the high temperature ageing process, The results showed that The flavonol was the main colour material in tea infusion.The flavonol change intensive in the storage when the tea infusion lack catechins; The changes of flavonol were little than CK when the tea infusion gathered flavonol.The interaction of catechin and flavonol (especially the single glycoside) resulted in the deterioration of green tea infusion colour.3.The influence of green tea infusion associated with catechin and flavonol compounds were researched by adding different concentration of PVPP.The result showed that PVPP could adsorb not only flavonols but also catechins. The adsorbability to flavonoides was as follows:catechins＞flavonols,esters-catechins＞non-galloylated catechins,flavonol single glycoside＞flavonol diglucoside＞flavonol triglucoside.The color declined when added high concentration PVPP(more than1.0%). The changes of colour were not obvious in the high temperature ageing process subsequent. The chrominance of tea infusion declined slightly and the deterioration of colour intensified when added low concentration PVPP(less than1.0%) during high temperature ageing process. The decrease degree was as follows:Myricetin＞Quercetin＞Kaempferol; flavonol single glycoside＞flavonol diglucoside＞flavonol triglucoside.4EGCG and myricetin were prepared with different mole ratio for high temperature ageing reaction. The results showed that the colour was effected by the interactions of catechin and myricetin.