Research of effect and mechanism of infusion color of green tea by adding PVPP

The effect of catechins and flanonols compounds on green tea infusion color were investigated by adding different concentration of PVPP.As observed, the green tea infusion color was close to be colorless and the light color system was stable with adding high concentration of PVPP (>1.0%) , but the chroma values a and b of the green tea infusion color were slightly reduced with adding low concentration of PVPP (<0.5%) , which further increased the color deterioration during the green tea infusion storage.Based on these observation data, it was suggested that the PVPP could adsorb flavonols, which were color compounds, to attenuate the green tea infusion color.Further studies showed that the catechins' adsorbility was stronger than flavonols' and the adsorbilty of catechins was proved to be:ester catechins>non-ester catechins.While the adsorblity of flavonols was:single indicant>diglucoside>triglucoside.Additionally, the transform ability of flavonol-like compounds was proved to be:myricetin>quercetin>kaempferol in the absence of catechins during the green tea infusion storage, while flavonol triglucoside was more stable than monoglycoside.