Application of chemical composition and infusion colour difference analysis to quality estimation of jasmine-scented tea

Infusion chemical composition, colour difference indicators and volatile constituents of seventeen jasmine-scented tea samples and their correlation with sensory total quality score given by tea-tasting panel were studied by techniques of HPLC, colour difference metre and gas chromatograph. Spearman's linear correlation analysis showed that concentration of nitrogen, caffeine, catechin, epicatechin, catechin gallate, total catechins, terpineol, nerol and infusion light-black indicator Delta L, yellow-blue indicator Delta b, total colour difference indicator Delta E were significantly correlated with sensory total quality score, respectively. Regression of the total quality score upon twelve components extracted from thirty-six tested indicators by principal component analysis could properly estimate total quality score of two jasmine-scented tea samples which were not included in the seventeen samples used to construct the regression model.