Compared to traditional sensory quality evaluation, chemical components and color values in CIE-Lab space are looked as indicators to assess tea quality objectively. This study spectrophotometrically analyzed quality indicators of famous and superior green tea (FSGT) with three appearance types in the Fujian Province, PR China and applied chemometrics methods to discriminate them. By factor analysis, all indicators were classified into four factors, evaluating FSGT quality in (1) lightness, yellowness and saturation of infusion color and astringency and bitterness of taste; (2) umami and mellowness; (3) greenness; and (4) body. By the principal component (PC) analysis, three appearance types were separated from each other with the cumulative variance contribution rate of 88.35% for the first three PCs based on indicators of taste and 90.30% for the first two PCs based on indicators of infusion color, respectively. By Bayes discrimination analysis, three decision functions were established to effectively discriminate three appearance types of FSGT.
PRACTICAL APPLICATIONSFujian is one of the popular provinces producing green tea in China and has a long history of processing famous and superior green tea (FSGT), which have the best quality and are usually known for their distinctive appearances and flavors. FGST qualities among different appearances or within the same appearance originating from different areas or using different cultivars often have distinctive qualities and maybe have similar qualities. Traditionally, FGST qualities are appraised and discriminated by the sensory evaluation, which is subjective and difficult to describe qualities quantitatively. Chemometrics methods use chemical components as indicators, which are objective and achieve quantified qualities. Therefore, they could be used as advantageous complements or references for traditional sensory evaluation.