Analysis on Quality Indicators of Taste and Infusion Color and Discrimination of Famous and Superior Green Tea with Different Appearances in Fujian Province, PR China

Abstract

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.

A novel application of check‐all‐that‐apply with semi‐trained assessors for tea sensory characterization and preference: Using Longjing tea as a case study

“…The Longjing teas with scores above 90 were positively correlated with overall quality and five sensory factors based on QDA. The results were in agreement with previous studies, which reported that special‐grade green teas (total sensory scores ≥90) are characterized by super‐excellent appearance features, bright and green tea infusion, high and pleasant aroma, and umami taste, due to their rigorous harvest season, harvesting standard and delicate processing (Guo & Lai, 2016; Li et al, 2019). In a word, traditional QDA was an effective tool to distinguish tea overall quality grade; however, tea flavor characterization could not work.…”

Characterizing relationship between chemicals and in vitro bioactivities of teas made by six typical processing methods using a single Camellia sinensis cultivar, Meizhan

“…Meizhan is one of the most widely cultivated varieties in China, with rich aroma components and widely processing suitability [ 16 , 17 ]. Aim to disclose the impact of tea processing method on phytochemicals of tea and explore the potential health effect of various teas, meanwhile, minimize the influence of material differences.…”