Comparative Analysis of Sensory Evaluation Methods for Qingzhuan Tea

To propose a sensory evaluation method suitable for Qingzhuan tea, a representative Qingzhuan tea produced in Hubei was soak or spray boiled in order to analyze the effects of different boiling conditions on the sensory quality and the leaching rate of major chemical components of Qingzhuan tea. The sensory quality and chemical components of the tea infusions were compared with those of tea infusion obtained by the brewing method specified in the Chinese national standard. The results showed that the sensory quality of the boiled tea infusion was significantly better than that of the brewed tea infusion; the leaching rates of major quality components such as water extract, tea polyphenols, amino acids, soluble sugars and tea pigments were much higher in the former than in the latter. From the perspectives of sensory quality and the leaching rate of major quality components, tea infusion prepared by boiling for 2 min with a tea/water ratio of 1:80 and then standing for 2–4 min tasted moderate and had good internal quality. Further correlation analysis showed high correlation coefficients between the leaching rates of soluble sugars, theabrownine and water extract and taste quality. The results of this study provide a reference for the objective evaluation of the sensory quality of Qingzhuan tea and other types of compressed tea

Characterization of Roasting Time on Sensory Quality, Color, Taste, and Nonvolatile Compounds of Yuan An Yellow Tea

Roasting is crucial for producing Yuan An yellow tea (YAYT) as it substantially affects sensory quality. However, the effect of roasting time on YAYT flavor quality is not clear. To investigate the effect of roasting time on the sensory qualities, chemical components, odor profiles, and metabolic profile of YAYTs produced with 13 min roasting, 16 min roasting, 19 min roasting, 22 min roasting, and 25 min roasting were determined. The YAYTs roasted for 22 min got higher sensory scores and better chemical qualities, such as the content of gallocatechin (GC), gallocatechin gallate (GCG), free amino acids, solutable sugar, meanwhile the lightness decreased, the hue of tea brew color (b) increased, which meant the tea brew got darker and yellower. YAYTs roasted for 22 min also increased the contents of key odorants, such as benzaldehyde, nonanal, β-cyclocitral, linalool, nerol, α-cedrol, β-ionone, limonene, 2-methylfuran, indole, and longiborneol. Moreover, non-targeted metabolomics identified up to 14 differentially expressed metabolites through pair-wise comparisons, such as flavonoids, phenolic acids, sucrose, and critical metabolites, which were the main components corresponding to YAYT roasted for 22 min. In summary, the current results provide scientific guidance for the production of high quality YAYT