A Comprehensive Investigation of Macro-Composition and Volatile Compounds in Spring-Picked and Autumn-Picked White Tea

Abstract

The flavour of white tea can be influenced by the season in which the fresh leaves are picked. In this study, the sensory evaluation results indicated that spring-picked white tea (SPWT) was stronger than autumn-picked white tea (APWT) in terms of the taste of umami, smoothness, astringency, and thickness as well as the aromas of flower and fresh. To explore key factors of sensory differences, a combination of biochemical composition determination, widely targeted volatilomics (WTV) analysis, multivariate statistical analysis, and odour activity value (OAV) analysis was employed. The phytochemical analysis showed that the free amino acid, tea polyphenol, and caffeine contents of SPWTs were significantly higher than those of APWTs, which may explain the higher umami, smoothness, thickness, and astringency scores of SPWTs than those of APWTs. The sabinene, (2E, 4E)-2, 4-octadienal, (-)-cis-rose oxide, caramel furanone, trans-rose oxide, and rose oxide contents were significantly higher in SPWTs than in APWTs, which may result in stronger flowery, fresh, and sweet aromas in SPWTs than in APWTs. Among these, (2E,4E)-2,4-octadienal and (-)-cis-rose oxide can be identified as key volatiles. This study provides an objective and accurate basis for classifying SPWTs and APWTs at the metabolite level.

Differences of Typical Wuyi Rock Tea in Taste and Nonvolatiles Profile Revealed by Multisensory Analysis and LC–MS-Based Metabolomics

“…Therefore, the thickness had a positive correlation with almost all critical metabolites. The thickness had a positive correlation with most of the tea polyphenols, which was also found as a contributor to the thickness of white tea . The thickness was also positively correlated with most of the organic acids except shikimic acid, which is in agreement with the result of Fan et al The numb sensation showed a significantly positive correlation with 4- p -COQA and quercetin-3- O -β- d -glucoside.…”

“…The thickness had a positive correlation with most of the tea polyphenols, which was also found as a contributor to the thickness of white tea. 26 The thickness was also positively correlated with most of the organic acids except shikimic acid, which is in agreement with the result of Fan et al 40 The numb sensation showed a significantly positive correlation with 4-p-COQA and quercetin-3-O-β-D-glucoside. The astringent mouthfeel was positively correlated with catechins, kaempferol, quercetin, and myricetin derivatives and organic acids.…”

“…Astringency had a positive correlation with harshness (contrary to smoothness), and umami had a negative correlation with thickness. Analogously, a previous study reported that as the storage time increased, the freshness and astringency gradually decreased, whereas the intensities of smoothness and thickness increased . As umami and freshness both use the Chinese character of “xian,” the umami taste in tea may represent the sensation of freshness.…”

“…Analogously, a previous study reported that as the storage time increased, the freshness and astringency gradually decreased, whereas the intensities of smoothness and thickness increased. 26 As umami and freshness both use the Chinese character of "xian," the umami taste in tea may represent the sensation of freshness. Therefore, umami and thickness and astringency and smoothness may be two sets of opposing sensory attributes.…”

Variations of main quality components of matcha from different regions in the Chinese market

“…The technology we use was widely-targeted volatile method, and the method of reference ( 21 ) was followed with minor changes. DB-5MS capillary column (30 m × 0.25 mm × 0.25 μm, Agilent J&W Scientific, Folsom, CA, United States), the flow rate of GC carrier gas (helium) was 1.2 mL/min, the temperature of the injection port was 250°C, no shunt injection, and the solvent is delayed for 3.5 min.…”