Oolong tea is valued worldwide for its semi-fermented processing and complex floral, fruity, sweet, and mellow flavor profiles. Minnan oolong tea, in particular, is known for rich germplasm resources and strong market appeal. However, tea flavor is shaped by variety, origin, cultivation, and processing, making accurate evaluation difficult. Traditional sensory assessment can capture overall impressions but is affected by subjectivity and panel variation. At the same time, confusing market labels—such as the use of “Tieguanyin” as both a cultivar name and a product category—make it difficult for consumers and producers to verify variety and quality. These challenges highlight the need for reliable, objective, and standardized methods for tea identification.
A study (DOI: 10.48130/bpr-0026-0001) published in Beverage Plant Research on 29 April 2026 by Ailing Liu's team, Hunan Agricultural University, shows that integrating intelligent sensing with metabolomic profiling can distinguish Minnan oolong tea varieties and explain the chemical basis of their flavor differences.
The researchers collected fresh leaves from the core Minnan production region and processed all five varieties under the same oolong tea procedure, including withering, tumbling, fixation, rolling, drying, cloth-wrapped kneading, and final drying. A trained seven-member sensory panel first evaluated aroma and taste attributes. The results showed clear varietal differences: Baiya Qilan had a persistent orchid aroma; Huangdan showed floral and sweet notes; Mingke 1 presented a rich, balanced taste; Tieguanyin was marked by elegant orchid fragrance and “Yin rhyme”; and Foshou featured sweet, fruity, and woody characters. The team then used an electronic nose and electronic tongue to digitize aroma and taste signals. The electronic nose successfully separated the five varieties, with W3C, W6S, and W3S sensors playing important roles, while the electronic tongue highlighted bitterness, richness, and saltiness as key taste indicators. For non-volatile metabolites, ultra-high-performance liquid chromatography-tandem mass spectrometry identified 3,949 compounds, including flavonoids, phenolic acids, alkaloids, terpenoids, lipids, organic acids, and other metabolites. Multivariate analysis screened 65 key differential non-volatile metabolites as potential varietal markers. Quantification of caffeine, catechins, and L-theanine further explained taste differences: caffeine and catechins were linked with bitterness and astringency, while L-theanine contributed to umami and aftertaste. For aroma chemistry, headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography-quadrupole time-of-flight mass spectrometry identified 111 volatile compounds. Among them, VIP and relative odor activity value analyses revealed 14 key aroma-active compounds, including nerol, phenethyl alcohol, farnesane, methyl jasmonate, β-elemene, and δ-cadinene, which contributed to floral, fruity, sweet, citrus, orchid-like, rose-like, and woody notes. The team also constructed an aroma wheel to visualize the characteristic aroma profiles of the five Minnan oolong tea varieties.
Overall, the study provides a systematic way to connect tea variety, sensory perception, and molecular composition. By moving beyond subjective tasting alone, this integrated approach can help authenticate varieties, support quality traceability, guide flavor-oriented tea processing, and provide scientific evidence for improving Minnan oolong tea standardization. The findings also offer a useful model for studying other specialty teas where cultivar identity and flavor quality are closely linked.
###
References
DOI
10.48130/bpr-0026-0001
Original Source URL
https://doi.org/10.48130/bpr-0026-0001
Funding information
This work was supported in part by the National Natural Science Foundation of China (32341049, 32494780) and Research on the Roasting Process and Quality Characteristics of Zhangping Shuixian Tea (KH250223A).
About Beverage Plant Research
Beverage Plant Research (e-ISSN 2769-2108) is the official journal of Tea Research Institute, Chinese Academy of Agricultural Sciences and China Tea Science Society. Beverage Plant Research is an open-access, online-only journal published by Maximum Academic Press. Beverage Plant Research publishes original research, methods, reviews, editorials, and perspectives that advance the biology, chemistry, processing, and health functions of tea and other important beverage plants.