UHPLC-DAD-Based Determination of Phenolic Acids and Flavonoids in Ancient and Commercial Tea Samples

Tin, Kai Wen (2026) UHPLC-DAD-Based Determination of Phenolic Acids and Flavonoids in Ancient and Commercial Tea Samples. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Fermented and semi-fermented teas, including Pu-erh and Oolong tea derived from Camellia sinensis, are widely consumed due to their distinctive sensory properties and associated health benefits. These properties are largely attributed to phenolic compounds, which undergo significant transformation during fermentation and oxidation processes. This study aims to determine the phenolic profile of selected fermented and semi-fermented teas by focusing on key compounds, including gallic acid, chlorogenic acid, caffeic acid, p-coumaric acid, ferulic acid, salicylic acid, cinnamic acid, dihydroxybenzoic acid, rutin, and quercetin. High-performance liquid chromatography (HPLC) will be employed for the separation, identification, and quantification of these phenolic constituents due to its high sensitivity, precision, and suitability for complex plant matrices. The analysis will enable comparison of total phenolic content and individual phenolic distribution among different tea types, particularly between dark tea (Pu-erh) and partially oxidized tea (Oolong). Fermentation is expected to reduce simple catechins while increasing phenolic derivatives and polymerized compounds, thereby influencing antioxidant activity and overall tea quality.