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Changes of phenolic compounds of tea leaves during Oolong tea process

Tram Ngoc Nguyen 1, *
Oanh Ngoc Huynh 1
Hien Phuoc Phan 2
  1. University of Technolotry, VNU- HCM
  2. Nong Lam University, HCMC
Correspondence to: Tram Ngoc Nguyen, University of Technolotry, VNU- HCM. Email: pvphuc@vnuhcm.edu.vn.
Volume & Issue: Vol. 17 No. 1 (2014) | Page No.: 67-75 | DOI: 10.32508/stdj.v17i1.1271
Published: 2014-03-31

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Copyright The Author(s) 2023. This article is published with open access by Vietnam National University, Ho Chi Minh city, Vietnam. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0) which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. 

Abstract

It was believed that provided photographs of changes of total polyphenols (TPP), tannin, theaflavins (TF), thearubigins (TR) contents and total colour liquids. Green tea leaves were going through the stages: fresh tea → withering → incubated 1 → aromatic spin 1 → incubated 2 → aromatic spin 2 →fried inactivated enzymes. Tea samples in the stages were provided by Cau Tre tea factory. Tea samples were divided into two groups: the activated and inactivated enzyme groups – microwave was applied to treated the activated enzyme one. Tea samples after the inactivation were conducted. The results showed that TPP and tannin contents generally decreased. Changes of theaflavin contents were contrast to tannin contents. On the other hand, theaflavin and thearubigin are the major polyphenols that determine on the quality of Oolong tea.

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