Effects of baking and aging on the changes of phenolic and volatile compounds in the preparation of old Tieguanyin oolong teas

Ying Jie Chen, Ping-Chung Kuo, Mei Lin Yang, Feng Yin Li, Jason T C Tzen

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

A series of old oolong teas was prepared by baking fresh Tieguanyin oolong teas at 120-140. °C for 72. h, followed by a long-term storage of 5, 10 and 20. years. To monitor the chemical changes of the tea preparation, phenolic and volatile compounds in a fresh or its newly baked tea were analyzed and compared with those in the three aged teas. The contents of phenolic compounds in the teas were apparently altered by the baking, but remained relatively stable thereafter in the aging process. The contents of major catechin derivatives and flavonol glycosides presumably responsible for astringency and bitterness of teas were reduced while those of gallic acid and gallocatechin gallate, putatively originated from the decomposition and isomerization of (-)-epigallocatechin gallate, were elevated after baking. In contrast, linear and branched hydrocarbons, the abundant volatile compounds in the fresh tea, were relatively stable in the baking process, but nearly diminished during the long-term storage. Relatively minor contents of substituted benzaldehydes and pyrrole derivatives probably rendering the unique flavor of old oolong teas were generated after the baking and aging processes.

Original languageEnglish
Pages (from-to)732-743
Number of pages12
JournalFood Research International
Volume53
Issue number2
DOIs
Publication statusPublished - 2013 Oct 1

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Tea
baking
volatile compounds
tea
phenolic compounds
epigallocatechin
chemical derivatives
pyrroles
astringency
benzaldehyde
bitterness
isomerization
rendering
Benzaldehydes
gallic acid
catechin
flavonols
glycosides
hydrocarbons
oolong tea

All Science Journal Classification (ASJC) codes

  • Food Science

Cite this

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abstract = "A series of old oolong teas was prepared by baking fresh Tieguanyin oolong teas at 120-140. °C for 72. h, followed by a long-term storage of 5, 10 and 20. years. To monitor the chemical changes of the tea preparation, phenolic and volatile compounds in a fresh or its newly baked tea were analyzed and compared with those in the three aged teas. The contents of phenolic compounds in the teas were apparently altered by the baking, but remained relatively stable thereafter in the aging process. The contents of major catechin derivatives and flavonol glycosides presumably responsible for astringency and bitterness of teas were reduced while those of gallic acid and gallocatechin gallate, putatively originated from the decomposition and isomerization of (-)-epigallocatechin gallate, were elevated after baking. In contrast, linear and branched hydrocarbons, the abundant volatile compounds in the fresh tea, were relatively stable in the baking process, but nearly diminished during the long-term storage. Relatively minor contents of substituted benzaldehydes and pyrrole derivatives probably rendering the unique flavor of old oolong teas were generated after the baking and aging processes.",
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Effects of baking and aging on the changes of phenolic and volatile compounds in the preparation of old Tieguanyin oolong teas. / Chen, Ying Jie; Kuo, Ping-Chung; Yang, Mei Lin; Li, Feng Yin; Tzen, Jason T C.

In: Food Research International, Vol. 53, No. 2, 01.10.2013, p. 732-743.

Research output: Contribution to journalArticle

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