Aroma is one of the critical aspects of tea quality which can determine acceptance or rejection of a tea before it is tasted. There are more than 630 compounds have been reported responsible in tea aroma.
The three basic types of tea; green, oolong and black have different quality characteristics, including aroma, taste and color, and appearance.
All of these aromas are generated from four main pathways: carotenoids as precursors, lipids as precursors, glycosides as precursors, and Maillard reaction pathway.
Carotenoids are important precursors of tea volatile compounds, especially the C9- to C13-aromas. Ionone and damascone are important C13-carotenoid-derived compounds that constitute an essential aroma note in black tea.
Tea contains many amino acids, but theanine, specific to the tea plant, is the most abundant, accounting for 50% of the total amino acids. Amino acid degradation is involved in the biogenesis of the tea aroma. Chlorophyll, carotenoids, lipids and volatile compounds are not major constituents in a tea brew but they also play an important role in the development of the aroma.
During black tea processing, including withering, rolling and fermentation, the lipids are degraded to produce flavor volatiles by hydrolytic or oxidative action of enzymes on glycolipids and phospholipids.
The major fatty acid derivatives include alcohols, aldehydes and lactones. C6 and C9 alcohols and aldehydes are key contributors to the “fresh green” odor of tea. Methyl jasmonate, an important fatty acid derivative, is a major contributor to the jasmine-like aroma of oolong tea.
Volatile compound responsible for aroma of tea
