As cancers

metabolic syndrome

cardiovascular diseases

and neurodegenerative diseases have become more prevalent in the 21 st century

tea is gaining agrowing popularity among consumers.Meanwhile

there is an increasing pursuit for the sensory quality brought by tea.Tea contains a number of aroma components

but only a few are associated with special aroma and make major contributions to sensory quality

which are referred to as"key aroma components".This article briefly reviews the key aroma components that determine the sensory quality of green tea

black tea

dark tea

oolong tea

white tea

and yellow tea.