Identification of key flavor compounds and color substances in tea: a review

Abstract

Owing to their excellent and distinctive flavor characteristics, consumers worldwide are attracted to tea. Tea flavor is determined by both nonvolatile and volatile constituents, which together influence overall taste and aroma. Tea is generally classified into six categories: green, white, yellow, oolong, black, and dark teas. However, common questions often arise regarding which chemical compounds in these different types of tea contribute to their unique color and flavor profiles. This review outlines recent studies on the key flavor compounds and color substances of oolong, green, white, yellow, dark, and black teas. The aroma profile and color substances of the tea are significantly altered by modifying the withering, oxidation, and drying methods and durations during the tea manufacturing process. The key aroma compounds and their odor activity values vary significantly across these tea types. Among the six types, oolong, yellow, dark, and black teas have more complex aroma profiles and nonvolatile compounds than white and green teas do. Chlorophylls and their degradation products, along with polyphenolic compounds and their oxidation derivatives, collectively influence the color characteristics of each type of tea.