Scientific Development Research

As a fully fermented tea, the fermentation degree plays a crucial role in flavor compound transformation. This study investigates the relationship between fermentation extent and flavor compound transformation patterns. With increasing fermentation intensity, tea polyphenols undergo oxidative polymerization under enzymatic action, leading to a significant decrease in content. The oxidation products—tea flavonoids and tea redones—first increase then decrease, while tea brownins persistently rise. Tea flavonoids impart freshness and brightness to the tea infusion, tea redones influence concentration and mellowness, while excessive tea brownins result in bland and dark flavors. Free amino acids increase during early fermentation but decrease later due to multiple reactions, affecting the teas umami profile. Soluble sugars coexist with consumption during fermentation, playing a vital role in shaping the teas sweetness, mellowness, and aroma.

Black tea; Fermentation extent; Flavor compounds; Transformation patterns; Quality improvement