Objective Repeated osmanthus scenting for processing Guihua Liubao Tea was evaluated.

Method Guihua Liubao Tea was made without scenting as control or with once to thrice repeated exposures to osmanthus flowers. Aroma and taste of the teas made as well as the brewed teas were evaluated by a sensory panel and chemicals analyzed using liquid chromatography. The data obtained were compared to determine the optimal times of scenting for the tea-making, based upon the functional and sensory quality as well as operational cost.

Result Floral scenting significantly imparted the osmanthus fragrance into the tea. Repeated scenting significantly accentuated the floral scent in the tea and improved the overall sensory perception with long lingering aroma and sweet, smooth taste of the brewed tea. However, the richness of the tea significantly declined with reduced concentrations of flavonoids, polyphenols, free amino acids, and caffeine. Even being scented merely once, the tea already showed significant decreases in polyphenols, theobromine, and free amino acids. And the second scenting further lowered the contents of flavonoids, water-soluble extracts, and ester-type catechins (e.g., EGCG and ECG) but increased those of the non-ester-type catechins (e.g., EGC and C). Hence, the critical functional catechin quality index of the tea was sacrificed due to the additional exposures as a result.

Conclusion It appeared that scenting once was preferable for making Guihua Liubao Tea. Although repeated scenting would indeed enhance the tea aromatically, one-time exposure to osmanthus flowers could produce a sufficiently rich, floral, sweet, smooth, and mellow tea that tasted less bitter with appealing functionality. It would also save an added production cost if extra step was included.