Studies on the Enrichment of Black Tea Aroma

(Part 2) Estimation of Volatile carbonyl Compounds in Black Tea

Abstract

In order to make clear the relationship between the quality of volatile carbonyl compounds (VCC) and black tea aroma, the estimation method of VCC of black tea was studied.
Five g. of black tea in 150 c. c. of water was warmed at 150-160°C. in an oil bath and the distiled steam containing the essential oil was catched with the ice-cold 15 c. c. of 0.75N NaHSO₃ solution. After the excessive NaHSO₃ was oxidized with 1 N I solution and carbonyl-NaHSO₃ compound was decomposed with NaHSO₃, the isolated NaHSO₃ was titrated with N/100 I solution, and so the quantity of titrated N/100 I was equivalent to the quantity of VCC in the black tea.
The quantity of VCC of several black tea was estimated by this method and it was found that the better the aroma of black tea the less the quantity of VCC. (Sept. 1, 1956)