Tóm tắt
AbstractTea ‘cream’ is a finely‐divided suspension of insoluble particles that forms when a strong infusion of black tea cools. This study not only confirms that the principal constituents of ‘cream’ are theaflavins, thearubigins and caffeine, but shows that ‘cream’ also contains smaller amounts of other flavonoids, non‐caffeine nitrogen compounds, chlorophyll, and inorganic material; all of which are present in the original black tea. The effects of caffeine, theaflavin and thearubigin content, also the composition of the thearubigins (as indicated by the E380/E460 value) of black tea, the strength of infusion, and the pH of the infusing water on the amount of cream formed in infusions were investigated. Evidence was obtained that creaming causes a partial fractionation of the thearubigins. A method for determining the ‘creaming power’ of tea is proposed.
