Some molecular and colloidal aspects of tea cream formation

Research output: Contribution to journalArticlepeer-review

Authors

  • Marcel H.G.M. Penders
  • Donncha J.P. Scollard
  • Dave Needham
  • Edward Pelan
  • Alan P. Davies

Colleges, School and Institutes

External organisations

  • Unilever

Abstract

The formation of tea cream for a range of black tea materials was studied by turbidity measurements, time-resolved light scattering, gravimetric measurements and High Performance Liquid Chromatography (HPLC). These techniques demonstrate that, in the absence of caffeine and/or gallate esters the solubility of tea solids in black tea infusions is enhanced compared with the 'standard' black tea material. All the tea system show an increase in cream-point, amount of tea cream and particle size with increasing tea solids concentration. Decaffeination has a larger impact on enhancing the solubility of tea colloids than degallation. HPLC studies indicate that theaflavins have a preference for the cream phase, whereas ie. catechin C is preferentially partitioned into the aqueous supernatant phase. Caffeine is preferentially partitioned into the cream phase, albeit less favourably than theaflavins and other relatively high-molecular mass polyphenols. Comparison between 'standard' and decaffeinated black tea shows that in the absence of caffeine, epigallocatechin gallate (EGCG) is preferentially partitioned into the cream phase.

Details

Original languageEnglish
Pages (from-to)443-450
Number of pages8
JournalFood Hydrocolloids
Volume12
Issue number4
Publication statusPublished - 1 Jan 1998