Membrane Clarification of Black Tea Extracts

Microfiltration (MF; 200 and 450 nm) and ultrafiltration
(UF; 25, 50, 100 and 500 kDa) membranes were
assessed for the clarification of black tea extracts. Rejection
of tea components including cream components increased
with decrease in membrane pore size. Clarity of membrane
processed extracts was excellent (∼4 Nephelometric Turbidity
Units) even after 30 days of refrigerated storage. UF-500
and MF membranes resulted in greater retention of original
colour, besides greater recovery of tea solids including polyphenols
in the clarified extract. Increase in feed concentration
affected the recovery while diafiltration improved the
solids recovery including polyphenols and theaflavins.
Highest productivity was achieved at 2 % feed concentration
followed by 0.6 %. Solids and polyphenols recoveries
obtained with 0.6 % feed concentration and MF-450 membrane
combination were unmatched with any other combination.
The results favoured employing MF as a means of
clarification of tea extracts, preferably at low feed concentration
which provided greater recovery and productivity,
adequately meeting the quality requirements of ready-todrink
tea beverages.