Transportation of bioactive (+) catechin from its aqueous solution using flat sheet supported liquid membrane

• Carrier mediated SLM is employed for the first time for the transfer of catechin.
• Optimal pH, concentrations of carrier and ethanol: 4.0, 1.2 M and 0.4 M respectively.
• Improved stability of the SLM has been obtained.
• Catechin and its derivatives have been quantified in real tea extract of Assam.
• First ever SLM based transfer of catechin and its derivatives from real tea extract.

Transport of (+) catechin through a flat sheet Supported Liquid Membrane (SLM) has been investigated and reported in this paper. Liquid membrane (LM) was composed of carrier, tributyl phosphate (TBP) dissolved in aliphatic n-decane. Aqueous feed solution containing catechin was maintained at acidic (pH=4) condition using 0.1N HCl whereas ethanol was used as stripping agent. The SLM operation yielded 53% extraction and 49% recovery of the catechin at the optimum operating conditions viz. 100 mg L−1 initial feed concentration, 1.2 M TBP in the membrane phase, 0.4 M ethanol as stripping agent, 200 rpm stirring speed and 25 °C temperature. The SLM method was found reasonably stable using polyvinylidene difluoride (PVDF) as a support material that allows repeatability of use of same support-LM combination. Further, the above transport method was tested for the recovery of catechin compounds present in hot water extract of green tea leaves which contains mainly (+) catechin (65.6%) and (-) epigallocatechin (EGC) (33.8%). Thirty six percent of catechin compounds initially present in the tea leaves extract (269.3 mg L−1) was recovered at the optimum conditions which were slightly different from the optimum conditions achieved for synthesized catechin solution. Initial flux of transport for catechin compounds from tea leaves extract was found to be 19.17×10−9 g cm−2 s−1.