Study and optimization of the hydrodynamic upstream conditions during recovery of a complex aroma profile by pervaporation

Using a coupled pervaporation-mass spectrometry set-up, the degree of concentration polarization of wine-must aroma compounds was determined in two different flow-cell configurations as a function of the hydrodynamic conditions over the membrane. It was found that for compounds of high sorption coefficient for the respective membrane polymer, concentration polarization might not be overcome, even under turbulent feed flow conditions, contrary to what was observed with compounds of low sorption coefficients. For the recovery of complex aroma mixtures comprising both, it is shown that the hydrodynamic feed flow conditions therefore represent a further degree of freedom for tailoring the permeate composition, and hence the product quality. As a consequence, under defined conditions, concentration polarization can be a desirable phenomenon with regard to the final product quality rather than being considered detrimental to the process efficiency.