Solvent resistant diananofiltration for production of steryl esters enriched extracts

• Use of solvent resistant nanofiltration (SRNF) for production of bioactive extracts.
• Diafiltration enabled the removal of contaminants from deodistillates.
• A fully predictive model was developed to described the diafiltration process.
• The flux increase during diafiltration is explained by the swelling of the membrane.
• Strategies to increase the process efficiency are discussed.

Deodorizer distillate is a by-product from edible oil refining rich in bioactive compounds. However, its use as food additive is not allowed due to the presence of pesticides in relatively high concentrations. This paper discusses the technical feasibility of a solvent resistant membrane-based process for production of steryl esters-enriched extracts, using deodorizer distillates as raw material.A mass-balance based model was used to predict the profile of species concentration during diananofiltration processing of a hexane-based solution containing 5% (w/w) of deodorizer distillate. This tool enabled the comparison of three commercial SRNF membranes in terms of their discrimination between pesticides and steryl esters. PuraMemS600 from Evonik was identified as the best membrane, showing the best compromise between membrane flux and rejection behavior towards the compounds of interest. This membrane presented a constant rejection of steryl esters (95.5%) and a time-dependent flux, probably associated to swelling effects. Both the rejection and permeability data were used in the simulation of the diananofiltration process, making possible to obtain a good agreement of the model with the experimental data.The diananofiltration technique investigated in this work showed to be suitable for an efficient removal of pesticides, however, at expense of a significant loss of steryl esters of 42%. An alternative configuration of two-stage diananofiltration was simulated, suggesting an improvement of the efficiency of the process.