Solvent-resistant ultrafiltration to recover bioactive compounds from wet olive pomace extracts

Integrated Membrane Process in Organic Media: Combining Organic Solvent Ultrafiltration, Nanofiltration, and Reverse Osmosis to Purify and Concentrate the Phenolic Compounds from Wet Olive Pomace

“…If those results are compared with this work, it is noticeable that lower rejections of biophenols are obtained when the extract is solvent-based. In a non-aqueous, organic media, as is the hydroalcoholic extract of wet olive pomace, the polymers of ultrafiltration membranes can suffer a pore enlargement as a result of the solvent contact, leading to a decrease in rejection [26,29], as was observed here.…”

“…In the current literature, there are no previous studies dealing with the ultrafiltration of a solvent-based extract of wet olive pomace in cross-flow mode. To the best of our knowledge, the only related work regarding this topic is a previous study from our research group, consisting of a screening of ultrafiltration membranes in a bench-top, stirred cell to treat the hydroalcoholic extract of wet olive pomace [29]. In that study, the UF010104 and UP005 membranes were also tested, but they displayed much lower values of permeate flux than those obtained in this work, whereas the solvent permeability was similar.…”

“…As a consequence, the potential complexation between these different molecules would increase the size of the solutes and increase their retention. Thirdly, the presence of this organic solvent (ethanol/water 50:50 v/v) has previously been demonstrated to reduce the hydrophilicity of UF010104 and UP005 membranes [29]. In this scenario, a reduction in the affinity of sugars (which are polar molecules) and the active layer of the membranes also supports a reduction in the permeation of these compounds.…”

“…Only a few contributions dealing with membrane filtration of a hydroethanolic extract of wet olive pomace have been published to date. In a previous study by the authors, the potential of ultrafiltration to reduce the organic load of the hydroalcoholic wet olive pomace extract was demonstrated, while the phenolic compounds were purified in the permeate [29]. Later, the authors also studied the performance of several nanofiltration membranes to treat a hydroalcoholic model solution whose composition was based on the extract of wet olive pomace obtained with ethanol/water 50:50 (v/v) [30].…”

“…Subsequently, the extract was ultrafiltered at 2 bar for the UF010104 membrane and at 2.5 bar for the UP005 membrane, with a cross-flow velocity of 1.8 m•s −1 and 25 • C. These operating conditions were selected according to previous studies from our research group [23,29]. The process was carried out in concentration mode until a VRF of at least 2 was achieved.…”