Functionalization of Polymer Networks to Target Trans-Resveratrol in Winemaking Residues Supported by Statistical Design of Experiments

The present work aims to produce  functionalized polymer networks to target the bioactive molecule trans-resveratrol found in winemaking residues, specifically at grape stems. The synergistic choice of photoinitiation, polymerization composition, and molecular imprinting approach allows the functionalization of these materials. Experimental design is applied to methodically perform the syntheses. The amount of crosslinker, the total monomer's concentration, and the ratio of trans-resveratrol to the functional monomer 4-vinylpyridine (4VP) are the factors selected for this experimental design. The binding capacities and the selectivity of the synthesized materials are assessed through sorption experiments in acetonitrile and hydroalcoholic media. Consequently, a multivariate linear regression analysis leads to describe the uptake of trans-resveratrol by the materials in both media. The crosslinker content and the ratio of trans-resveratrol to 4VP are found to be impactful parameters while designing such materials. These studies allow the identification of working conditions for sorption/desorption processes combining a high retention capability of the adsorbents with selectivity. Furthermore, four materials are selected to enrich trans-resveratrol from grape stems extracts in a continuous process of solid-phase extraction. The results show that the functionalized materials are able to enrich 12-fold the content of trans-resveratrol in some fractions demonstrating the interest of such polymers.