Aroma recovery by integration of sweeping gas pervaporation and liquid absorption in membrane contactors

Abstract

An integrated process for recovering of aroma compounds from dilute natural matrices is proposed, combining the advantages of organophilic and sweeping gas pervaporation with gas–liquid absorption in membrane contactors. This process avoids the use of vacuum conditions and condensation steps for aroma recovery. Additionally, it presents the advantage of stabilising the target aroma compounds after being captured in a liquid absorbent, which is used as an additive in food and/or cosmetic products. After solubilisation in the selected absorbent the aromas may be delivered and released in the final product. In order to optimise this integrated process the conditions for sweeping gas pervaporation, namely the sweep gas linear velocity in the downstream circuit of the pervaporation module, were firstly optimised. Several potential food/cosmetic compatible additives were tested and their affinity towards the target aroma compounds was evaluated. High partitions of the aroma compounds to polyethylene glycol (PEG) 300 were observed, especially for hydrophobic esters, making possible to achieve an additional degree of selectivity. Finally, the absorption of aromas in a non-dispersive membrane contactor system was achieved under extremely stable operating conditions.