A membrane process for the recovery of a concentrated phenolic product from white vinasses

•Membrane technology is proposed to recover phenolic compounds from wine vinasses.•The final retentate is enriched in phenolic compounds with antioxidant activity.•The use of resins allows the recovery of phenolic compounds remaining in permeate.

A concentrated white wine vinasses stream (WV) was consecutively processed by a series of physical separation stages with two main targets; i) to produce a phenolic-rich product with antioxidant activity and ii) to reduce the initial pollutant load of WV. The optimal process could be defined based on a sequence of centrifugation and membrane filtration to selectively remove suspended and soluble solids and phenolic compounds. The final dried product contains 45% GAE (gallic acid equivalent) and presents an ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) radical scavenging capacity equivalent to almost 2 g of Trolox. The total carbon, total phenolics and the chemical oxygen demand (COD) in the permeate stream from the nanofiltration stage were reduced by 85.8, 85.1 and 91.8%, respectively. The toxicity, evaluated using the Microtox method, was significantly reduced from the EC50 values of 10−5% in the original stream to 1-7%.