Application of Ultrafiltration for Recovery of Bioactive Phenolic Compounds from Rose Wastewater

The process of rose oil distillation generates a huge amount of waste byproducts, which often remain unused, and poses serious environmental challenges; at the same time, they contain polyphenols with antioxidant, antimicrobial, and therapeutic properties. The purpose of this work is to investigate the possible application of ultrafiltration using three polyacrylonitrile membranes (molecular weight cut-off 1 kDa, 10 kDa, and 25 kDa) to recover the total polyphenolic compounds, phenolic acids, and flavonoids from rose wastewater. The permeate flux, energy demand, contents of total polyphenolic compounds, phenolic acids, and flavonoid phenolic compounds were determined during ultrafiltration at a volume reduction ratio of 2, 4, 6 and 8, and the rejections and concentration factors were established. The optimal operation conditions for permeate flux, energy demand, rejection, concentration factor, and antioxidant activity were established at a volume reduction ratio of 8, transmembrane pressure of 0.5 MPa, and 1 kDa membrane. These working conditions will be used in our future investigations to obtain extrudates from rice semolina enriched with ultrafiltered rose wastewater. Protocatechuic and vanillic acid, determined by HPLC, increased in the retentate when the 1 kDa membrane was used, while gallic acid, catechin, p-coumaric acid, rutin, hesperidin, and rosmarinic acid decreased.