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.

This work aimed to study the flux behavior, rejection and concentration factors, and energy demand to establish the optimal conditions during ultrafiltration of sweet buttermilk to produce ice cream. The experiments were conducted with a UF25-PAN membrane at a transmembrane pressure of 0.2, 0.35 and 0.5 MPa, and a volume reduction ratio (VRR) of 2, 3, 4, and 5. Total protein, fat, ash, and dry matter contents, phospholipid composition, and acidity of retentates and permeate were determined. The increase in the VRR led to a decrease in the permeate flux and an increase in the energy demand, rejection, and concentration factors of the main components of sweet buttermilk. The highest values of rejection and concentration factors established for fat were 98.65% and 4.93, respectively. The permeate flux and energy demand increased with the rise in the transmembrane pressure. The total phospholipids increased 2.8 times at VRR 5 compared to the initial buttermilk. The use of VRR 3 gave the best ratio between the permeate flux, the energy demand, and relatively high values of concentration and rejection factors. The use of VRR 5 will enrich the ice cream to the greatest extent to obtain a product with the highest level of biologically active substances (proteins, phospholipids, minerals).

The purpose of this work was to investigate the posibilties of ultrafiltration with 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 volume reduction ratio of 2, 4, 6 and 8, and the rejections and concentration factors were established. The permeate flux decreased with the rise in the volume reduction ratio, and with the decrease in the transmembrane pressure and the molecular weight cut-off of the membranes. Inverse relationship was observed between the permeate flux and the energy demand at the same operating conditions. The rejections and concentration factors of total polyphenolic compounds, phenolic acids and flavonoid phenolic compounds rose with the increase in the volume reduction ratio for all membranes. The 1 kDa membrane had higher concentration and rejection effectiveness than 10 and 25 kDa membranes. Protocatehuic and vanillic acid, determined by using HPLC, increased in the retentate when 1 kDa membrane was used, while gallic acid, catechin, p-coumaric acid, rutin, hesperidin, rosmarinic acid decreased.