Membrane fouling during the fractionation of phytosterols isolated from orange juice

The aim of this study is to isolate phytosterol compounds from orange juice using ultrafiltration (UF) flat sheet membranes (supplied by Alfa Laval) with molecular weight cut-off (MWCO) values of 10 kDa fabricated from regenerated cellulose, polyethersulphone and fluoropolymer. A cross-flow filtration rig operated at a transmembrane pressure (TMP) of 0.5-2 bar, and a cross-flow velocity (CFV) of 0.5-1.5 m s(-1). Membrane rejection towards total phytosterols, proteins, sugars were determined along with antioxidant activity. The regenerated cellulose membrane displayed the highest permeate flux (a pseudo steady-state value of 22 L m(-2) h(-1)), with a higher fouling index (75%) and a good separation efficiency of phytosterols (32% rejection towards phytosterols) from orange juice. Although the yield of phytosterols was relatively low (40 mg/L), there is a great potential to optimise the filtration process to produce commercially relevant amount of phytosterols. All membranes investigated displayed cleaning efficiencies of >95%. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.