Performance of hollow Fiber ultrafiltration membranes in the clarification of blood orange juice

The clarification of blood orange juice by ultrafiltration (UF) was investigated by using three hollow fiber membrane modules characterized by different membrane materials (polysulfone (PS) and polyacrylonitrile (PAN)) and molecular weight cut-off (MWCO) (50 and 100 kDa). The performance of selected membranes was investigated in terms of productivity and selectivity towards total anthocyanin content (TAC), total phenolic content (TPC), and total antioxidant activity (TAA). All selected membranes allowed a good preservation of antioxidant compounds; however, the most suitable membrane for the clarification of the juice was found to be the PS 100 kDa membrane. In optimized operating conditions this membrane exhibited steady-state fluxes of 7.12 L/m2h, higher than those measured for other investigated membranes. Rejections towards TPC and TAA were of the order of 17.5% and 15%, respectively. These values were lower than those determined for PS 50 kDa and PAN 50 kDa membranes. In addition, the PS 100 kDa membrane exhibited a lower rejection (7.3%) towards TAC when compared to the PS 50 kDa membrane (9.2%).