Permeate flux and fouling resistance in ultrafiltration of depectinized apple juice using ceramic membranes

Raw depectinized apple juice was clarified in a laboratory scale ultrafiltration system using ceramic tubular membranes (Tech-Sep Carbosep) with a molecular weight cut-off of 300,000, 50,000, and 30,000 Da. The experiments have been carried out over a wide range of transmembrane pressures (100–400 kPa), temperatures (20–55 °C), and feed flow rates (100–900 ml/min). Permeate flux significantly decreased with time until a steady-state was established. The steady-state permeate flux reached a maximum at a transmembrane pressure of about 200 kPa. Higher permeate flux was obtained at higher temperatures due to lower permeate viscosity. The steady-state permeate flux was proportional to the feed flow rate raised to powers ranging between 0.22 and 0.31. All the membranes studied produced the clarified juice with a satisfactory clarity and color intensity value.