Abstract

Ultrafiltration (UF) performance to clarify apple juice was studied using a Carbosep® membrane of 15 and 50 kDa, tangential velocity of 2 and 7 m/s and transmembrane pressure of 150 and 400kPa. Effect of operating conditions on membrane fouling, process efficiency and juice quality were studied. Average permeate flux varied between 56 and 157 L/(m2h). The results indicate no unique optimum operating condition for the set of variables studied. Color, clarity and turbidity of juice improved significantly after UF. Deterioration of juice quality during storage was due to clarity loss, turbidity and post-bottling sediment formation. Clarity loss was modeled by zero-order reaction kinetics and shelf-life was determined. Pasteurized (65°C for 30 min) and UF apple juice had a shelf-life of at least 5 months, when stored in glass containers at 16°C in the dark. © 2003 Swiss Society of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.