Effects of pretreatment and various operating parameters on permeate flux and quality during ultrafiltration of apple juice

Abstract

The central composite design with a quadratic model was used to investigate the effect of temperature (20-40°C) and transmembrane pressure (TMP) (100-300kPa) as well as pretreatment with gelatin and bentonite (0:0-300:1500mgL -1) on permeate flux and fouling resistance during ultrafiltration of apple juice. The changes in some physicochemical properties were also investigated. Pretreatment of apple juice with gelatin and bentonite and an increase in the temperature and TMP significantly improved the permeate flux. In general, physicochemical properties of apple juice other than polyphenolics were not affected by the applied parameters. Using 150mgL -1 of gelatin and 750mgL -1 of bentonite for fining significantly reduced the total phenolic content and so did the fouling resistance. Fouling resistance also decreased with increasing temperature, and increasing pressure increased the fouling resistance. © 2011 Institute of Food Science and Technology.