Advancement in Forward Osmosis (FO) Membrane for Concentration of Liquid Foods

Abstract

In food processing, concentration of liquid food is one of the important steps required for several purposes. Concentration of liquid food while preserving sensorial and nutritional components is quite challenging, especially for thermal-based concentrating processes. This is due to the significant loss of those components which are heat sensitive. Therefore, considerable efforts have been devoted to develop new concentrating processes which can solve this problem. Among the developed processes, forward osmosis (FO) has been considered as an interesting alternative since it can be operated at low operating pressure and temperature and obtain a concentrated solution with high solid contents. However, there are several challenges in FO operation e.g. fouling phenomena, concentration polarization, and reverse diffusion of solution from draw solution. To address these issues, several developments have been made to prepare membrane which has high hydrophilicity, low fouling tendency, reduced concentration polarization, and low solute diffusion. The desired membrane has been obtained, for example, by modifying selective and support layers of the membrane. This paper reviews advances in FO membrane, including membrane preparation and modification. Principle and important parameters of FO in concentrating liquid foods are overviewed. In addition, challenges and strategies in FO membrane preparation are discussed.