Fruit Juice Processing by Integrated Membrane Operations

Fruit juice clarification, stabilization, depectinization, and concentration are typical steps where membrane processes such as microfiltration (MF), ultrafiltration (UF), reverse osmosis (RO), osmotic distillation (OD), and membrane distillation (MD) can be utilized as alternative technologies to the conventional transformation technologies. Particularly, MF and UF are valid approaches for the clarification of fruit juices as alternative to the use of fining agents, such as gelatin, diatomaceous earth, bentonite, and silica sol, which cause problems of environmental impact due to their disposal (Echavarria et al. 2011). Clarified juices coming from MF or UF processes can be commercialized or submitted to a concentration process in order to obtain a product suitable for the preparation of juices and beverages. RO, MD, and OD can be used as concentration techniques as alternative systems to Thermal evaporation or cryoconcentration (Jiao et al. 2004). Integrated membrane operations have been suggested for replacement of conventional juice processing unit operations for the clarification and concentration of different fruit juices as well as for the recovery of aroma compounds. A typical example of integrated membrane system for the clarification and concentration of fruit juices is depicted in Fig. 1. The fresh juice is clarified by UF; the clarified juice is pre-concentrated by RO and then concentrated by OD. Pervaporation (PV) is used to recover aroma compounds from the fresh juice.