Integrated membrane processes for the concentration of tomato juice

The results of preliminary experiments for the production of new tomato juices based on the introduction of a microfiltration (MF) stage before the reverse osmosis (RO) stage are reported. Ceramic multichannel membranes with an average pore size in the micrometer tenths were used in the MF stage to obtain a clarified serum to be concentrated by RO and a concentrated pulp to be used for remixing with the RO concentrate, in order to formulate new tomato juices. High temperature and pressure resistant spiral-wound RO membranes were used to concentrate the clarified serum up to 14-15 Brix with permeate fluxes around 20 L/m2h..

Integrated membrane processes have proven to be potentially very useful for the production of new tomato juices and concentrates. The permeate flux during the microfiltration concentration run does not rapidly decline over time and VCRs up to 2.5 can be easily achieved. However, above this value the risks of pore clogging due to the high viscosity of the pulp cannot be neglected. By treating the clarified serum the RO highly concentrated products that can be easily mixed with the MF concentrated pulps to formulate new juices with improved sugar content can be obtained.