Permeate flux prediction in apple juice concentration by reverse osmosis

This work studies apple juice concentration by reverse osmosis (RO) using polyamide tubular membranes at different operating conditions. Permeate flux has been predicted by using the solution-diffusion model combined with the film model. Good agreement was found between the experimental values and the ones calculated by using both models. Pressure was found to be the most important variable controlling the process. Physico-chemical analyses were made in order to evaluate the quality of concentrated apple juice.