Concentration of noni juice by means of osmotic distillation

Osmotic distillation (OD) or osmotic evaporation (OE) is a promising membrane process generally applied to concentrate solutions under isothermal conditions. In this work, this process was applied to concentrate commercial noni juice (Morinda citrifolia). Several nutraceutical properties have been reported for noni-derived products, mainly associated to the phenolic content of the fruit. The analyzed system is an osmotic distillation system where the solutions are circulated through a hollow fiber membrane contactor operating in transient configuration with circulation rates between 0.1 and 1.0 L min−1 and concentrated solutions of CaCl2 were used as extraction brine. At isothermal conditions (30 °C), transmembrane vapor water flux was experimentally determined from 0.090 up to 0.413 kg h−1 m−2. Noni juice was concentrated from 8 to 32 °Brix after 60 min of treatment. The content of phenolic compounds was preserved after this processing. Simulation algorithms based on phenomenological equations of heat and mass transfer were developed considering a resistances-in-series model to predict the performance of the process from theoretical information. The values of transmembrane water flux obtained by simulations showed deviations between 2.35 and 16.19% with the experimental ones for the operating conditions applied in this work.