Vacuum membrane distillation for the treatment of coffee products

Vacuum Membrane Distillation (VMD) was applied in two production lines of the coffee industry: the concentration of the coffee extract and the dehydration and recovery of caffeine. Experiments were carried out by using a commercial flat microporous membrane made of polypropylene (0.2 ?m pore size). Both systems worked with a vacuum value of 4 mbar, while the temperature was fixed at 45 °C and at 27 °C for the caffeine recovery and the coffee extract concentration, respectively. Starting from an extract of 13 wt%, it was possible to concentrate it up to the values needed for the instantaneous/soluble coffee production, while dry caffeine was recovered from a 0.1-0.3 wt% aqueous feed. In both case studies, a pure distillate stream, able to be re-used in the plant, was obtained.