Concentration of passion fruit juice on an industrial pilot scale using osmotic evaporation Original Research Article

Osmotic evaporation to concentrate clarified passion fruit juice was tried out on an industrial scale. A pilot plant that was equipped with a module containing 10.2 m2 of polypropylene hollow fibres was used to concentrate passion fruit juice up to a total soluble solids (TSS) content higher than 60 g/100 g at 30°C. Tangential velocity, temperature and concentration of solutions significantly influenced evaporation flux. An average evaporation flux of almost 0.75 kg h−1 m−2 was obtained with water, 0.65 kg h−1 m−2 when juice was concentrated to 40 g TSS/100 g and 0.50 kg h−1 m−2 when it reached 60 g TSS/100 g. A long-term trial, lasting 28 h, was successfully carried out without membrane fouling. Osmotic evaporation can be also conducted as a multistage procedure, giving a constant evaporation flux of around 0.62 kg h−1 m−2 when juice was concentrated from 14 to 60 g TSS/100 g. Sensory quality and vitamin C content were well preserved in the concentrated juice.