Cold sterilization and clarification of pineapple juice by tangential microfiltration

Pineapple is a very appreciated tropical fruit due to its unique aroma and flavour. Pineapple juice was cold sterilised and clarified by crossflow microfiltration associated with an enzymatic treatment. A tubular polyethersulfone 0.3 μm pore size membrane with effective filtration area of 0.05 m2 was used in the pilot system. Ten experiments were carried out under the same operational conditions, 25°C and 100 kPa, in order to evaluate the cold sterilisation and clarification of pineapple juice by microfiltration. It was observed that the permeate flux did not change significantly after fifteen minutes of processing time. It was stabilised around 100 L/hm2. The clarification process was considered very efficient due to the great reduction of haze and viscosity, and by showing no significant changes in pH, acidity, sugar and soluble solid content of the juice. The permeate of the process was collected in sterile bottles inside a laminar flow station and kept under refrigeration (8°C) for a period of 28 d. The samples were submitted to microbiological evaluations in intervals of seven days. The microbiological analysis of the microfiltered pineapple juice showed that it was in agreement with the requirements by the Brazilian Legislation for juices and drinks.