Comparação entre centrifugação e microfiltração na clarificação do suco tropical de maracujá = Comparison between centrifugation and microfiltration on the clarification of passion fruit juice

No sentido de desenvolver uma alternativa ao processo convencional decentrifugacao realizou-se neste trabalho um estudo da microfiltracao para clarificar o suco tropical de maracuja. A influencia da pressao transmembrana e do pre-tratamento enzimatico do suco, foram estudadas no processo de clarificacao por microfiltracao. Os ensaios de clarificacao por microfiltracao do suco tropical de maracuja foram realizados numa unidade de microfiltracao construida em aco inox. As membranas ceramicas usadas apresentam diametro medio de corte de 0,3 e 0,8 ƒÊm. Os niveis de pressao transmembrana foram de 1,0 e 3,0 bar num processo isotermico a 35oC. Os niveis de concentracao de enzima Cytrozym Ultra L utilizados no pre-tratamento do suco foram de 100 e 200 ppm. A condicao de microfiltracao que resultou num suco de boa qualidade foi com a membrana de 0,3 ƒÊm operada a 1,0 bar com suco pre-tratado com 100 ppm de enzima. Nesta condicao, obteve-se fluxo de permeado igual 56 kg h-1 m-2 e obtendo-se 100% na reducao de solidosem suspensao e 97% na reducao da turbidez. Comparativamente o processo de centrifugacao com o mesmo suco apresentou resultados praticamente equivalentes, mas com uma reducao de solidos suspensos inferior a de 100% observada para a microfiltracao, sendo a obtencao de um suco isento de particulas suspensas, um dos principais objetivosdeste trabalho.Aiming at n alternative to the conventional centrifuge process of clarification, this work presents a study of the microfiltration processes to clarify the tropical juice of passion fruit. The influence of transmembrane pressure and the enzyme pre-treatment of the juice were studied in the process of clarification by microfiltration. Tests of microfiltration for clarification of tropical juice of passion fruit were performed in a microfiltration unit built in stainless steel. The ceramic membranes used have diameter cut-off 0.3 and 0.8 ƒÊm. The levels of transmembrane pressureinvestigated were 1.0 and 3.0 bar in an isothermal process at 35oC. The concentrations of Cytrozym Ultra L enzymes used in the pre-treatment of the juice were 100 and 200 ppm. The condition that resulted into a better quality of micro filtered juice was with membrane of 0.3 ƒÊm at 1.0 bar operated with juice pre-treated with 100 ppm of enzyme. In this condition, a permeate flow equal to 56 kg h-1 m-2 was obtained and resulting in 100% reduction of solid matter and 97% reduction in turbidity. The process of centrifugation with the same juice showed equivalent results, but the reduction of suspended solids was lower than the observed for microfiltration. The microfiltration allowed obtaining a juice free of suspended particles, which was the objective of this work.