CLARIFICATION OF ORANGE JUICE USING CERAMIC MEMBRANE AND EVALUATION OF FOULING MECHANISM

This work reports microfiltration (MF) studies of orange juice using low-cost ceramic membrane prepared from locally available inorganic precursors. Characterization of the prepared membrane was carried out using scanning electron microscopy analysis, porosity determination and pure water permeation experiments. The average pore diameter, total porosity and hydraulic resistance of the membrane were evaluated as 0.285 mu m, 23.6% and 9.26 X 1011 m2/m3, respectively. Dead-end MF experiments were performed for both centrifuged orange juice (CJ) and enzyme-treated centrifuged orange juice (ETCJ). It was observed that after MF, important properties like total soluble solid, pH, acidity and density of both CJ and ETCJ were almost unaffected. However, significant improvement in juice color, clarity and alcohol insoluble solid was observed. Permeate flux of 5.32 X 10-6 and 13.23 X 10-6 m3/m2.s were observed after 30 min of experimental run at 137.9 kPa trans-membrane pressure drop (?P) for CJ and ETCJ, respectively. Various membrane pore blocking models were used to analyze the observed permeate flux decline. PRACTICAL APPLICATIONS The obtained microfiltration data for ceramic membrane-based clarification of orange juice could be useful to aid process design, development and operation studies for low-cost ceramic membrane technology-based juice processing systems. Pertinent flux decline behavior indicating the relevance of cake filtration model further indicates the applicability of membrane technology for juice processing applications with the fact that reversible membrane fouling is a proximate consequence of cake filtration and suitable cleaning procedures could enable long life span of the membrane. Enzyme treatment followed with membrane-based clarification of orange juice is found to be effective even from preservation and storage perspective.