Fruit juice concentration is one of interests in food industry because it serves as a preservation method and reduces transportation cost. A current method for fruit juice concentration is water evaporation in multiple-effect evaporator. To avoid the disadvantages, such as non-enzymatic browning and antioxidant degradation, the operation needs to be conducted at vacuum pressure and 60oC of temperature. However, excessive heat in treatment process of fruit juice concentration still results reduction of nutrient content and overall quality. To date, the research on fruit juice concentration by Membrane Distillation (MD) technology has been attracting attentions due to low operating temperature. Process intensification of MD-Osmotic Distillation (OD) to increase mass transfer driving force has shown promising results and further studies on MD-OD application of fruit juice concentration are important to reduce operational cost of fruit juice industry and to preserve nutrient content in fruit juice.
A feed tank was heated in a water bath at various temperature. A hollow fiber membrane was submerged in the feed tank to obtain evenly distributed temperature along the membrane module. Deionized water was used as cold solution in MD testing and circulated on the membrane tube by a peristaltic pump at various flow rates. Increase in deionized water in permeate tank was observed over constant period of time to determine membrane flux. In MD-OD operation, K4P2O7 was used as cold solution and the test was conducted according to the aforementioned method. Vitamin C and phenolic substance of the concentrated fruit juice were measured and compared to the fresh juice to determine nutrient preservation during MD-OD operation. Phenolic substance concentration was quantified by Folin-Ciocalteau method and Vitamin C concentration was measured by UV-Vis Spectrophotometer.
Contact Person:
Helen Julian, Ph.D. (helen@che.itb.ac.id)