Scale-up of pervaporation for the recovery of natural aroma compounds in the food industry Part 2: optimisation and integration

Abstract

In this study the integration and optimisation of hydrophobic pervaporation for the recovery of natural aroma compounds in the food industry has been studied. The simulation developed in the first part of this study was applied to the design and scale-up of pervaporation units for the recovery of natural apple juice aroma. Both semi-batch and continuous process configurations were considered and the process conditions were optimised taking the cost of the process into account. For the semi-batch process, the cost per kg concentrated aroma was between 31.30 and 33.60 ▪, depending on the membrane type. When returning the recovered aroma to the apple juice after heat treatment, the cost of aroma recovery per kg concentrate was between 0.31 and 0.34 ▪. In the case of the continuous process, the cost for the apple juice aroma recovery was between 2.19 and 5.38 ▪, while the cost of aroma recovery per kg apple juice was between 0.03 and 0.05 ▪. Upon analysing the optimised processes with a sensitivity analysis of the key cost factors associated with pervaporation, membrane life-time and membrane cost, it was revealed that the membrane life-time is more important than the membrane cost and that the continuous process is more sensitive to changes in membrane life-time and membrane cost. Overall, this study revealed that pervaporation has the potential to become an alternative to conventional processes in recovering and concentrating aroma compounds in the food industry.