Pervaporation methodology for improving alcohol-free beer quality through aroma recovery

Abstract

Two different beers, a Special beer (5.5% ABV) and a Reserve beer (6.5% ABV) were pervaporated in order to recover aromas to be added to a low-alcohol beer (less than 1% ABV) and an alcohol-free beer (less than 0.1% ABV) to improve their sensory quality. Sensory analysis confirmed that this was accomplished. Through the pervaporation process, three flavor constituents of beer (isobutyl alcohol, ethyl acetate and isoamyl acetate) were analyzed in detail. Selectivities were roughly predicted by an easy model based on the Hildebrand solubility parameters for the polymer and the species in the solution. According to the model, a polymer will transmit a species almost perfectly if their solubility parameters coincide. This model helps to calculate the relative selectivities from solubility parameters and can provide guidance when choosing the membrane for specific separation requirements in food processing or other separation problems where pervaporation can be of great help.