Concentration processes for liquid foods containing volatile flavours and aromas

Three concentration processes are technically feasible for the selective dewatering of liquid food, viz. evaporation with aroma recovery, freeze concentration and reverse osmosis. Concerning quality preservation the freeze concentration is superior to the other two processes. the process is not yet developed to full technical maturity, however. It seems likely that in the coming years it will deprive the established evaporation process of its monopoly position. Reverse osmosis has not yet passed the laboratory scale stage. Because membranes with acceptable permeabilities are not very selective, it can be expected that their technical application in dewatering aroma‐containing liquid foods will remain restricted to some specialties. The costs of concentration are about the same for evaporation and freeze concentration. the higher investment costs of the latter process are partially offset by lower costs of energy. Depending upon the capacity and yearly operation hours the costs vary between ±5 and ±15 per ton water removal. Reverse osmosis may become competitive at more than 100 operation days per year.