Physicochemical and Volatile Flavor Changes Occurring in Fruit Juices During Concentration and Foam‐mat Drying

SUMMARY Various concentration methods were evaluated as to the effect they had on volatile losses during concentration of apple, sour cherry and peach juices. Freeze concentration resulted in the least loss. Diffusion‐membrane concentration resulted in slightly greater overall loss of volatiles but less than osmotic. Concentration by osmosis was slow and apple and cherry concentrates prepared by this method underwent a noticeable flavor change. Juice concentration by reverse osmosis was fairly fast and even though a large percentage of volatiles was lost, there was no detectable flavor change. Juices dried to a powder lost the largest amount of volatiles of any concentration procedure. The changes that occurred during drying could be organoleptically detected in all juices.