Inhibition of browning of apple slice and juice by onion juice

Abstract

The effect of onion juice on the browning of slices and juice of apple was examined. The browning of apple slices was completely suppressed by dipping them in onion juice diluted with an equal volume of water for 10 minutes. The browning of apple juice was, likewise, inhibited when the 50% apple juice was prepared by the addition of an equal volume of onion juice. Though the polyphenol oxidase activity of the apple was inhibited about 80% by the onion juice, 20% of activity still remained. Because the reaction liquid does not change to yellow, even if the reaction progresses in this condition, it was suggested that the formation of the browning material had been inhibited by the onion juice reacting with the product by 20% the remainder polyphenol oxidase activity.