Apples (image) University of Vienna Share Print E-Mail Caption Yet these apple slices are white -- but soon they will lose their 'fresh' color and turn brown by tyrosinases. Credit Copyright: University of Vienna Usage Restrictions The image may only be used with appropriate caption or credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.