What color does a vitamin c indicator turn when apple juice is dripped on it?

A vitamin C indicator, such as DCPIP (2,6-Dichlorophenolindophenol), will turn from blue to colorless when apple juice is dripped onto it. This is because vitamin C, or ascorbic acid, is a reducing agent and the DCPIP is an oxidizing agent. In the presence of a reducing agent like vitamin C, DCPIP is reduced, causing its characteristic blue color to change to colorless. The amount of vitamin C present in the juice sample can be determined by measuring the time taken for the color change to occur.