Does a ripe orange have more vitamin C than an unripe one? You can test this using an iodine-starch solution. When iodine-starch meets vitamin C it turns clear. Once all the vitamin C is used up the solution stays blue. You squeeze juice from three oranges at different stages: unripe, half ripe, and fully ripe. You measure 100 ml of each juice and add iodine-starch drops one at a time until the blue color stays. The unripe orange needs 13 drops before turning blue. The ripe orange needs only 8. Fewer drops means less vitamin C. So the unripe orange actually contains the most vitamin C.