blueberries and blackberries. bananas: they get slimy and dark really fast. apples: they absorb the color of the darker fruits (strawberries) quickly making them look less appealing (in my opinion). hey, i'm just saying.... it can be pretty tedious to cut up all the fruit and prep & bake all of the cinnamon sugar...
(no need to multiply either reaction by another factor). starch/iodine complex. the color formed by reaction between starch and iodine is much more intense than the color of iodine itself, so that the end point can be determined more sensitively with than without starch. the starch, a few mls, is added...