Starch is a high calorie food that converts to sugar during the digestion process. This creates a concern for people who are observing a low calorie diet. Because of this, you may want to test different milk to determine if they contain starch and estimate their relative starch contents.
Many different milk groups contain a carbohydrate known as starch. Using an iodine solution, you can test for the presence of starch. When starch is present, the iodine changes from brown to blue-black or purple.