Amylase is responsible for the digestion of carbohydrates, amylase is an enzyme that breaks starch down into sugar. Amylase is present in human saliva, where it begins the chemical process of digestion. Foods that contain much starch but little sugar, such as rice and potato, taste slightly sweet as they are chewed because amylase turns some of their starch into sugar in the mouth. Lactase is an enzyme that hydrolyzes milk sugar (lactose) into its component parts, glucose and galactose, and assists in the digestion dairy products such as, ice cream, milk and cheese. Nutritionists estimate that 10-20% of the U.S. population is lactose intolerant, meaning they have an inability to break down lactose in many of the dairy products they eat.