Wie kann man Lactose in Milchprodukten nachweisen?

Depending on the lactose content of the examined dairy product, a different degree of red color results after application of the Woehlk-test. In lactose-free milk the disaccharide lactose was enzymatically cleaved by the dairy into the two monosaccharides glucose and galactose, therefore the color is not red, but yellow. In light-red dairy products (kefir, natural yoghurt, ...) was the lactose partially digested by microorganisms e.g. to lactic acid. Dairy products with monosaccharides such as glucose and galactose (lactose-free milk) or fructose and glucose yoghurt dessert) become yellow.