Development of a method for water determination in lactose

The determination of water content of lactose and the water activity, which is related to it, are important to assess its microbiological stability as well as its technical and commercial quality. Lactose is a very important product in the dairy sector, but also in the pharmaceutical domain. isture content in milk products is often determined by gravimetric oven drying at 102 ± 2 °C until an approximate constant mass is reached. All substances volatile under the conditions applied contribute to the mass loss observed, however, a difference between water and other volatiles is not made. Strongly bound water may, on the other hand, escape detection. This is particularly the case for lactose monohydrate, which occurs in nearly all dairy products. id errors caused by this fact, a method on the basis of the Karl Fischer titration was developed and tested in an international inter-laboratory trial in cooperation with the International Dairy Federation (IDF) and the International Organization for Standardization (ISO). The method is in the final stage for publication as an international standard.