Ultrafiltration of skim milk has long been used to increase the solids level for a variety of dairy products from the cheese vat to cultured products. Ultrafiltration membranes restrict the passage of milk proteins and milk fat allowing the passage of water, lactose and milk mineral through the membrane. The result is a base milk product that can be diluted back to original milk volume with water, milk mineral and artificial sweetener to produce a "Low Carb" milk product. The level of carbohydrates can be reduced to 3 grams per 8oz serving with standard ultrafiltration. Carbohydrates of less than 3 grams can be achieved with the addition of diafiltration, or additional water, to the ultrafiltration system that removes more lactose from the product.
The same base milk product can be used in low carbohydrate ice cream formulations, cultured yogurts and other dairy based products. Below is a typical mass balance of Ultrafiltered milk: