The relation between the composition of dried skim milk and the texture and viscosity of white sauce in which the powder was a major ingredient has been investigated. The level of whey protein denaturation was inversely related to sauce viscosity. Modest increases in protein content of the powder, achieved by ultrafiltration, led to improvements in viscosity of white sauce. The effects were retained against a wide range of experimental protocols and both freshly prepared sauces and sauces which had been frozen then recooked.