Lactose Hydrate Research Articles

Moisture Studies in Dry Products of Milk. II. Estimating Water of Crystallization of Alpha-Lactose in Dry Whey Solids

Summary A moisture desorption method has been developed for estimating the water of crystallization of alpha -lactose and indirectly the crystalline alpha hydrate itself in certain types of dry whey solids. It is based upon the difference in the rates of dehydration of crystalline alpha -lactose hydrate and other moisture adsorbing constituents and also upon the uni-molecular dehydration of the hydrate itself. Good recovery was obtained using mixtures of known composition of crystalline alpha -lactose hydrate and casein. Results obtained by this method were in close agreement with those by an indirect method in which the difference between total moisture as determined by the Karl Fischer method and “free” moisture as determined by an oven procedure was considered to be water of crystallization of alpha -lactose. Aside from an effect on the rate of dehydration, particle size, within the range of 54 to 210 μ , was found to have no influence on the results obtained by the moisture desorption method.

Moisture Studies in Dry Products of Milk. I. Kinetics of the Dehydration of Alpha Lactose Hydrate in Toluene

Summary The dehydration of lactose monohydrate in boiling toluene is found to be a first order reaction, the rate constant of which varies with particle size in accordance with the equation kd = 0.565, where k is the rate constant in min -1 and d is the average diameter of the particle in microns. The effect of the magnitude of the rate constant on the length of distillation period necessary for the quantitative determination of moisture for dry milk products by the toluol distillation method is discussed. The rate of distillation has some influence on the velocity of dehydration of lactose monohydrate, but above a distillation rate of 6ml. per minute any further increase in the distillation rate has no effect on the rate of dehydration.