Impact of Inorganic Impurities on Lactose Growth Kinetics Determined by Large-Scale Interferometric Data Sets

Lactose crystallization from whey occurs in the presence of varying compositions of inorganic salts impurities. These impact lactose solubility, mutarotation, and crystal growth. Possibilities of predicting crystal growth rates based on given impurity compositions yield the chance to optimize the industrial lactose crystallization processes. To this day, model-based optimization efforts of lactose crystallization often lack kinetic parameters to accurately describe crystal growth in varying natural whey solutions. This study presents an extensive experimental data set of lactose crystal growth kinetics impacted by different impurities and process conditions, measured in a Jamin-interferometer setup. A parameter estimation was conducted to derive growth rate parameters for a variety of individual impurity concentrations as a function of α-lactose supersaturation and temperature. The obtained growth rates at different supersaturation levels, temperatures, and impurity profiles emphasize the complex interaction of whey salts and lactose. The kinetics presented in this study provide a comprehensive base for model-based process optimization.