Model parameters for single-droplet drying of skim milk and its constituents at moderate and elevated temperatures

ABSTRACT

Single-droplet drying experiments were conducted with solutions of dairy materials in water (skim milk and its constituents, namely lactose, whey protein, and a lactose–whey mixture) at both moderate and elevated temperatures, at which inflation/deflation phenomena are observed. The experimental data were used to obtain parameters of a spatially resolving single-droplet drying model, which was extended to empirically account for inflation/deflation. Inflation/deflation parameters and conditions for crust formation at the transition from the first to the second drying stage were clearly solute dependent, and respective correlations with drying conditions were developed for the investigated dairy materials. The parametrized model was shown to satisfactorily describe measured data in respect to drying curve, drying time, and the diameter of product particles.

KEYWORDS:

• Dairy products
• inflation/deflation
• single-droplet drying
• spatially resolving model

Acknowledgments

The authors also would like to thank Mr Rana Muhammad Irshad and Mr Usman Mazaffar Elahi, who contributed their MSc and BSc theses to the SDD measurements.