Effect of pretreatment on freeze-drying time of camel milk

Freeze-drying of camel milk is time-consuming due to its high density, protein, and fat content, which limits industrial application and increases energy demand. In this study, ultrasonic treatment (UT) and homogenization were applied as pretreatments prior to freeze-drying. A full factorial design (2 4 ) was used to evaluate process factors. Experimental trials were combined with mathematical modeling based on heat and mass transfer equations (Fourier’s law, Fick’s law, and dimensionless criteria Re, Pr, Nu). Pretreatment significantly improved drying efficiency: the drying time of camel milk was reduced from 28 h (control) to 22 h (treated samples), corresponding to a 21% decrease. Protein content and solubility were enhanced, while residual moisture decreased to 3–4%. The developed equations accurately predicted sublimation rates and drying kinetics, with R 2 = 0.95 confirming high model reliability. The integration of ultrasonic treatment and homogenization into freeze-drying provides a viable strategy for reducing drying time and improving product quality of camel milk. The established criterion equations and models support process optimization and industrial application.