To investigate the effects of drying methods on the structure and functional properties of casein micelles with partially removed β-casein, this study prepared micelle powders using three drying methods including freeze-drying (FD), freeze spray-drying (FSD), and spray-drying (SD).The influence of different drying methods on the structure was elucidated through techniques such as particle size analysis, ζ-potential measurement, Fourier-transform infrared spectroscopy (FTIR), intrinsic fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and transmission electron microscopy (TEM).Furthermore, the effects of drying methods on functional properties, including solubility, emulsifying capacity, and foaming ability, were explored.The results showed that FD treatment had a minor impact on protein structure and better preserved the natural micelle structure.FSD treatment, which combined low-temperature atomization with freezing, maximized the retention of micelle structure and functional properties, exhibiting favorable solubility, emulsifying activity index (EAI), and foaming capacity (FC) of (84.5±0.82)%, (12.34±0.17) m2/g, and (100±1)%, respectively.In contrast, although SD treatment reduced the loss of calcium and phosphorus to some extent during processing, it caused significant damage to protein structure and functional properties, leading to notably lower solubility (68.67±1.55)%, EAI (7.67±0.93) m2/g, and FC (53±3)%.This study clarified the effects of drying methods on the structure and functional properties of partially β-casein-depleted casein micelles, providing a theoretical basis and data support for their development and utilization and expanding their application potential in functional dairy products and protein ingredients.
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