Abstract
This study evaluates fluidized-bed drying of cottage cheese using a purpose-built swirl-chamber system designed to limit losses and thermal stress. The work addresses the need for stable dried dairy ingredients with retained nutritional quality and controlled structure. The system integrates tangential gas injection, rotary louver elements, and mechanical agitation to ensure uniform fluidization under controlled hydrodynamic conditions (gas velocity sufficient for stable fluidization without excessive particle entrainment or channeling). Drying behavior was examined for low-fat and semi-fat cottage cheese under linear heating (60 °C, 180 min) and short-time high-temperature treatment (200 °C for 3 min followed by 160 °C). Drying kinetics showed a strong dependence on formulation. A higher fat content promoted faster moisture removal and significantly lower final moisture, consistent with reduced water binding and delayed surface crust formation. Short-time high-temperature treatment reduced moisture content to residual levels within minutes. Microstructural observations revealed particle size reduction and increased structural uniformity after drying, confirming effective agitation and fluidization. Vitamin retention remained acceptable, while apparent mineral levels increased as a result of moisture removal rather than elemental transformation. The developed system reduced pressure losses, prevented particle backflow, and maintained stable fluidization across a broad particle size range. Overall, controlled fluidized-bed drying enabled efficient dehydration while preserving nutritional attributes and improving structural homogeneity, supporting the production of high-quality dried dairy ingredients for further food applications.