Foam-Mat Drying of Camel Milk: Evaluation of Physicochemical Quality Attributes and Powder Properties

Camel milk is a nutritious but highly perishable dairy product, necessitating effective preservation methods to extend its shelf life and enable wider distribution while preserving its nutritional value. This study aimed to optimize the production of camel milk powder using the energy-efficient foam-mat drying technique. In this process, camel milk was mixed with whey protein concentrate (WPC) and gum tragacanth (GT) dispersion to form a stable foam. The foam formulation was optimized via Response Surface Methodology (RSM), with WPC (5%-15% w/w), GT (0.05%-0.2% w/w), and whipping time (1-4 min) as independent variables. Quadratic models for foam density and stability were significant, identifying WPC as the most influential factor. The optimized foam was dried at 50°C, 60°C, and 70°C. Drying kinetics were best described by the Page model (R ² > 0.99). The powder dried at 70°C exhibited superior quality: the lowest water activity (0.136), highest solubility (0.88), lowest bulk density (0.45 g/cm³), and highest lightness (L* = 89.39). Hygroscopicity increased slightly with temperature but remained within acceptable limits for dairy powders. Sensory evaluation showed no significant differences among samples, though the 70°C powder received the highest scores for taste (mean = 4.60) and overall acceptability (mean = 4.12). In conclusion, foam-mat drying at 70°C effectively produces a high-quality, shelf-stable, and sensorially acceptable camel milk powder, offering a promising alternative to conventional drying methods.