Effects of Gellan Gum and Homogenization Pressure on the Stability of Milk-Based Cocoa Beverages

Milk-based cocoa beverages are susceptible to physical instability, particularly sedimentation and creaming, because of the poor dispersibility and structural characteristics of cocoa particles. This study investigated the synergistic effects of gellan gum concentration and homogenization pressure on beverage stability using a Central Composite Rotatable Design. We evaluated water-holding capacity, sedimentation, creaming, pH, viscosity, and torque, and compared the optimized formulation with a commercial cocoa milk product. Particle size distribution, zeta potential, Fourier-transform infrared spectroscopy, optical microscopy, scanning electron microscopy–energy-dispersive spectroscopy, molecular docking, and sensory analysis were used to characterize the physicochemical, structural, molecular, and sensory properties of the beverages. The optimum conditions were identified as 0.04% gellan gum and a homogenization pressure of 214.82 bar. Under these conditions, the beverage exhibited a high water-holding capacity (93%), no detectable sedimentation, minimal creaming (0.012%), an apparent viscosity of 59.44 mPa·s, a reduced mean particle size of 309.9 nm, and a zeta potential of −38.73 mV. Molecular docking further supported the stabilizing role of gellan gum through hydrogen bonding, hydrophobic interactions, and electrostatic interactions with major milk proteins. The optimized beverage also, showed acceptable sensory properties and also, better physicochemical stability compared with the commercial product during nine months of refrigerated storage. Overall, the combined use of gellan gum and optimized homogenization pressure provides an effective strategy for producing stable, homogeneous, and high-quality milk-based cocoa beverages for industrial application.