Development and characterization of foam-mat freeze-dried beetroot powders: Role of carrier agents in foam behavior, powder functionality, and tablet formation

This study investigates the development of foam-mat freeze-dried beetroot powders and examines the role of carrier agents, maltodextrin and xanthan gum, on powder functionality and tablet formation. All formulations contained egg white albumen (5 wt%) as a foaming agent, while compositions varied based on the presence of maltodextrin (5 wt%) and xanthan gum at various
concentrations (0.05, 0.1, or 0.2 wt%). Foams were prepared by whipping beetroot juice mixtures, followed by freeze-drying. The addition of maltodextrin slightly improved foam expansion (from ~450 % to ~460 %) and significantly enhanced foam stability, whereas xanthan gum significantly increased the foam stability, with no drainage observed at 0.1 and 0.2 wt% within 180 min.
However, foam expansion decreased to ~370% at 0.2 wt% xanthan gum content. Maltodextrin improved flowability (Hausner Ratio, HR: 1.29 vs. 1.32 for control) and reduced hygroscopicity (23.5 % vs. 26.0 %), while xanthan gum increased particle irregularity and cohesiveness, thus leading to higher HR values (up to 1.47) and poorer flow. The inclusion of xanthan gum also reduced powder solubility from ~92 % down to ~77 %. Kawakita analysis showed that maltodextrin and xanthan gum reduced plastic deformation and powder compactness. Tablets prepared from these powders exhibited reduced tensile strength and density compared to the control. Color analysis indicated that carrier addition increased lightness (L*) and decreased redness (a*), primarily due to pigment dilution and reduced compactness.