Influences of Ulva fasciata polysaccharide on the rheology and stabilization of cinnamaldehyde emulsions.

Emulsifying properties of water soluble polysaccharides from Ulva fasciata (UFP) were evaluated in cinnamaldehyde/water emulsions in terms of droplet size distribution, rheological properties, visual phase separation, and zeta-potential. The cinnamaldehyde/water (10%, wt/wt) emulsions were formulated and stabilized by different concentrations of UFP (0.1-4%, wt/wt). The obtained emulsions showed monomodal droplet size distributions with average droplet size (D[3,2]) below 1.0μm, when 3% (wt/wt) UFP was added as the emulsifying agent under a homogenization pressure of 75MPa. The rheological properties and zeta-potential of the emulsions appeared to be dependent on the UFP concentration. Furthermore, the UFP exhibited better emulsifying and stabilizing properties in the investigated system when compared to other commercial polysaccharides of gum Arabic and gum Ghatti. The results also suggested that the emulsifying and stabilizing mechanism of the UFP may not only be ascribed to its surface-active protein moiety, but also to the hydrophobicity of the polysaccharide itself. These findings provided a theoretical basis for potential utilization of UFP as a novel hydrocolloid emulsifying agent.