Emulsifying properties of water soluble yellow mustard mucilage: A comparative study with gum Arabic and citrus pectin

The emulsifying properties of water soluble yellow mustard mucilage (WSM) were compared with two commercial emulsifiers-gum Arabic and citrus pectin. Of the three polysaccharides examined, WSM exhibited excellent emulsion stability under various conditions applied in this study. The emulsion stability test showed that 1% and 2% WSM emulsions exhibited no phase separation after 21 days of storage at 25°C. WSM also exhibited the highest surface activity among the three materials. The surface activity of 1% WSM is equivalent to that of a 15% gum Arabic solution. When exposed to heat at 90°C for 20min, WSM emulsion showed little change in droplet size, which was superior to both the gum Arabic and pectin emulsions, whose droplet size increased significantly following heat treatment. WSM emulsion also had a significantly larger magnitude of zeta-potential than the other two polysaccharides. Under different pH conditions, droplet size varied greatly among the three materials. WSM emulsions exhibited significantly smaller droplet size at pH 4.0 followed by pH 9.0 and 6.5. Pectin emulsions and gum Arabic emulsions were not sensitive to the pH range examined in this study. WSM also showed the best freeze-thaw stability among the three polysaccharides. After three freeze-thaw cycles, the 0.5% WSM emulsion exhibited a higher cream index than 2% gum Arabic emulsion or the 1% pectin emulsion.