Effect of Drying Temperature, Heat Treatment and Gum Concentration on Emulsifying Properties of Farsi Gum

This study aimed at investigating the effects of drying temperature, heat treatment and gum concentration on emulsifying properties of Farsi gum, extracted from Amygdalus scoparia Spach. For this purpose, solutions of 3, 3.5, 4 and 5% concentration of Farsi gum were prepared. These solutions were heat treated at 65, 75 and 85 °C for 1 minute. Then, they were dried by spray dryer at 120,150, 165 and 180 °C. The 20% sunflower oil emulsions were prepared at 0.5, 1, 1.5, 2 and 3% concentration of Farsi gum. The results showed that a decrease in drying temperature made improvement in the emulsion ability and emulsion stability of Farsi gum; but heat treatment and gum concentration had no significant effect (p < 0.05) on the emulsifying properties of Farsi gum. Emulsions contained 1% Farsi gum were stabled after a week and creaming was not observed, also after a month, emulsion contained 2% Farsi gum was stabled. By increasing the drying temperature, creaming index decreased but gum concentration and heat treatment had no significant effect (p < 0.05) on creaming index. The average size of droplets of emulsion decreased with increasing concentrations of Farsi gum from 0.5% to 1.5%-2% but with increasing concentrations of Farsi gum to 3%, the average size of droplets of emulsion increased. Among the factors involved, only drying temperature had significant effect (p < 0.05) on size of droplets of the emulsions. Consequently, the average size of droplets increased with increasing drying temperature.