Investigation of sage seed gum and whey- protein on the stability of the Oil-water emulsion with using response surface methodology (RSM)

Sage, an Iranian seed, can be used as a source of hydrocolloid in the stability of emulsions due to its high content of mucilage. On the other hand, whey-proteins have been recently introduced to the food industry as suitable emulsifiers. The aim of the present study was to investigate the interactive effects of sage seed gum and whey proteins on the stability of oil-in-water emulsions using response surface methodology. Emulsions were prepared with different concentrations of gum (0.2 -0.75 gr), protein (0.5-1.5 gr) and Sunflower oil (20-40 gr) in 80 ml water. Emulsion parameters including size, stability index, viscosity and emulsification properties were measured based on reference methods. The results showed that the droplet size decreased with increase in the concentration of the gum and the proteins, while increasing the amount of oil led to increase in the droplets size. Emulsification properties were also improved with increasing in the concentration of gum. The results also revealed that the emulsification properties improved with increasing the amount of protein; however no significant effect was detected at higher concentrations. The results of viscometery characteristics showed that flow behavior in all samples was non-Newtonian shear thinning and the Herschel-Bulkley was the best model for describing data. Addition of gum to the emulsions increased the viscosity significantly.