Physicochemical properties of oil in water emulsions prepared with irradiated gum tragacanth in acidic conditions

The addition of gum tragacanth (GT) as an emulsifier in oil in water systems can reduce the interfacial tension and stabilize emulsions. The major goal of this study was to investigate the particle size distribution, stability and rheological properties of 10% w/w oil in water emulsion at different pH conditions (2.5, 4, and 5.4) as affected by the addition of 0.5% w/w of previously irradiated (0, 1.5, and 3 kGy) GT. Irradiation treatment affected the stability of emulsions by changing rheological properties and parameters describing particle size. The extent of these differences was dose-dependent. Results indicated that using 1.5 kGy irradiated GT was more effective in providing optimum values of particle size and maximum emulsion stability. The least consistency coefficient (0.38 Pa s) and the most unstable emulsion were achieved in samples with pH 2.5 and the irradiated dose of 3 kGy. There was an increasing trend in the flow behavior index with the increasing irradiation dosage. Emulsions were less stable at pH 2.5 than at higher pH levels (4.5 and 5.5).