Effect of ultrasonication on rheological aspects and storage stability of O/W emulsions containing Gleditsia caspica galactomannan – Trigonella foenum – graceum galactomannan mixtures

Abstract

In current study, the effect of ultrasonication on rheological aspects and storage stability of oil-in-water emulsions containing Trigonella foenum – graceum (fenugreek) – Gleditsia caspica mixtures was comprehensively investigated. Power law, Carreau and Figuni – Shoemaker models were considered as best (by evaluating R2 and RMSE values) to fit the shear rate – shear stress, shear rate – apparent viscosity and shear stress – time data. The results of strain and frequency sweep tests demonstrated that control samples (without ultrasound treatment) had viscous like (dilute) behavior. Contrarily, samples treated with ultrasound had gel like (weak gel) behavior. Between utilized galactomannans, Gleditsia caspica galactomannan had more effect on all calculated rheological parameters. Also, existence of both galactomannans in the formulation of emulsions led to better and more enhanced rheological aspects in comparison with samples containing only one galactomannan. This could be attributed to intermolecular bonds and proper interactions (synergistic interactions) between galactomannans which resulted in more stable emulsions.