Flaxseed Oil-In-Water Emulsions Stabilized by Multilayer Membranes: Oxidative Stability and the Effects of pH

The investigation of the effect of multilayer membranes on the stability of flaxseed oil-in-water (o/w) emulsions was the main goal of this study. The primary emulsion was prepared by homogenizing the oil phase (10 wt%) with an aqueous sodium caseinate solution (90 wt% and a pH 6.8) using a high-pressure microfluidizer. This emulsion was mixed with a pectin solution to form a secondary emulsion at a pH 6.8 and then adjusted to a pH to 3 for the adsorption of anionic pectin molecules on the surface of the cationic droplet surfaces. The pH effect on the physical stability of the emulsions was evaluated by measuring the mean particle diameter, ζ-potential, creaming index, and visualization of the microstructure. Also, the oxidative stability was determined by monitoring the lipid hydroperoxides and thiobarbituric acid-reactive substances (TBARs) at 55°C. The results of this study indicate that a multilayer structure had a positive effect on the improvement of the physical and oxidative stability of the conventional emulsions under certain pH conditions and limited storage period.