Soy lecithin and ethyl lauroyl arginate mitigate pH sensitivity and oxidative degradation of sucrose...

Sucrose monopalmitate (SMP) is a promising surfactant for stabilizing emulsions, but it is limited by poor stability in acidic conditions. Secondary-surfactants, soy lecithin and ethyl lauroyl arginate (LAE) were used to increase physical and oxidative stability. Soy lecithin introduced a negative charge that enhanced electrostatic repulsion and prevented droplet aggregation in SMP-stabilized emulsions at pH 3. Lecithin also possesses antioxidant properties at higher proportions (>60 w/w%). LAE, a cationic surfactant, increased electrostatic repulsion between oil droplets and stabilized SMP-stabilized emulsions at low pH. As a secondary surfactant, LAE reduced lipid oxidation by repelling cationic metal ions. At a ratio of 20% LAE to 80% SMP, emulsion droplet size decreased by >90% in acidic conditions, and lipid oxidation, measured by thiobarbituric reactive substances (TBARS), decreased by >90% in neutral conditions. The emulsion properties were optimized by manipulating the interfacial composition to produce emulsions for use in food and beverage applications.