Bioinspired Oleic Acid–Triolein Emulsions for Functional Material Design

Abstract

Stimuli-responsive nanostructured emulsions can be utilized to innovate tailor-made materials in fields including biotechnology and food materials. This study reports the composition and pH-responsive colloidal and interfacial properties of the naturally abundant oleic acid–triolein–water emulsions, and applies the knowledge to the sustainable design of nanoemulsions. Small angle X-ray scattering, spinning drop tensiometry, multi-angle dynamic light scattering, cryogenic transmission electron microscopy, and electrophoretic mobility analysis are used to follow pH and ionic strength triggered nanostructural transformations and analyze emulsion particle size and stability. Energy input by vortexing is found sufficient to form emulsions under pH conditions that trigger a decrease in the oil–water interfacial tension. The lipid composition, solution pH, and ionic strength are discovered to influence the protonation of oleic acid, driving pH-triggered colloidal transformations in the emulsions. The findings from this study can guide the design of novel sustainable functional food emulsions at low-energy for instance for the solubilization and delivery of degradation sensitive nutrients.