Impact of Yarrow Phenolic Compounds on the Composition, Structure, and Thermal Properties of Lupin Protein‐Stabilized Oil‐in‐Water Nanoemulsions

Abstract

The effect of phenolic compounds extracted from yarrow ( Achillea millefolium L.) in the interfacial stabilization of oil–water nanoemulsions containing lupin protein isolate (LPI) was investigated. The extract contained a rich profile of flavonoids and phenolic acids, characterized using liquid chromatography. Nanoemulsions were stabilized with LPI. The apparent diameter of the droplets increased in the presence of the extract. The yarrow phenolics did not induce covalent aggregates of LPI, nor modify their electrophoretic migration, but induced changes in the thermal stability of the lupin protein. Specifically, the enthalpy of denaturation attributed to the β‐conglutin decreased while there was an increase in enthalpy at the higher temperatures, suggesting stabilization of the larger molecular weight protein fractions. The extract also contributed to a decrease in the interfacial tension, as measured by drop tensiometry. The viscoelastic properties of the interface were also modified, causing the formation of a more viscous interface compared to that of the native proteins. These findings highlight the potential of yarrow phenolics for modulating the interfacial structure of protein‐stabilized delivery systems, due to specific interactions between proteins and their polyphenolic components.