Shellac-based nanoparticles provide highly stable Pickering emulsions

This study investigates the hypothesis that modified shellac nanoparticles (NPs) can effectively stabilize Pickering emulsions. Shellac, a natural polyester resin derived from the secretion of insects, was chemically modified using Jeffamine® M600 and Jeffamine® ED2003 to produce two NP types: Sh-M600 and Sh-ED2003, with sizes ranging from 127 to 183 nm. These NPs were used to stabilize oil-in-water emulsions with isopropyl myristate (IPM). Stability tests revealed that Sh-M600-stabzlized emulsions (up to 40 % oil) remained stable for 6 months, while Sh-ED2003-stabilized emulsions were stable with up to 65 % oil content, even under accelerated conditions. Cryo-SEM imaging confirmed NP accumulation at the oil-water interface, corroborated by reduced interfacial tension in the presence of NP. Adsorption energy calculations demonstrated the superior stabilization capacity of Sh-ED2003 NPs over Sh-M600 NPs. Rheological analysis further supported these findings, showing consistently higher viscosity viscosities for Sh-ED2003-stabilized emulsions across all oil percentages, attributed to the higher molecular weight of its modifier. Collectively, this study demonstrates the effectiveness of tailored shellac NPs in stabilizing robust emulsions, offering potential applications in food, pharmaceuticals, and agriculture.