Highly stable whey protein-based nanocapsule prepared by in-situ crosslinking in Pickering emulsion

Protein-based carriers contribute to encapsulating oil-soluble bioactive compounds; however, their environmental stability is concerned in further application, especially, under thermal variation. In this work, a novel method for the delivery of oil-soluble bioactive compounds was developed using food-grade whey protein-based crosslinked nanocapsules (PCCs). Whey protein crosslinked emulsions (PCEs) were prepared from whey protein-stabilized Pickering emulsions (PUEs) through transglutaminase stimulated crosslinking. PCEs maintained a smooth spherical morphology after redispersion. The influence of droplet size and emulsion state of PCEs and PUEs upon freeze-thaw, heat and ionic strengths treatment were investigated via DLS characterization and microscope observation. The PCCs presented high drug encapsulation efficiency (96.14 %) and loading capacity (36.92 %). The in-situ crosslinking treatment rendered PCEs stable structure and therefore protective performance for sensitive ingredients such as phenylethyl resorcinol (PR). The prepared PCEs showed improved retention of PR under light, thermal and freeze-heat. PCEs also retained typical sustained in vitro drug-release and skin permeation behavior as PUEs. These findings indicate that PCEs are a useful carrier to package phenylethyl resorcinol and similar compounds in cosmetic products.