Hydrophobic linoleic acid–modified chitosan: Potential as a nanoemulsifier

In this study, a positively charged emulsifier was developed by hydrophobic modification of chitosan with linoleic acid (LA), and a 5 % LA grafting degree was subsequently confirmed by TLC, ¹H NMR, and DOSY measurements. The emulsifying ability of chitosan was markedly improved by LA modification, which allowed the preparation of a stable nanoemulsion at more than 0.5 % (w/w) emulsifier concentration after 5–10 microfluidization passes. Under these conditions, the LA-chitosan stabilized emulsion exhibited a unimodal nanoscale droplet size distribution and remained creaming-free during 29 days of storage. Compared with SDS -stabilized nanoemulsions, which exhibited significant destabilization in the presence of positively charged proteins, the LA–chitosan-stabilized nanoemulsions maintained high stability. The results suggest that LA-chitosan has potential for use as a food-grade emulsifier for the formulation of stable nanoemulsions.