Improving the encapsulation efficiency and sustained release behaviour of chitosan/β-lactoglobulin double-coated microparticles by palmitic acid grafting

- Hydrophobic interaction of CS with core material increased by PA grafting.
- Encapsulation efficiency of CS microparticle increased as grafted PA increased.
- Additional βlg layer protected and improved the properties of PA-CS microparticle.
- More sustained release in vitro was achieved in CS microparticle by PA grafting.

Chitosan (CS) was grafted with 0.1 and 0.5% (w/v) palmitic acid (PA) to improve its encapsulation efficiency (EE) and sustained release characteristics when forming CS microparticles. Thereafter, PA-grafted CS (PA-CS) microparticles were coated with denatured β-lactoglobulin (βlg), which forms an outer protective layer. The possibility of hydrophobic interaction with the hydrophobic substances in the CS microparticles increased as the proportion of the grafted PA increased. EE was measured as 64.79, 83.72, and 85.00% for the non-grafted, 0.1, and 0.5% PA-CS microparticles, respectively. In simulated small intestinal conditions, 4.66 and 17.55% of the core material release in the PA-CS microparticles were sustained after 180 min by 0.1, and 0.5% PA grafting, respectively. PA grafting enables the sustained release in simulated gastrointestinal fluids by enhancing the hydrophobic interaction between CS and the hydrophobic core material.