Development of curcumin loaded core-shell zein microparticles stabilized by cellulose nanocrystals and whey protein...

Novel multilayered core-shell microparticles were developed to deliver curcumin using positively charged zein microparticles coated with negatively charged cellulose nanocrystals (CNCs) and positively charged whey protein microgels (WPMs) at pH 4. Different levels of WPMs (0.10%-1.50%, w/v) were utilized to regulate the structure, stability, and in vitro digestion of curcumin loaded zein-CNC core-shell microparticles. The size of zein-CNC-WPM core-shell microparticles ranged from 2087.7 to 2928.2 nm. The electrostatic attraction and hydrogen bonding were mainly involved in the assembly of the core-shell microparticles through particle-particle interactions. The microstructure of the core-shell microparticles was dependent on the level of the WPM. When its appropriate level was adopted (0.50%-1.00%, w/v), the WPM formed a protective shell for zein-CNC-WPM core-shell microparticles. The retention rate of curcumin in the core-shell microparticles increased by 47.56% and 32.79% during light and thermal treatment, respectively. Excess microgels facilitated the bridging aggregation and formation of a network structure on the particle surface, which further reduced their stability and greatly restricted the curcumin release. The potential of nanosized protein microgels was explored to stabilize and modulate the physicochemical properties of multilayered core-shell microparticles through interparticle interactions.