Formation, stability and in vitro digestion of curcumin loaded whey protein/ hyaluronic acid nanoparticles: Ethanol desolvation vs. pH-shifting method.

Curcumin (CUR) was encapsulated in whey protein isolate/hyaluronic acid (WPI/HA) electrostatic nanoparticles at pH 5.4, 4.4, 3.4 and 2.4 using ethanol desolvation (DNP) or pH-shifting (PSNP) method. The prepared nanoparticles were characterized and compared for physiochemical properties, structure, stability, and in vitro digestion. PSNPs had smaller particle size, more uniform distribution, and higher encapsulation efficiency than DNPs. Main driving forces involved for fabricating the nanoparticles were electrostatic forces, hydrophobic forces, and hydrogen bonds. PSNP exhibited better resistance towards salt, thermal treatment, and long-term storage while DNPs showed stronger protection for CUR against thermal degradation and photodegradation. Stability of nanoparticles increased with decreasing pH values. In vitro simulated digestion exhibited that DNPs had lower release rate of CUR in SGF and higher antioxidant activity of its digestion products. Data may provide a comprehensive reference for selection of loading approach when constructing nanoparticles based on proteins/polysaccharides electrostatic complexes.