Delivery of curcumin by shellac encapsulation: Stability, bioaccessibility, freeze-dried redispersibility, and solubilization
Yongkai Yuan, Shuaizhong Zhang, Mengjie Ma, Ying Xu, Dongfeng Wang
Abstract
Curcumin is an active ingredient with multiple functions, however, its application is limited by its low stability, bioaccessibility, freeze-dried redispersibility, and solubilization. The work aims to improve the application of curcumin (Cur) by encapsulation. Shellac was the wall material inspired by its pH-dependent deprotonation and amphiphilic nature to form nanoparticles. The curcumin/shellac nanoparticles (S/Cur) exhibited a bright spot of high loading capacity (the maximum of higher than 70 %), while still having high encapsulation efficiency (the minimum of higher than 85 %). Transmission electron microscopy showed that S/Cur was a spherical structure. It exhibited good physical stability, including pH (4.0-8.0), ionic strength (NaCl, < 900 mM), thermo stability (80 ℃, 180 min), and storage stability (light and dark, 4 and 25 ℃, 20 days). Meanwhile, the chemical stability was increased by encapsulation. Furthermore, the bioaccessibility of Cur was improved to 75.95 %, which is attributed to the pH response of shellac. Additionally, S/Cur had freeze-dried redispersibility and solubilization, which is proportional to the mass ratio of shellac-to-Cur. The mechanism of S/Cur formation involved hydrophobic interaction and hydrogen bonds, and the nanoconfined Cur was amorphous.