Effect of different phospholipids on the co-encapsulation of curcumin and oligomeric proanthocyanidins in nanoliposomes: Characteristics, physical stability, and in vitro release

In the present study, the differences among NLs prepared with soybean phospholipids (SPL), soybean phosphatidylcholine (PC), and sunflower seed phospholipids (SSPL) were investigated. The structural characteristics, physical stability, in vitro release, and bio-accessibility of NLs co-encapsulating curcumin (Cur) and oligomeric proanthocyanidins (OPC) were evaluated. Compared with PC and SSPL, SPL co-encapsulated Cur and OPC NLs (SPL-co-loaded-NLs) had a smaller particle size (147 nm), a more uniform shape (spherical bilayer structure), and better size homogeneity. In addition, SPL-co-loaded-NLs also possessed the highest stability, antioxidant capacity (DPPH· scavenging rate: 38.79 %, FRAP value: 0.17 mmol Fe 2+ /mL), and bio-accessibility (Cur: 93 %, OPC: 96 %). Furthermore, FT-IR and XRD confirmed that the higher stability of SPL-co-loaded-NLs compared with other NLs was due to their tighter lipid structure, tighter lipid aggregation, and stronger hydrophobic and hydrogen bonding interactions between active substances and phospholipids. This study was expected to provide a theoretical reference for developing functional foods with co-encapsulated active substances of different polarities.