β-Lactoglobulin–chlorogenic acid conjugate-based nanoparticles for delivery of (−)-epigallocatechin-3-gallate

Abstract

β-Lactoglobulin (BLG)–chlorogenic acid (CA) conjugates were generated by a free radical induced grafting method. BLG–CA conjugates showed better antioxidant activities than BLG. The antioxidant activity increased with the increase of CA substitution. The particle sizes of (−)-epigallocatechin-3-gallate (EGCG)-loaded nanoparticles prepared by the anti-solvent method were 110.3, 107.4, and 105.8 nm for BLG, BLG–CA (low), and BLG–CA (high), respectively. The encapsulation efficiencies of EGCG in BLG, BLG–CA conjugate (low), and BLG–CA conjugate (high) nanoparticles were 72.9%, 71.8%, and 73.5%, respectively. The chemical stabilities of EGCG in both BLG–CA nanoparticles were significantly higher than in BLG nanoparticles. BLG–CA conjugate (high) showed better EGCG retention than BLG–CA conjugate (low) in simulated gastrointestinal digestion fluid. Little EGCG was released in both BLG nanoparticles and BLG–CA nanoparticles under simulated gastric digestion. The release of EGCG in BLG–CA nanoparticles was less than that in BLG nanoparticles, indicating that CA conjugating protected BLG from the digestive enzymes.