Synthesis and characterization of enzymatically cross-linked feruloyl amylopectin for curcumin encapsulation

Feruloyl amylopectin (FAP) was synthesized by the N,N′-carbonyldiimidazole (CDI) activation method, and the enzymatically cross-linked feruloyl amylopectin (CL-FAP) was prepared via catalysis of horseradish peroxidase (HRP) with the presence of hydrogen peroxide (H2O2). RP-HPLC-DAD/ESI-TOF-MS measured ferulic acid and its derivatives in FAP and CL-FAP. FAP was primarily composed of two ferulate monomers, while CL-FAP was composed of two ferulate monomers and two ferulate dehydrodimers. The ester formation in the feruloyl group was confirmed by the presence of carbonyl and aromatic CC signal near 1725 (1723) and 1510 cm−1 in the FT-IR spectra. X-ray diffraction studies showed that the two modified amylopectins lost the ordered A-type crystalline structure, characteristic of maize amylopectin. The encapsulation capacity of curcumin (ECC) in 1 mg/mL CL-FAP microemulsion was measured at 88.13 μg/mg by HPLC.