Nano-encapsulation of catechin in starch nanoparticles: Characterization, release behavior and bioactivity retention during simulated in-vitro digestion

Novel starch-based nanoparticles from three sources: horse chestnut (HSC), water chestnut (WSC) and lotus stem (LSC) were prepared for nano-encapsulation of catechin. Average particle size of HSC, WSC and LSC based nanoparticles were 322.7, 559.2 and 615.6 nm with encapsulation efficiency of 59.09, 48.30, and 55.00% and negative zeta potential of -18.05, -21.5 and -18.05 mv, respectively. Structural, physical and thermal properties were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). SEM revealed capsule formation with entrapped catechin, while broad characteristic peaks at 3475, 1650, 1383, 1148, 1083 and 790 cm(-1) depicts encapsulation of catechin in starch nanoparticles without any evident interaction. XRD showed loss of crystallinity after encapsulation. Higher content of catechin in intestinal juice ensured controlled release in intestine. Bioactive properties were retained at higher level in encapsulated catechin compared to free catechin upon in-vitro digestion.