High resveratrol-loaded microcapsules with trehalose and OSA starch as the wall materials: Fabrication, characterization, and evaluation

To improve the solubility and stability of resveratrol (Res), Res nanocrystals (Res-ncs) as the capsule core were prepared by wet milling using hydroxypropyl methyl cellulose (HPMCE5), sodium dodecyl sulfate (SDS), and polyvinylpyrrolidone (PVPK30) as stabilizers, along with trehalose and octenyl succinic anhydride (OSA) modified starch were used as the wall material to produce Res microcapsules (Res-mcs) via spray drying. The fresh-prepared Res-ncs and rehydrated Res-mcs had mean particle sizes of 190.30 ± 3.43 and 204.70 ± 3.60 nm, zeta potentials of −13.90 ± 0.28 and − 11.20 ± 0.34 mV, and the loading capacities (LC) were as high as 73.03 % and 28.83 %. Particle morphology showed that Res-mcs had more regular and smooth spherical structures. FTIR indicated that Res may have hydrogen bonding with the walls. XRD and DSC exhibited that Res in nanocrystals and microcapsules existed mostly as amorphous structures. The solubility of Res-mcs and Res-ncs was increased, with excellent redispersibility and rapid dissolution of Res in vitro. The antioxidant properties of Res-mcs were protected and improved. With the walls acting as a physical barrier, Res-mcs have better photothermal stability than raw Res. Res-mcs have a relative bioavailability of 171.25 %, which is higher than that of raw Res.