Abstract: By supercritical SAS, we made the resveratrol anti solvent recrystallization to prepare ultrafine resveratrol powder under supercritical condition. The conditions were under 50℃, 20 MPa, resveratrol ethanol solution concentration of 9 mg·mL^-1, and sample solution flow rate of 1 mL·min^-1. We analyzed the particles by Dynamic Light Scattering(DLS) equipment and Scanning Electron Microscopy(SEM). The particle size of the particles was greatly reduced and the average particle size was 0.68±0.03 μm. In addition, characterization of ultrafine Res and raw-resveratrol were tested by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), High performance liquid chromatography(HPLC) and Liquid chromatography-mass spectrometry(LC-MS). SAS process didn't change the chemical structure of Res. The chemical structure of resveratrol was unaffected by the SAS process. The degree of crystallinity of the u-Res particles greatly reduced. We used the purity of the u-Res particles increased from 98.5% to 99.2% during the SAS process. Using drosophila anti-aging experiments to detect the oxidation resistance of resveratrol. The antioxidant capacity of resveratrol powder were higher than that in the second-stage and blank experiment under the concentration of resveratrol solution, 2.5, 5 and 10 mg·mL^-1. The resveratrol had the oxidation resistance, and ultrafine resveratrol powder was better than raw-resveratrol powder.

Key words: ultrafine powder, supercritical antisolvent, micron particl, resveratrol, dissolution rate, antioxidant capacity