Abstract:To investigate the effect of superfine grinding on powder characteristics and active components of Prunus mira Koehne, freeze-drying combined with coarse grinding (3 min) and superfine grinding (5, 10 and 15 min, respectively) were employed to prepare the powder of Prunus mira Koehne. The powder characteristics (including particle size, microstructure, flowability and hygroscopicity) and the contents and antioxidant capacity of active components (including polyphenol, polysaccharide and water soluble pectin) of Prunus mira Koehne powder were determined. Results showed that with increasing superfine grinding time, the particle size of Prunus mira Koehne powder became smaller than coarse powder, and the size distribution span decreased from 6.58±0.54 to 2.86±0.09. A significant decline in the compressibility was observed, while both bulk density and basic fluidity energy increased. Superfine grinding technology could improve hydration characteristics of the powder. When relative humidity was less than 50%, the powder hygroscopicity had no significant change. The antioxidant activity of polyphenol and polysaccharide extracted from Prunus mira Koehne powder prepared by superfine grinding technology show no significant difference. Content of water soluble pectin extracted from Prunus mira Koehne powder was decreased, however, its antioxidant activity was significantly increased (p<0.05). Therefore, the superfine grinding technology could be a deep processing method to improve the quality of Prunus mira Koehne powder and preserve its active components.
