Effects of different drying and milling methods on the physicochemical properties and phenolic content of hawthorn fruit powders

This study aims to obtain the physicochemical properties of hawthorn fruit powder produced using different methods. Two drying methods, hot-air drying and freeze-drying, and three grinding methods, mortar grinding, shear pulverization, and jet milling, were applied to obtain the hawthorn fruit powders. The physicochemical properties of the six powders were compared using scanning electron microscopy, X-ray diffraction (XRD) analysis, and differential scanning calorimetry. The phenolic content analyses were performed using EIS-MS2 high-pressure liquid chromatography. The results showed that freeze-drying and shear pulverization yielded higher content of cyanidin-3-galactoside content. Freeze-drying and jet milling were the most effective for reduction of the hawthorn fruit powder particle size (D50 value 27.81 mu m); a higher water solubility index; higher phenolic content, such as chlorogenic acid and hyperoside; and a more natural color, all of which made the powder better for application in functional foods. Different drying and grinding methods did not change the crystal structure of the hawthorn fruit powder fiber. As a result, the superfine grinding of hawthorn fruit powders could be a promising process in manufacturing instant and convenient foods, as well as active pharmaceutical ingredients. Practical applications Superfine grinding is a new technology that can yield powder with excellent surface properties. Ultrafine powder has unique physical and chemical properties, such as good solubility, dispersion, adsorption, and chemical activity, and is an ideal means of food processing. Hot-air drying in combination with jet milling can significantly improve the fluidity of the powder. However, freeze-drying in combination with jet milling results in a higher water solubility index (WSI), procyanidin B2, and chlorogenic acid content, and a more uniform and nonseparable mixture. Freeze-dried powders have smaller particle sizes and larger specific surface areas than hot-air-dried powders. The superfine grinding of hawthorn fruit powders could be a promising process in manufacturing instant and convenient foods, as well as active the pharmaceutical ingredients.