Abstract: As a purely natural food additive, hawthorn pectin plays an important role in food production and processing. In this experiment, two different drying methods of hot air drying and freeze drying were used to dry hawthorn fruit before powdering by grinding, shearing or air flow, and the thermal properties of the resulting six powders were investigated. Further, pectins were extracted from these samples and their physicochemical properties were compared in terms of galacturonic acid content, total sugar content, esterification degree, Fourier transform infrared spectra, X-ray diffraction patterns and rheological properties. The results showed that there was no significant difference in the thermal characteristics of the hawthorn powders, while the pectin yield and galacturonic acid content in the freeze-dried group were higher than those in the hot-air dried group. Different pulverization methods had no significant effect on the physicochemical properties of hawthorn pectin prepared using the same drying method (P > 0.05). The physicochemical properties of the pectin prepared from the freeze-dried fruit were better than those of the pectin prepared from the hot air-dried fruit using the same pulverization method (P < 0.05).

Key words: hawthorn pectin; physicochemical properties; drying methods; pulverization methods