Abstract: The peel and pomace of Jincheng sweet oranges were used to prepare dietary fiber (DF). Ordinary and micronized DF powders were obtained using a multi-purpose grinder and a planetary ball mill, respectively. The physicochemical properties and heavy metal adsorption abilities of the DF powders were measured. A Laser particle analyzer, an infrared spectrometer, an X-diffractometer, a thermal analyzer, and a scanning electron microscope were used for particle size measurement and microstructural observation. Our aim was to evaluate the effect of micronization of sweet orange DF on its physicochemical properties, microstructure and heavy metal adsorption ability. Compared with the ordinary powder, the micronized powder had a smaller particle size as well as a lighter color and showed a significant increase in water retention capacity, oil retention capacity, swelling capacity, and adsorption ability toward heavy metal ions (P < 0.05). This experiment provides a theoretical basis for the comprehensive utilization of Jincheng organ peel and pomace as a potential source of food additive.

Key words: peel and pomace, dietary fiber, micronization, functional properties