Abstract: This study investigated changes in the physicochemical properties and structural characteristics of oat dietary fiber before and after ultrasonic treatment. Results showed that the water-holding capacity, water-swelling capacity and oil-holding capacity of oat dietary fiber were significantly improved by ultrasonic treatment. Particle size and scanning electron microscopic analysis showed that ultrasonic treatment reduced the particle size and loosened the surface structure, resulting in the appearance of honeycomb-like pores. X-ray diffraction and Fourier transform infrared spectroscopy analysis showed that the relative crystallinity of oat dietary fiber increased after ultrasonic modification, being partially redistributed and transformed into soluble dietary fiber. Differential scanning calorimetry (DSC) analysis showed that the thermal enthalpy (ΔH) of oat dietary fiber significantly increased after ultrasonic modification, indicating its improved thermal stability. Therefore, ultrasonic treatment can be used as an excellent method to modify dietary fiber, which will help to improve the utilization rate of oat dietary fiber and to further explore its nutritional value.

Key words: ultrasound; oat; dietary fiber; physicochemical properties; structure