Abstract:To established extraction methods and exploring the structure and physicochemical properties of dietary fiber from Annona squamosa Pulp，the ultrasound-assisted enzymatic method was used to extract soluble dietary fiber from Annona squamosa Pulp （AP-SDF）. The factors influencing the yield of AP-SDF，such as ultrasound time，dosage of thermostable α-amylase，dosage of alkaline protease，and water bath time were investigated，and the process conditions were optimized by single-factor test and orthogonal test. In addition，X-ray diffraction，Fourier transform infrared spectrum，and other technologies were employed to reveal the structure and physicochemical properties of AP-SDF. The result showed that the optimized extraction conditions for AP-SDF were ultrasound time of 30 min，3% dosage of thermostable α-amylase，1.0% dosage of alkaline protease，and water bath time of 60 min. Under these conditions，the yield of AP-SDF was （15.78±0.37）%. AP-SDF contained active functional groups such as carboxyl，hydroxyl，and aldehyde groups. It had a low crystallinity and a soft texture，which was conducive to improving hydration performance. It showed strong water-holding capacity，oil-holding capacity，and expansion capacity，serving as a high-quality dietary fiber and exhibiting great development value.