Lotus seed starch nanoparticles were prepared by ultrasonic (ultrasonic power: 200 W, 600 W, 1000 W; time: 5 min, 15 min, 25 min; liquid ratio (starch: buffer solution): 1%, 3%, 5%) assisted enzymatic hydrolysis (LS-SNPs represent lotus seed starch nanoparticles prepared by enzymatic hydrolysis and U-LS-SNPs represent lotus seed starch nanoparticles prepared by high pressure homogenization-assisted enzymatic hydrolysis). The structure and physicochemical properties of U-LS-SNPs were studied by laser particle size analysis, scanning electron microscope, X-ray diffraction, Raman spectroscopy, nuclear magnetic resonance and gel permeation chromatography system. The results of scanning electron microscopy showed that the surface of U-LS-SNPs was cracked and uneven after ultrasonic-assisted enzymolysis, and there was no significant difference from LS-SNPs. The results of particle size analysis and gel permeation chromatography showed that the particle size of U-LS-SNPs (except 5% treatment group) was smaller than that of LS-SNPs. With the increase of ultrasonic power and time, the weight average molecular gradually decreased. The results of X-ray diffraction and Raman spectroscopy showed that ultrasonic waves first acted on the amorphous region of starch granules. With the increase of ultrasonic power and time, the relative crystallinity of U-LS-SNPs increased first and then decreased. The group (600 W, 15 min, 3%) had the highest relative crystallinity. The results of nuclear magnetic resonance studies showed that the hydrogen bond and double helix structure of starch were destroyed by ultrasound, and the double helix structure strength of U-LS-SNPs was weakened compared with LS-SNPs. In summary, U-LS-SNPs with the small-sized and the highest crystallinity can be prepared under the conditions of ultrasonic power of 600 W, time of 15 min and material-liquid ratio of 3%.

通过超声（超声波功率：200 W，600 W，1000 W；时间：5分钟，15分钟，25分钟；液比（淀粉：缓冲溶液）：1％，3％，5％）制备莲子淀粉纳米颗粒。辅助酶解（LS-SNPs代表通过酶促水解制备的莲子淀粉纳米颗粒，U-LS-SNPs代表通过高压均质化辅助酶促水解制备的莲子淀粉纳米颗粒）。通过激光粒度分析，扫描电子显微镜，X射线衍射，拉曼光谱，核磁共振和凝胶渗透色谱系统研究了U-LS-SNPs的结构和理化性质。扫描电镜观察结果表明，超声辅助酶解后，U-LS-SNPs表面裂纹不平整，与LS-SNPs没有显着差异。粒度分析和凝胶渗透色谱法的结果表明，U-LS-SNPs（5％处理组除外）的粒度小于LS-SNPs。随着超声功率和时间的增加，重均分子逐渐减小。X射线衍射和拉曼光谱的结果表明，超声波首先作用于淀粉颗粒的无定形区域。随着超声功率和时间的增加，U-LS-SNPs的相对结晶度先升高后降低。该组（600 W，15分钟，3％）具有最高的相对结晶度。核磁共振研究结果表明，超声破坏了淀粉的氢键和双螺旋结构，与LS-SNPs相比，U-LS-SNPs的双螺旋结构强度减弱。综上所述，可以在600 W的超声功率，15 min的时间和3％的料液比的条件下制备尺寸小，结晶度最高的U-LS-SNPs。