College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China; Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fuzhou, Fujian, PR China; China-Ireland International Cooperation Centre for Food Material Science and Structure Design, Fujian Agriculture and Forestry University, Fuzhou, PR China.
College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China; Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fuzhou, Fujian, PR China; China-Ireland International Cooperation Centre for Food Material Science and Structure Design, Fujian Agriculture and Forestry University, Fuzhou, PR China.
Ultrason Sonochem. 2020 Nov;68:105199. doi: 10.1016/j.ultsonch.2020.105199. Epub 2020 Jun 1.
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%.
采用超声（超声功率：200 W、600 W、1000 W；时间：5 min、15 min、25 min；固液比（淀粉：缓冲液）：1%、3%、5%）辅助酶解（LS-SNPs 表示经酶解制备的莲子淀粉纳米颗粒，U-LS-SNPs 表示高压匀质辅助酶解制备的莲子淀粉纳米颗粒）制备莲子淀粉纳米颗粒。采用激光粒度分析、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 U-LS-SNPs 的结构和理化性质。扫描电子显微镜结果表明，超声辅助酶解后 U-LS-SNPs 的表面出现开裂和凹凸不平，与 LS-SNPs 相比无明显差异。粒度分析和凝胶渗透色谱结果表明，除 5%处理组外，U-LS-SNPs 的粒径均小于 LS-SNPs。随着超声功率和时间的增加，重均分子量逐渐减小。X 射线衍射和拉曼光谱结果表明，超声首先作用于淀粉颗粒的无定形区。随着超声功率和时间的增加，U-LS-SNPs 的相对结晶度先增加后降低，功率为 600 W、时间为 15 min、固液比为 3%的组相对结晶度最高。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，在超声功率为 600 W、时间为 15 min、固液比为 3%的条件下可制备出粒径较小、结晶度较高的 U-LS-SNPs。
