title: Effect of ultrasonic treatments on nanoparticle preparation of acid-hydrolyzed waxy maize starch.
abstract: Waxy maize starch was dispersed (14.7% solids) in an aqueous sulfuric acid solution (3.16M), and hydrolyzed by stirring for up to 7 days at 40°C with ultrasonic treatments at different vibration amplitudes (20 and 40%) and durations (30 and 60min/day). The amount of starch nanoparticles in the hydrolyzates isolated after 7 days, measured by a dynamic light scattering detector, was raised from 20% to 70% by an ultrasonic treatment (20% amplitude, 30min). The aggregation of nanoparticles possibly occurring during the hydrolysis was effectively prevented by the ultrasonication. Alternatively, ultrasonic treatments were applied to the re-dispersed suspension of the large microparticles of starch hydrolyzates (2 days) precipitated by a mild centrifugation (500rpm, 10min). By an ultrasonic treatment at 60% vibration amplitude for 3min, the microparticles could be completely transformed to nanoparticles. The inherent crystalline structure of waxy maize starch (A-type in X-ray diffraction) remained after the ultrasonic treatments during acid hydrolysis, but it was disrupted by the ultrasonic treatments for the re-dispersed microparticles.
authors.affiliation: Graduate School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Hee-Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Jung-Ah
authors.initials: JA
authors.lastname: Han
authors.forename: Dong-Keon
authors.initials: DK
authors.lastname: Kweon
authors.forename: Jong-Dae
authors.initials: JD
authors.lastname: Park
authors.forename: Seung-Taik
authors.initials: ST
authors.lastname: Lim
mesh_terms: D000143:Acids / Q000737:chemistry; D003460:Crystallization; D057446:Hydrodynamics; D006868:Hydrolysis; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013213:Starch / Q000737:chemistry* / Q000648:ultrastructure; D013535:Suspensions / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D014465:Ultrasonics / Q000379:methods*; D014961:X-Ray Diffraction; D003313:Zea mays / Q000737:chemistry*
chemical_list: D000143:Acids; D013535:Suspensions; D013213:Starch