Effects of Ultrasonic Radiation Treatment and Mechanical Shear Force on the Particle Size and Storage Stability of Chitosan Nanoparticles

• Main Authors: Shi-Wei Bai, 白士緯
• Other Authors: Rong-Huei Chen
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/99784064798238168498

碩士 === 國立臺灣海洋大學 === 食品科學系 === 94 === The objective of the study is to explore the effects of ultrasonic radiation treatment and mechanical shear force during preparation on the particle size and storage stability at 25oC of chitosan nanoparticles prepared by iontotropic gelation with sodium tripolyphosphate. Chitosan was prepared from squid waste by acid and alkali treatment and hot alkali treatment. Degree of deacetylation (DD) of chitosan was 71% detected by Fourier transform infrared spectroscopy and molecular weight of chitosan was 450 kDa detected by high performance size-exclusion chromatography. Particle size of chitosan nanoparticles were measured by light scattering and scanning electron microscope. Storage stability was estimated from the values of changing particle size during storage. In the aspect of ultrasonic radiation conditions during preparation of chitosan nanoparticles, the results showed that increasing the output power, radiation time, solution temperature and solution pH of storage (pH 5.5 to pH 9.9), the mean particle size of chitosan nanoparticles decreased. Most of chitosan nanoparticles prepared by ultrasonic radiation were stable during storage 10 days. In regard to the mechanical shear force treatment conditions during preparation of chitosan nanoparticles, the results revealed that increasing the stirring speed or decreasing the chitosan concentration, the mean particle size of chitosan nanoparticles decreased. The mean particle size of chitosan nanoparticles were the smallest when shearing time was 2 minute or solution temperature was at 45oC or solution pH of storage was pH 11. Most of chitosan nanoparticles prepared by mechanical shear force were unstable and decreased during storage 10 days. Scanning electron microscope graphs showed that chitosan nanoparticles obtained by either the ultrasonic radiation or by the mechanical shear force the chitosan nanoparticles were spherical shape and usually aggregated. The mean particle size of chitosan nanoparticles observed in the SEM graphs were about 100 to 200 nm, similar to the results measured by light scattering.