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タイトル: ショ糖ステアリン酸エステルが形成する一時的ネットワーク構造
著者: 髙橋, 沙央里
タカハシ, サオリ
発行日: 11-Jun-2014
抄録: The rheological properties and structure of the sucrose stearate molecular assemblies were investigated. Sucrose stearate is a one of the edible nonionic surfactants. The steady state viscosity and the dynamic modulus were measured as rheological properties of sucrose stearate aqueous solution. To investigate the microscopic structure of the molecular assemblies, a homemade small-angle light scat tering apparatus was build. The sample of sucrose stearate used in this study was an industrial grad, Ryoto Sugar Ester S-1670 (Mitsubishi Kagaku Foods Co. Ltd ., Tokyo, Japan) The outlook of the samples ( 1 to 8 wt%) was translucent or turbid from 20 to 47 ;however, it became transparent above 48℃ and their viscosity increased. The viscosity began to rise from 40℃ around aqueous solution at 3 to 8 wt%. The maximum viscosity value appeared a t 48℃ around. To obtain information on the structure of the molecular assembly, an SALS study was conducted. We can see strong scattering intensity at the low q region below the critical temperature (48℃); however, the scattering intensity was reduced above the critical temperature. We calculate the characteristic length of the density fluctuations from the scattering profile. The estimated values of ξ from the scattering profile were 300nm, 564nm and 862nm for 40℃ , 45℃ and 47℃ , respectively. These results indicates that relatively large molecular assemblies existed in the turbid phase; however, the size of the molecular assemblies decreased at approximately 48℃. In steady viscous flow measurements, viscosity was the maximum near 47℃. In measurement of frequency dependence of dynamic modulus of elasticity, the analysis in the Maxwell model was possible from 48℃ to 50℃. Scaling factor w as G_<tot> ∝ C^<1.9>. This result shows that stress under deformation occurred from the entanglement of the thread-like molecular assembly. According to reputation theory, when increase in concentration, worm-like micelles gets longer and the relaxation time gets longer. Since there is no strong dependence to the concentration relationship of concentration and slow mode relaxation time (τ_s), it is considered that the theory dose not work in this case. The mechanism of mechanical relaxation in this study can be explained by a phantom network model. It was revealed that Cox-Mertz rule has collapsed at around a critical shear rate, which was shear thinning beginning point in the flow curve. It is considered that the structure was destroyed by deforming at a faster rate than the relaxation time measured in the linear region, and there fore the stress has been reduced drastically. It is considered that structure was transition at 48℃ by a change in hydration behavior for SE18 aqueous solutions. Although the details of SE18 molecular assemblies below 48℃, it is considered that small structures such as spherical micelles are formed at around 30℃, and large aggregates had been formed in 40℃ or more.
URI: http://hdl.handle.net/10659/3412
学位授与年月日: 2013
学位名: 食品栄養科学
学位授与機関: 酪農学園大学
出現コレクション:学位論文(修士)

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