Yalcin Hasan, Toker Omer Said, Dogan Mahmut
Engineering Faculty, Food Engineering Department, Erciyes University, Kayseri, Turkey.
J Oleo Sci. 2012;61(4):181-7. doi: 10.5650/jos.61.181.
In this study, effect of fatty acid composition on dynamic and steady shear rheology of oils was studied. For this aim, different types of vegetable oils (soybean, sunflower, olive, hazelnut, cottonseed and canola), were used. Rheological properties of oil samples were identified by rheometer (Thermo-Haake) at 25°C and fatty acid composition of oils was determined by GC (Agilent 6890). Steady shear rheological properties of oil samples were measured at shear rate range of 0.1-100 s⁻¹. Viscosity of olive, hazelnut, cottonseed, canola, soybean and sunflower was 61.2 mPa.s, 59.7 mPa.s, 57.3 mPa.s, 53.5 mPa.s, 48.7 mPa.s and 48.2 mPa.s, respectively. There was a significant difference between viscosity of oils except soybean and sunflower. As a result it was seen that there was a correlation between viscosity and monounsaturated (R=0.89), polyunsaturated (R=-0.97) fatty acid composition of oils, separately. Equation was found to predict viscosity of the oils based on mono and polyunsaturation composition of oils. In addition the dynamic rheological properties of oils were also examined. G', G'' and tan δ (G''/G') values were measured at 0.3 Pa (in viscoelastic region) and 0.1-1 Hz. As a result of multiple regression analysis another equations were found between tan δ, viscosity and polyunsaturated fatty acids.
在本研究中，研究了脂肪酸组成对油脂动态和稳态剪切流变学的影响。为此，使用了不同类型的植物油（大豆油、向日葵油、橄榄油、榛子油、棉籽油和菜籽油）。通过流变仪（Thermo-Haake）在25°C下测定油样的流变特性，并通过气相色谱仪（安捷伦6890）测定油的脂肪酸组成。在0.1-100 s⁻¹的剪切速率范围内测量油样的稳态剪切流变特性。橄榄油、榛子油、棉籽油、菜籽油、大豆油和向日葵油的粘度分别为61.2 mPa·s、59.7 mPa·s、57.3 mPa·s、53.5 mPa·s、48.7 mPa·s和48.2 mPa·s。除大豆油和向日葵油外，其他油脂的粘度存在显著差异。结果表明，粘度分别与油中的单不饱和脂肪酸（R=0.89）、多不饱和脂肪酸（R=-0.97）组成之间存在相关性。根据油的单不饱和和多不饱和组成，找到了预测油粘度的方程。此外，还研究了油的动态流变特性。在0.3 Pa（粘弹性区域）和0.1-1 Hz下测量G'、G''和tan δ（G''/G'）值。通过多元回归分析，在tan δ、粘度和多不饱和脂肪酸之间又找到了其他方程。
