title: Effect of oil type and fatty acid composition on dynamic and steady shear rheology of vegetable oils.
abstract: 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.
authors.affiliation: Engineering Faculty, Food Engineering Department, Erciyes University, Kayseri, Turkey. hsnyalcin@hotmail.com
authors.forename: Hasan
authors.initials: H
authors.lastname: Yalcin
authors.forename: Omer Said
authors.initials: OS
authors.lastname: Toker
authors.forename: Mahmut
authors.initials: M
authors.lastname: Dogan
mesh_terms: D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry*; D012212:Rheology / Q000379:methods*; D033081:Shear Strength; D014783:Viscosity
chemical_list: D005231:Fatty Acids, Unsaturated; D010938:Plant Oils