Vegetable oils triacylglycerol composition

Overall, DSC is an excellent method to measure the wax appearance and crystallization temperatures of vegetable oils. Due to the complexity of the vegetable oil composition with respect to their FA distribution, the situation is not as simple as pure triacylglycerol molecules. Moreover, there is significant influence of the nature, relative abundance, and orientation of C=C bonds on the wax appearance temperatures. Further, presence of other saturated short-chain-length FAs in vegetable oil structure is found to affect the crystallization process. Statistical analysis of NMR-derived vegetable oil structure support the influence of several predictor variables associated with FA unsaturation on the crystalhzation process. 

Liquid specific heat capacity for fatty acids, triacylglycerols, and vegetable oils was estimated based on their fatty acid composition (Morad et al. 2000). A Rowlinson-Bondi equation was used to estimate specific heat (Cp) for pure fatty acid. The liquid specific heat capacities of oils were estimated by using mixture properties corresponding to the fatty acid composition and a correction factor, which accounts for the TAG form. The Rowlinson-Bondi equation used is as follows ... 

Morad, N.A., Mustafa Kamal, A.A., Panau, F. and Yew, T.W. (2000) Lipid specific heat capacity estimation for fatty acids, triacylglycerols, and vegetable oils based on their fatty acid composition. J. Am. Oil Chem. Soc., 77, 1001-1005. 

Neff, W.E. W.C. Byrdwell G.R. List. A new method to analyze triacylglycerol composition of vegetable oils. Cereal Poods World 2001, 46, 6-10. 

Problem 19.11. Chemical analysis of a typical animal fat or vegetable oil shows the presence of five or more fatty acids. For example, corn oil contains 55 percent linoleic acid, 31 percent oleic acid, 10 percent palmitic acid, 3 percent stearic acid, and 1 percent myristic acid. Explain the meaning of this composition in view of the fact that any triacylglycerol molecule contains only three fatty acid units. 

Fats can be hard and brittle substances (cocoa butter), hard substance (beef tallow), gooey soHds (pork lard, pahn oil) and viscous Hquids (vegetable oils). The melting and soHdihcation points of some fats are Hsted in Table 3.27. The range of values is mainly related to the variabihty of the composition of fatty acids and triacylglycerols. 

Table 4 Triacylglycerol Composition (%) by Carbon Number of Common Vegetable Oils...

Analytical methods for determining the authenticity of vegetable fats have classically been based on comparison of the composition of some major and minor components. For the most important traded oils, tables of the composition (i.e. profiles) of the major fatty acids and sterols have been of importance and have in some cases been supported by data describing other components such as triacylglycerols, sterol esters, volatiles, waxes and fatty alcohols. 

The physical properties of chia oil are similar to perilla and camehna with the same effect of PUFA discussed above. Lipid class composition in chia oil is also typical for vegetable oUs where triacylglycerols are the main components (Table 4)(52). 

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