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United States Department of Agriculture

Agricultural Research Service

Title: Synthesis and Physical Properties of Some Symmetrical Disaturated Monounsaturated Triacylglycerols and Their Functional Roles in Food Oil Systems

item List, Gary
item Steidley, Kevin
item Adlof, Richard

Submitted to: Oilseed Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 23, 2000
Publication Date: N/A

Technical Abstract: Symmetrical SUS triacylglycerols (TAGs), where S = saturated fatty acids (stearic (S)) and U = unsaturated fatty acids (oleic (O), linoleic (L), or linolenic (Ln)), were synthesized and their physical properties determined. The reaction sequence consisted of stearic acid transesterified to tristearin, followed by conversion of the TAG to a mixture of 1,3 and 1,2 diacylglycerols (DAGs) isolated and purified by crystallization and column chromatography. The pure 1,3 DAGs were then esterified with the appropriate fatty acid to form the symmetrical TAGs. SOS was 98.4% pure while the SLS and SLnS were 100% pure when analyzed by high pressure liquid chromatography (HPLC). The solid fat content (SFC) of the TAGs was determined by pulsed nuclear magnetic resonance spectroscopy over a temp range of 10-50C. Symmetrical disaturated TAGs are high, yet sharp melting compounds. For example, SOS, SLS and SLnS show high solids at temps of 30-35C, yet are completely melted at temps only a few degrees higher. The drop melting points for SOS, SLS and SLnS were 44.1, 37.9 and 36.5C respectively. Studies made on admixtures of the symmetrical SUS TAGs with soybean oil show typical linear SFC profiles, much like those observed with hydrogenated basestock/liquid oil blends used for margarine/spread formulations. Symmetrical disaturated TAGs are important components providing functionality to interesterified fat blends and structurally modified oils obtained by plant breeding since their high melting properties provide needed functionality at 10 and 21.1C (spreadability, resistance to water/oil loss at room temp) while their sharply melting characteristics provide mouth feel and quick flavor release at body temp.

Last Modified: 3/26/2015
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