Submitted to: Grasas Y Aceites Monograph
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 8, 2003
Publication Date: January 20, 2004
Citation: List, G.R., Adlof, R.O., Carriere, C.J., Dunn, R.O. 2004. Melting properties of some structured lipids native to high stearic acid soybean oil. Grasas Y Aceites Monograph. 2:135-137. Interpretive Summary: Fats used in food products such as margarines and shortenings usually melt over a wide range because they are formulated for functional purposes including spreadability, resistance to oil loss, sensory attributes or the ability to incorporate air into baked goods. This paper describes the physical properties of some pure fatty compounds found in natural fats and oils.
Technical Abstract: A number of structured lipids native to high stearic acid soybean oil were synthesized and their physical properties determined by pulsed nuclear magnetic resonance (NMR), Mettler dropping point and differential scanning calorimetry (DSC). 1,3 Distearo-2-olein (SOS), 1,3 distearo-2-linolein (SLS) and 1,3 distearo-2-linolenin (SlnS) were synthesized from pure 1,3 diacylglycerols and the appropriate fatty acid. Pulsed NMR determinations over the temperature range 10-50 degrees C showed that the symmetrical triacylglycerols (SUS: where S = stearic, U = oleic, linoleic or linolenic) are high and sharply melting materials, all showing high amounts of solids at temperatures up to 33.3 degrees C, yet are completely melted at only a few degrees higher. Mettler dropping points for SOS, SLS and SlnS were 44.1, 37.9 and 36.5 degrees C respectively. Heats of fusion for the structured triacylglycerols were determined by DSC and shown to be of the order 29-32 cal/gm compared to 45 cal/gm for SSS. Heats of fusion were also calculated from Mettler dropping point determinations as admixtures with soybean oil and showed good agreement with the DSC data.