Nuclear magnetic resonance and gas chromatography mass spectroscopy analysis of the nonvolatile components produced during heating of oleic acid esterified propoxylated glycerol, a fat substitute model compound, and trioleylglycerol

Oleic acid esterified propoxylated glycerol (EPG-08 oleate) and trioleylglycerol were heated separately (192 +/- 8 degrees C for 12 h/day) until the polymer content was greater than or equal to 20% and examined. Supercritical fluid fractionation (SFF) produced a monomer fraction of 98.3% purity and a dimer fraction of 90.8% purity for heated EPG-08 oleate and comparable fractions for triolein. Carbon-13 NMR analysis of the fractionated dimer (SFF-D) oil samples indicated peaks at approximately 107-108, 67-68, and 23.8 ppm that were present in only the SFF-D samples. The presence of these peaks in both samples indicated that the presence of the oxypropylene backbone was not necessary for the formation of the bonds corresponding to these peaks. The oxypropylene backbone profile was the same for the day 0 and the SFF-D sample. Gas chromatography/mass spectrometry of dimeric fatty acid methyl esters indicated that the fatty acid portion of the molecule was involved in dimer formation for both oil samples.