Analysis of Triglycerides Composition Structure and Physicochemical Properties of Peony Seed Oil

The physical and chemical properties of the peony seed oil, the fatty acid compositions were analyzed by using gas chromatography. The relative content of unsaturated fatty acids was more than 92.00%, mainly consisted of oleic acid(23.92%), linoleic acid(27.58%) and linolenic acid(40.50%). Except free fatty acids, the content of the triglycerides were about 95.89% and the diacylglycerols were about 4.11% in the peony seed oil. By the method of pancreas lipase hydrolysis, the Sn-2 position fatty acids were analyzed and the triglycerides composition of peony seed oil were calculated according to 1,3-random-2-random distribution doctrine. The majority compound in peony seed oil was triacylglycerol which was made up of oleic acid, linoleic acid and linolenic acid. Among them, the content of three unsaturated fatty acid esters was 71.00%, and a saturated and two unsaturated fatty acid ester contents were more than 15.00%. HPLC analysis showed that vitamin E content of the peony oil was 0.56 mg/g). Rancimat determination showed that oxidation stability of the oil was somewhat low(2.85 h at110 ℃).