Analysis of Monoglycerides, Diglycerides, Sterols, and Free Fatty Acids in Coconut (Cocos nucifera L.) Oil by 31P NMR Spectroscopy

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• 作者：Fabian M. Dayrit ; Olivia Erin M. Buenafe ; Edward T. Chainani ; Ian Mitchelle S. de Vera
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2008
• 出版时间：July 23, 2008
• 年：2008
• 卷：56
• 期：14
• 页码：5765 - 5769
• 全文大小：1113K
• 年卷期：v.56,no.14(July 23, 2008)
• ISSN：1520-5118

文摘

Phosphorus-31 nuclear magnetic resonance spectroscopy (³¹P NMR) was used to differentiate virgin coconut oil (VCO) from refined, bleached, deodorized coconut oil (RCO). Monoglycerides (MGs), diglycerides (DGs), sterols, and free fatty acids (FFAs) in VCO and RCO were converted into dioxaphospholane derivatives and analyzed by ³¹P NMR. On the average, 1-MG was found to be higher in VCO (0.027%) than RCO (0.019%). 2-MG was not detected in any of the samples down to a detection limit of 0.014%. On the average, total DGs were lower in VCO (1.55%) than RCO (4.10%). When plotted in terms of the ratio [1,2-DG/total DGs] versus total DGs, VCO and RCO samples grouped separately. Total sterols were higher in VCO (0.096%) compared with RCO (0.032%), and the FFA content was 8 times higher in VCO than RCO (0.127% vs 0.015%). FFA determination by ³¹P NMR and titration gave comparable results. Principal components analysis shows that the 1,2-DG, 1,3-DG, and FFAs are the most important parameters for differentiating VCO from RCO.