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United States Department of Agriculture

Agricultural Research Service

Title: Seperation of the Molecular Species of Acylglycerols

Authors
item Lin, Jiann-Tsyh
item McKeon, Thomas

Submitted to: Meeting Abstract
Publication Type: Book / Chapter
Publication Acceptance Date: September 30, 2004
Publication Date: April 30, 2005
Citation: Lin, J.T., Mckeon, T.A. 2005. Seperation of the molecular species of acylglycerols. Meeting Abstract. pp. 1-16

Interpretive Summary: Ricinoleate (a hydroxy fatty acid) has many industrial uses such as the manufacture of aviation lubricant, plastics, paints, coatings and cosmetics. Its only commercial source is castor bean. Since castor bean contains the toxin ricin as well as potent allergens, it is hazardous to grow, harvest and process. It would be desirable to produce ricinoleate instead in a transgenic oilseed lacking these toxic components. We have recently reported the biosynthetic pathway of castor oil and identified the key enzymatic steps, which drive ricinoleate into castor oil in castor bean. We have also identified and quantified molecular species of acylglycerols incorporated from various radiolabeled fatty acids using high-performance liquid chromatography (HPLC). Since acylglycerols are the major component of oil and fat, and are important in medicine, industry and biotechnology, we review here the HPLC of the molecular species of acylglycerols.

Technical Abstract: Many non-aqueous gradient reversed-phase C18 HPLC systems have been developed for the separations of the molecular species of triacylglycerol (TAG) and diacylglycerols (DAG) in natural oils. The elution orders of the molecular species of TAG and DAG depend on the polarity of their FA constituents with elution time increasing as polarity decreases. The elution orders depending on their FA constituents were as follows: ricinoleic acid < linolenic acid < palmitoleic acid < myristic acid < palmitelaidic acid < linoleic acid < linolelaidic acid < oleic acid < palmitic acid < elaidic acid < petroselinic acid < petroselaidic acid < stearic acid. The elution corresponded closely with chain length, degree of unsaturation and presence of polar group and they were similar to the elution orders of FA in the aqueous C18 HPLC system. The configuration and location of double bond on acyl chain and stereospecific location of FA on glycerol backbone affect slightly on the retention times. Equivalent carbon number method has been used mostly for the designation of the HPLC peaks. The relative retention time prediction method of the C18 HPLC using the linear gradient eluent of methanol/2-propanol we developed can also be used for the designation, including the designation of the peaks from flow scintillation analyzer in metabolic study.

Last Modified: 12/19/2014
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