- Conversion of allylic hydroxy oleate to conjugated linoleic acid and methoxy oleate by acid-catalyzed methylation procedures
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Conjugated linoleic acid (CLA), a term describing a group of conjugated octadecadienoic acids that are both naturally occurring and formed during food processing, is the subject of considerable current research because of the recently reported antioxidant and anticarcinogenic properties of these compounds. Allylic hydroxy oleates (AHOs), secondary products of lipid autoxidation, have also been found in foods. By means of high-performance liquid chromatography with ultraviolet detection, gas chromatography/mass spectrometry and gas chromatography/matrix isolation/Fourier transform infrared spectroscopy, we determined that currently used acid-catalyzed methylation procedures convert AHOs to CLA and other products that potentially yield high values in determination of CLA in foods. A mixture of AHOs, containing mainly (8- and 11-)hydroxy-9-octadecadecenoates, was synthesized and tested by methylation procedures with the following catalysts: BF3, HCl, NaOMe and tetramethylguanidine. Both the BF3 and the HCl procedures converted AHOs to CLA. The base-catalyzed procedures did not convert AHOs to CLA.
- Yurawecz,Hood,Roach,Mossoba,Daniels,Ku,Pariza,Chin
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- DIRECT METHOD AND REAGENT KITS FOR FATTY ACID ESTER SYNTHESIS
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Provided are efficient, cost-effective and water tolerant methods (e.g., single-vial methods) for preparing fatty acid esters from organic matter, comprising: obtaining organic matter comprising at least one fat substituent, contacting the organic matter in a reaction mixture with a basic solution under conditions suitable to provide for hydrolytic release of monomeric fatty acids from the at least one fat substituent to provide a base-treated reaction mixture, and esterifying the monomeric fatty acids of the base-treated reaction mixture by acidification of the reaction mixture and treating in the presence of an organic alcohol to provide fatty acid esters. The methods optionally further comprise, prior to esterifying, neutralizing the base-treated reaction mixture to provide for neutralized fatty acids, separating the neutralized fatty acids from the neutralized reaction mixture, and dissolving the separated fatty acids in the esterification reaction mixture. Also provided are related methods and kits for fat analysis.
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Page/Page column 18; 21; 28
(2008/12/07)
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