Dear All If we look at AOAC Official Method 963.22 which is most commonly follwed method -two things are very clear. one - in the process of methyl ester formation free fatty acids as well as fatty acids in tri acyl glycerol or in membrane lipids are all esterified. two- sum area under different fatty acids peaks in chromatogram is taken 100 so fatty acid amount in a particular food sample is a per cent proprtion of total fatty acids. Hence, results are in percent fatty acids and not affected by methyl or butyl esterification. Dr. Rakesh Bhardwaj Senior Scientist (Biochemistry) Germplasm Evaluation Division National Bureau of Plant Genetic Resources (NBPGR) PUSA Campus, New Delhi - 110 012 India Phone (+91)11-25848074(O),(+91)11-25842495(Fax) (+91)9560487889 (M), (+91) 9015405449 --- On Thu, 4/4/13, Elizabeth Lund <[log in to unmask]> wrote: From: Elizabeth Lund <[log in to unmask]> Subject: Re: non-esterified fatty acid concentration To: [log in to unmask] Date: Thursday, April 4, 2013, 5:34 AM Dear All, When analysing fatty acid composition of foods it is normal to hydrolyse the fatty acids from the glycerol as occurs in the gut. I do not see the relevance of free fatty acids per se in food. In people it is a different matter. Elizabeth Lund Independent Consultant Nutrition and Gastrointestinal Health Tel. +441508488049 Mob. +447841529097 http://www.elizabethlund.co.uk From: Anders Møller <[log in to unmask]> Organization: Danish Food Information Reply-To: <[log in to unmask]> Date: Thursday, 4 April 2013 08:29 To: <[log in to unmask]> Subject: Re: non-esterified fatty acid concentration Dear David, Isn’t that the information we carry in almost all food composition databases/tables? We recalculate the analysed methyl (or butyl) ester concentrations of fatty acids to express the data as “free” or non-esterified fatty acids? If not, could you then elaborate a little on what is then meant? All the best, Anders Anders Møller Danish Food Information Borgediget 12 DK-4000 Roskilde, Denmark Websites: Danish Food Information (http://www.danfood.info) SciName Finder™ (http://www.sciname.info) LanguaL™ (http://www.langual.org) From: Food Composition Discussion Group [mailto:[log in to unmask]] On Behalf Of Haytowitz, David Sent: 03 April 2013 23:36 To: [log in to unmask] Subject: non-esterified fatty acid concentration Hello: We got a request asking if we had anything on the non-esterified fatty acid concentration of foods. Also, if anyone is working in this area. Thank you, David ******************************************************************** * David B. Haytowitz * U.S. Department of Agriculture * * 10300 Baltimore Avenue * Agricultural Research Service * * B-005, Rm. 207A, BARC-West * Beltsville Human Nutrition * * Beltsville, MD 20705 * Research Center * * 301-504-0714 * Nutrient Data Laboratory * * 301-504-0713 FAX * EMAIL: [log in to unmask] * ********************************************************************* This electronic message contains information generated by the USDA solely for the intended recipients. Any unauthorized interception of this message or the use or disclosure of the information it contains may violate the law and subject the violator to civil or criminal penalties. If you believe you have received this message in error, please notify the sender and delete the email immediately. To unsubscribe from the InFoods-Food-Comp-L list, click the following link: https://listserv.fao.org/cgi-bin/wa?SUBED1=InFoods-Food-Comp-L&A=1 To unsubscribe from the InFoods-Food-Comp-L list, click the following link: https://listserv.fao.org/cgi-bin/wa?SUBED1=InFoods-Food-Comp-L&A=1 To unsubscribe from the InFoods-Food-Comp-L list, click the following link: https://listserv.fao.org/cgi-bin/wa?SUBED1=InFoods-Food-Comp-L&A=1 ######################################################################## To unsubscribe from the InFoods-Food-Comp-L list, click the following link: https://listserv.fao.org/cgi-bin/wa?SUBED1=InFoods-Food-Comp-L&A=1