Fat and fatty acids are extracted from food by hydrolytic meth ods
(acidic hy droly sis for most products, alkaline hy drolysis for dairy
prod ucts, and combination for cheese). Pyrogallic acid is added to
minimize oxidative deg ra da tion of fatty ac ids dur ing anal y sis.
Triglyceride, triundecanoin (C11:0), is added as in ter nal stan dard. Fat
is ex tracted into ether, then meth yl ated to fatty acid methyl es ters
(FAMEs) us ing BF3 in meth a nol. FAMEs are quan titatively measured
by capillary gas chromatography (GC) against C11:0 internal standard.
To tal fat is cal cu lated as sum of in di vid ual fatty ac ids ex pressed as
triglyceride equiv a lents. Sat u rated and monounsaturated fats are
cal cu lated as sum of re spec tive fatty ac ids. Monounsaturated fat
includes only cis form.