Fat and fatty acids are extracted from food by hydrolytic methods
(acidic hydrolysis for most products, alkaline hydrolysis for dairy
products, and combination for cheese). Pyrogallic acid is added to
minimize oxidative degradation of fatty acids during anal y sis.
Triglyceride, triundecanoin (C11:0), is added as in ternal standard. Fat
is extracted into ether, then methylated to fatty acid methyl esters
(FAMEs) using BF3 in methanol. FAMEs are quantitatively mea sured
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.