Fatty acid composition

This method is applicable to infant formula and products related to infant formula, providing that it's preceded by a fat extraction (Bligh-Dyer). The method is used to determine the fatty acid composition in oils and fats. The sample preparation is done according to ISO 12966-2 2017 (chapter 4.4). For the calculation of the fatty acid composition, internal standards are used as mentioned in ISO 16958 2015.

The sample is reconstituted with water to ensure homogeneity. The fat is extracted with methanol and chloroform. An aliquot of this organic layer is evaporated until only the fat remains. An aliquot of this fat is then weighed into a vail and the vial is capped. Internal standard, recovery solution are added by an automated process, followed by a solution of sodium hydroxide in methanol. The triacylglycerides (TAG) are converted to FAMEs under the influence of this alkaline catalyst. The FAMEs that are formed are extracted with iso octane, diluted and then analysed using GC-FID (conform ISO EN14103). The FAMEs are quantified by using an internal standard (C11:0 FAME). The recovery of C13:0 triacylglycerol (TAG) is checked to monitor the transesterification.