BACKGROUND: The positional distribution of the fatty acids on the triacylglycerol influences uptake of calcium, fat, and energy. The positional distribution of breast milk is similar, but not identical, to that of cow and goat milk, and is different to that of vegetable oil. Often, in infant formula a mixture of milk fat with certain vegetable oils is used, to mimic the positional distribution of breast milk. A method for the analysis of fatty acids at the sn-2 position in infant formula and adult/pediatric nutritionals by enzymatic transesterification is presented. OBJECTIVE: The aim of this study is to demonstrate the suitability and applicability of the method to determine fatty acids at the sn-2 position of triacylglycerol molecules in infant formula and adult/pediatric nutritionals by enzymatic transesterification. METHODS: The sample is extracted to isolate the fat, which is treated with a regiospecific enzyme to remove the sn-1(3) positions of the triacylglycerol, resulting in 2-monoacylglycerols. These are then separated using solid phase extraction, transesterified to fatty acid methyl esters, and analyzed using gas chromatography with flame ionization detection. RESULTS: The relative standard deviation repeatability (RSDr) and intermediate precision (RSDiR) were in the range of 1.2-5.2% (RSDr) and 2.0-13.3% (RSDiR). The accuracy was assessed by spiking experiments and model triglycerides, and recoveries were on average 95% (spiked addition) and 97% (model triglycerides). The limit of quantification (LOQ) was found at 0.003 g/100g on reconstituted product. CONCLUSION: The SLV demonstrates that it meets the criteria set in the Standard Method Performance Requirements (SMPRSM) 2022.004. HIGHLIGHTS: A method to determine the content of fatty acids at the sn-2 position by use of an enzyme with good 1(3) regiospecificity was developed. The method complies to international and governmental regulations. The method was evaluated by the Expert Review Panel on Nutrient Methods, and granted first action status.
Holt et al. (Sat,) studied this question.