Application of a HRGC method on capillary column Rtx 65-TG for triglyceride analysis to monitor butter purity.

In this article a new analytical method is proposed for the detection of extraneous fats fraudulently added to butter. The determination is carried out by gas chromatographic analysis of butter triglycerides on a capillary column having 65% phenylmethylsilicone as stationary phase. Over the past 25 years, various methods for the evaluation of butter purity have been proposed. The detection of adulterating vegetable oils is based on sterol analysis and the presence of these vegetable sterols in butter represents clear evidence of fraud. The official EU method for the detection of animal fats such as lard and tallow is time consuming and tedious; there are also problems of reproducibility and accuracy at low concentrations of the additives. The method proposed in this article allows us to detect the presence of extraneous vegetable and animal fats in a simple, rapid and precise way even when the quantity added to butter is minimal. The analysis is based on the best currently achievable resolution of single triglycerides components and a comparison with the profile observed for reference samples of certifiably pure butters. Moreover, by comparing each single sample analyzed with the EEC “BCR 164 RM” butter standard taken as reference, the present procedure can be used not only to evaluate purity but also to introduce a new parameter, “quality.” The latter is defined as the similarity between the sample percentages of single triglycerides with those in butter standards. The proposed method is simple and easy to execute, even by a nonspecialist technical staff.