Study on the effectiveness of different parameters on the evaluation of butter content of mixtures

To evaluate the milk fat content of a blend, the EU legislation indicates that the butyric acid content, expressed as methyl butyrate, should be multiplied by a factor of 25. The need to refer to a fixed content of butyric acid of milk fat in order to define the composition of the mélange, is one of the problems involved in calculating the milk fat content of a mixed product. In order to verify the effectiveness of butyric acid, as well as other parameters, in the characterization of mélanges, the Subcommittee on Vegetable and Animal Fat decided to carry out a characterization study on several blends. Mixtures were prepared (2-20% of milk fat) with 2 different vegetable matrices, and butyric acid content (expressed as methyl butyrate), fatty acid, triglyceride and sterol composition were determined in all samples. The effectiveness of the different parameters was evaluated in predictive terms, considering that usually, the testing laboratory receives only the blend, for the analysis, but not the raw materials that were used for its production. The calculation of the percentage of milk fat by applying the EU Regulation indications, led to an assessment error higher than 12%, even in samples containing more than 10% of milk fat. Less satisfactory results were obtained using triglycerides and cholesterol, due to the high natural variability of these constituents in vegetable (triglycerides) and milk fat (cholesterol) matrices. A lowest quantification error (10%) was obtained for mixtures containing 5% of milk fat or more, when, together with butyric acid, other fatty acids (C10:1, C14:1, C15iso, C15anteiso, C17iso and C17anteiso) that are also characteristic of the milk matrix and are therefore absent in the fat of vegetable origin, were taken into account