Precision of milk fat quantitation in mixed fats by analysis of butyric acid

Quantitation of the milk fat content in mixed fats is of interest in food a nalysis. It can be achieved by calculation from the butyric acid (C4) conte nt in the mixed fat and a mean C4 content for pure milk fats. Alternatively , instead of applying a C4 mean value, the C4 content in the actual milk fa t can be used if this reference sample is available. A recently improved an alytical method based on gas chromatography of butyric acid methyl ester us ing an internal standard has been applied to determine the milk fat content in mixtures with beef tallow, lard, soybean oil, olive oil, sunflower oil, palm kernel oil and palm oil ranging from 1 to 90 % milk fat content. With in the whole range of mixtures, mean absolute deviations between the determ ined and the actual milk fat content were below 0.5 % and the maximum absol ute deviation was not more than 1.0 % when using the reference sample. The overall mean absolute deviation was 0.04 % for milk fat contents of 1 to 10 % and 0.28 % for milk fat contents of 10 to 90 %.