The effect of cheese ripening on milkfat composition and the detection of fat from non-dairy origin

Cheese ripening is often associated with lipolysis of milkfat, an essential element of the development of cheese aroma. Because of the asymmetric molecular structure of milkfat, the partial breakdown of triacylglycerols (TAGs) to free fatty acids (FFAs) leads to noticeable changes in the composition of TAGs and fatty acids (FAs) that were bound to TAGs. Methods for authenticating milkfat purity are primarily based on the genuineness of FA or TAG composition. To investigate the impact of cheese ripening on foreign fat detection, 29 samples of differently ripened cheeses available on the German market were examined. The highest lipolysis occurred in mould-ripened and long-ripened cheeses, which often impaired authentication using butyric acid (C4). Authentication using TAG equations was less susceptible to increased fat acidity, but still had the potential to yield false positives. Strong correlations were found between the contents of FFAs, C4 and the analysed TAG C24 comprising certain diacylglycerols.