EVALUATION OF 2 METHODS FOR THE DETERMINATION OF LACTULOSE IN MILK

Two conventional methods for the determination of lactulose in milk we re compared, namely the colorimetric-enzymatic method and the gas chro matographic method. Increasing lactulose concentrations were added to raw milk samples. For concentrations of lactulose higher than 50 mg L( -1) both methods had a similar accuracy and precision. However, the en zymatic method was more sensitive and had a detection limit of about 1 0 mg L(-1). The detection limit for the gas chromatographic method was between 50 and 100 mg L(-1). In contrast to the gas chromatographic m ethod, the enzymatic method can be used to discriminate between UHT-mi lk and high-pasteurized milk.