Analysis of monosaccharides in bovine, caprine and ovine kappa-casein macropeptide by gas chromatography

Monosaccharides present in kappa -casein macropeptide (CMP) from bovine, ov ine and caprine milks have been determined by gas chromatography after acid hydrolysis with trifluoroacetic acid (TFA) or methanolysis with HCl-methan ol. The method has been evaluated for repeatability and recovery using myo- inositol as internal standard with satisfactory results. Galactose, N-acety l-galactosamine and neuraminic acid were found in the kappa -casein macrope ptides from the three species and similar levels of galactose and N-acetyl- galactosamine were found after treatment with TFA and HCl-methanol. Bovine CMP exhibited the highest level of glycosylation. In general, the main comp onent of the carbohydrate fraction was neuraminic acid. The method is suita ble for the analysis of monosaccharides in CMP.