Characterization of ewe's milk by capillary zone electrophoresis

The purpose of the present work was to develop a procedure able to separate and identify the major protein components of ewe's milk by capillary zone electrophoresis (CZE). Thirty-five individual milk samples of Massese breed were analyzed using a coated capillary. The analyses were performed at pH 3.0 at a temperature of 40 degrees C in the presence of 6 M urea. The purification of casein fractions was carried out by preparative fast protein liquid chromatography and the CZE results were confirmed by polyacrylamide agarose gel electrophoresis (PAAGE). The identification of whey proteins was also carried out by comparison with high-performance liquid chromatography data. The present study permitted the identification of the major components of ewe's milk by high-resolution electropherograms and characteristic migration times (tM). it was also possible to detect the presence of genetic variants of beta-lactoglobulin. The tM of k-casein was determined after enzymatic action of chymosin by verifying the simultaneous formation of p-k-casein. In most of the samples a fast moving alpha-s2-casein variant was identified by comparison with PAAGE results. Minor genetic differences were found in other casein fractions for this pool of samples.