Qualitative and quantitative analysis of bovine milk adulteration in caprine and ovine milks using native-PAGE

Native-PAGE (polyacrylamide gel electrophoresis) was used for the simultaneous qualitative and quantitative analysis of bovine milk adulteration in caprine and ovine milk using whole milk samples as well as their whey protein fraction Quantification was based on measuring band intensity of bovine beta-lactoglobulins in all milk mixtures and bovine alpha-lactalbumin in caprine/bovine milk blends Linear relationships were established between the band intensity of bovine beta-lactoglobulins and alpha-lactalbumin vs volume percentage of added bovine milk in all milk analysed with the correlation coefficient from 0 9950 to 0 9998 These correlations enabling the quantification of bovine milk percentage within the wide range from 3% or 5% to 90% in caprine/bovine and ovine/bovine milk blends respectively The differences between the actual percentages of bovine milk present in the adulterated milk samples and those calculated using the regression lines were less than or equal to 5% for all samples This method offers a rapid determination combined with unequivocal identification of the bovine whey proteins in almost every caprine/bovine or ovine/bovine milk mixtures (C) 2010 Elsevier Ltd All rights reserved