Analysis of cows', ewes' and goats' milk mixtures by capillary electrophoresis:: quantification by multivariate regression analysis

Capillary electrophoresis was used to separate and analyze the casein fraction in mixtures of cows', goats' and ewes' milk. The differences between the capillary electrophoresis patterns of the casein fraction from the whole milk of each species allowed identification and quantitative determination of milk in binary and ternary mixtures. Principal components regression and partial least-squares regression were used to predict the percentages of milk of each species included in a mixture. The predictor variables were the peak areas of bovine and ovine alpha(s1)-casein; bovine, ovine and caprine K-casein; bovine beta-casein A(1) and A(2); and ovine and caprine beta(2)-casein and beta(1)-casein. The root mean square errors in prediction were lower than 2.4% in all cases. (C) 1999 Elsevier Science Ltd. All rights reserved.