Casein fraction of bulk milks from different caprine breeds

The relative amounts of the major caseins in the total casein fraction from bulk milks of four different caprine breeds (two indigenous Greek and the highly selected Alpine and Saanen) were determined by alkaline urea polyacrylamide gel electrophoresis and by reversed-phase HPLC. Both methods revealed differences with regard to the αs1-casein fraction of the different breeds. The estimated values, expressed as percentage of total caseins, ranged as follows: for αs1-casein from 9.9% to 25.6%, for αs2-casein from 12.5% to 18.9%, for β-casein from 51.1% to 58.4% and for κ-casein from 9.9% to 13.5%. The lowest αs1-casein and the highest β-casein and κ-casein percentages were found in the casein fraction of the Saanen breed.