Development and validation of RP-HPLC method for the quantitative estimation of αs1-genetic variants in goat milk

A high-performance liquid chromatographic (HPLC) method was developed and validated for separation and quantification of the most common genetic variants of αs1-casein in goat's milk, to evaluate the effect of αs1-casein polymorphisms on casein content. Chromatography was carried out by binary gradient technique on a reversed-phase C8 Zorbax column and the detection was made at a wavelength of 214nm. The procedure was developed using individual raw milk samples of Girgentana goats. For calibration experiments, pure genetic variants were extracted from individual milk samples of animals with known genotypes, considering that commercial standards for goat genetic variants were not available. The data obtained for Girgentana goat breed showed that A, B, F variants were alleles associated with a content of αs1-casein in milk of 3.2±0.4, 5.4±0.5 and 0.7±0.1g/L, respectively, whereas N variant was a 'null' allele associated with the absence of αs1-casein in milk.