Determination of caprine serum albumin in milk using bromocresol green dye

The objective of this study was to develop and validate a colorimetric assay to measure caprine serum albumin (CSA) concentrations in milk. The principle of the say was based on the binding of albumin to bromocresol green (BCG) dye at pH 4.0. The absorption of the dye-albumin complex was determined spectrophotometrically at 640 nm. A linear relationship existed between CSA concentrations (0.01 to 8.0 mg/ml) and absorbance values. Intra-assay and interassay coefficients of variation for the proposed assay were 2.6% and 12% respectively. Recovery from milk samples spiked with albumins was 89.15% ± 7.6%. The developed assay was validated using 126 milk samples collected from lactating Saanen goats at various stages of lactation`. Caprine serum albumin concentrations in milk ranged between 0.31 and 0.52 mg/ml. The concentrations of CSA were significantly higher (p