HPLC/UV analysis of proteins in dairy products using a hydrophobic interaction chromatographic column

High-performance liquid chromatography using a Chrompack P-300-RP column co ntaining a polystyrene-divinylbenzene copolymer-based packing was examined to analyze bovine milk protein components. The separation of major raw-milk proteins could be performed rapidly and reliably with this HPLC/UV method. The determinations were performed in the linear ranges of 0.01-2.0 mg/ml f or alpha -lactalbumin, 0.04-2.5 mg/ml for caseins and 0.02-2.0 mg/ml for be ta -lactoglobulin. The validity of the method was verified. Since the chrom atographic column enabled the quantification of only "native" milk proteins , the extent of denaturation and loss of milk proteins could be examined. T hus, evaluation of heat-induced proteins denaturation was carried out in ra w milk heated for 5 min at pre-determined temperatures.