Identification and quantification of major bovine milk proteins by liquid chromatography
The risk of fraudulent manipulation of diary product content is high, for instance, replacing milk powder by whey is very interesting from an economic point of view. Therefore, there is a need to have suitable analytical methods available for the determination of all milk components, which is currently not the case, especially for the main proteins. The detection of potential manipulations requires then a clear analytical characterization of each type of bovine milk, what constitutes the goal of this work. The separation of the major milk protein components has been carried out by ion-pair reversed-phase HPLC with photodiode array detection, using a C(4) column. The overall optimization has been achieved using a statistical experimental design procedure. The identification of each protein was ascertained using retention times, peak area ratios and second derivative UV spectra. Quantification was based on calibration curves drawn using purified proteins. Major sources of uncertainty were identified and the full uncertainty budget was established. The procedure was initially developed using the skimmed milk powder certified reference material CRM 063R and then applied to various types of commercial milks as well as to raw milk. The method is able to separate and quantify the seven major proteins in one run and also to provide precise determinations of the total protein concentration. These are important results towards the further development of a reference method for major proteins in milk. In addition, the use of a certified material reference is suggested in order to make comparisons of method performance possible.
Bibliographic Reference: An article published in: Journal of Chromatography A, Vol.928 (2001), pp.63-76
Record Number: 200114063 / Last updated on: 2001-11-23
Original language: en
Available languages: en