Process/Product Control: Analysis of Cheese by Proteomics Techniques

Almost all the applications of proteomics analysis to milk and cheese originate from the heterogeneity of the major milk proteins among the mammalian species. Urea polyacrilamyde gel electrophoresis (Urea‐PAGE) technique separates proteins according to their mass‐to‐charge ratio, using the naturally occurring negative charges that each protein shows when solubilized in alkaline buffers. With sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) analysis, proteins react with SDS by hydrophobic interactions, producing a uniformly negatively charged complex, which is resolved according to its molecular weight. Isoelectric focusing electrophoresis (IEF) separates proteins according to their isoelectric point. After the electrophoresis, liquid chromatography has been extensively used to separate and quantify milk proteins. The liquid chromatography‐mass spectrometry (LC‐MS) systems are made of three main parts: the liquid chromatography system, the interface, and the mass spectrometer. Capillary electrophoresis (CE) is an analytical technique that separates ions based on their electrophoretic mobility in submillimeter capillaries with the use of an applied voltage.