Use of FTIR and mass spectrometry for characterization of glycated caseins.

This study investigates the potential of Fourier transform infrared spectroscopy (FTIR) to monitor glycation-induced changes in protein structure. Aqueous solutions of sodium caseinate and glucose (1:2 w/w, pH 6.7) were heated at 90 degrees C for 0, 10, 20, 40 and 60 min. Evidence for caseinate glycation was obtained by mass spectrometry techniques (electrospray (ESI) and matrix-assisted laser desorption ionisation (MALDI)). FTIR was able to discriminate between glycated and non-glycated sodium caseinate, when the data were analysed by multivariate statistical methods; principal component analysis (PCA) and soft independent modelling of class analogy (SIMCA). The techniques used were complementary and provided different levels of information about the glycated samples.