Published online by Cambridge University Press: 01 June 2009
Samples of caseins having different Ca contents as used in cheese processing were analysed by techniques using differential scanning calorimetry and thermally stimulated currents (TSC) before and after treatment with Na poly-phosphate, a food additive used in the manufacture of processed cheese. These techniques revealed structural changes induced by the salt, and the different types of water molecules associated with the protein are evident. This characterization is in agreement with results obtained by other techniques, particularly X-ray diffraction of proteins. Transmission electron microscopy of the same samples confirmed that the changes observed by TSC were associated with an unravelling of the protein.