Water-polysaccharides interactions during apples drying process

In this work the state of water in samples of a food (apple) during the dry ing process was analyzed. Low resolution NMR, differential scanning calorimetry (DSC) acid sorption m easurements were performed on differently dried samples. It was possible to correlate the NMR proton relaxation time to the water activity aw=P/P-0, i n order to have an independent method for measuring this parameter. The cal orimetric curves showed the thermal transitions of different water populati ons and the sorption measurements on dry apple gave the fraction of water t ightly bond to the structure, which resulted about 30%.