Water-polysaccharides interactions during apples drying process

In this work the state of water in samples of a food (apple) during the drying process was analyzed.

Low resolution NMR, differential scanning calorimetry (DSC) and sorption measurements were performed on differently dried samples.

It was possible to correlate the NMR proton relaxation time to the water activity aw=P/P₀, in order to have an independent method for measuring this parameter. The calorimetric curves showed the thermal transitions of different water populations and the sorption measurements on dry apple gave the fraction of water tightly bond to the structure, which resulted about 30%.