Dielectric spectroscopic analysis of wet and well dried starches in comparison with other polysaccharides

The polymer dynamics of wet and well dried starches are investigated using the dielectric spectroscopy. In all starches three relaxation connected with the polymer dynamics have been observed. The beta -relaxation is associated with the local chain motion, the delta -relaxation with an unknown molecular origin and the beta (wet)-relaxation with motions of a water polymer mixing phase. The mixing of wet starches with vacuum grease not effect the polymeric dynamics observed. The biological origin and the type of the starches products have also no great influence on the polymeric dynamics and starches show a similar dynamic behaviour like other pure polysaccharides. The main point for the characterization of the segmental motion is the type of the glucosidic linkage and not its position and orientation at the repeating unit. In various acetyl-starches the beta -process can also be observed with low variations of the dynamic parameters. (C) 2001 Elsevier Science Ltd. All rights reserved.