A DSC study has been carried out on isomalt, a commercial sugar alcohol derived from sucrose and widely used as a sweetener
in the food industry. Isomalt is a mixture of two isomers:α-D-glucopyranosyl–1-6-mannitol (GPM) and α-D-glucopyranosyl–1-6-sorbitol (GPS). Release of the water of crystallisation (around 100C)and melting (around 150C) have
been phenomenologically characterised using different scanning rates and heat treatments. The effect of dehydration/re-hydration
on the melting has been investigated. The isomalt glass transition, at about 60C, was studied on samples cooled after melting.
The dynamic aspect of structural relaxation of isomalt has been quantified by its fragility parameter. Glassy state stability
has been evaluated by performing ageing experiments at sub-Tg temperatures. During ageing, apart from the expected enthalpy relaxation effects, isomalt showed a peculiar behaviour, due
to its isomeric composition. These preliminary and phenomenological results have been interpreted in terms of isomer structure
and of carbohydrate-water interactions in the mixture.