Volumetric behaviour of maltose–water, maltose–glycerol and starch–sorbitol–water systems mixtures in relation to structural relaxation

The densities of amorphous maltose–water, maltose–glycerol and starch–sorbitol–water mixtures were measured using a vibrating-tube density meter and pycnometry. The volumetric change on mixing was investigated through the calculation of the quantity Δ V/ V, the difference between (experimental) volume of the mixture and the linear composition weighted pure constituent volumes (ideal mixing). For all of the systems studied the quantity Δ V/ V was negative and approached a minimum of −0.03 and −0.015 at mass fractions of maltose in the region of 0.75 and 0.85 for the maltose–water and maltose–glycerol mixtures, respectively. Results are discussed in the context of volume change due to structural relaxation of vitreous materials and related to the phenomenon of antiplasticisation. Excess volume of maltose- and starch-based systems are related to volume change due to structural relaxation of vitreous materials.