State diagrams for mixtures of low molecular weight carbohydrates

• State diagrams for sixteen sugar mixtures were developed.
• The effect of sugar composition on Tg, Tg′, Tm and Tm′ values was investigated.
• Different procedures to estimate the xs′ values from state diagrams are illustrated.

The objective of this research was to develop state diagrams of model food systems prepared with several fructose/glucose/sucrose mass fractions as a basis for studying products obtained from natural juices. A total of 16 sugar mixtures, including pure components as well as binary and ternary mixtures, with freezable and reduced moisture, were prepared and subjected to thermal analysis using differential scanning calorimetry (DSC), where freezing points (Tm and Tm′) and glass transitions values (Tg, Tg′) were determined. The expected decrease of Tg due to the plasticizing effect of water and the depression of Tm as a function of increasing solids concentration were adequately predicted (R2 > 0.94) using the Gordon–Taylor and Chen models, respectively. Results showed that Tg and Tm depression were influenced significantly by sugar composition (p < 0.05). Tm′ and Tg′ values ranged from −42.8 to −32.4 °C and from −55.9 to −43.1 °C, respectively and were also sugar composition dependent (p < 0.05). Constructed state diagram showed that solid mass fraction at the maximal-freeze-concentration condition (xs′) varied from 0.772 to 0.842 (g solids/g sample), however, significant effect of the sugar composition was not observed for xs′ values.