Physical State Study of (Sugar Mixture)-Polymer Model Systems

Abstract

The physical state of components in the unfrozen solute phase of frozen solutions was determined by using differential scanning calorimetry (DSC) for mixtures of lactose, sucrose, and trehalose with albumin, gelatine, or cornstarch. An equal weight ratio (1:1) of lactose-sucrose, lactose-trehalose and sucrose-trehalose mixtures with polymer systems (sugar mixture-albumen (1:1:1), gelatine (1:1:1), and cornstarch (1:1:1), as well as cornstarch-gelatine (1:1:1:1) was used. Mixed sugar mixture (lactose/sucrose)-polymer systems were further studied for maximum freeze-concentration in complex systems. A comparative thermal study between sugar-polymer and mixed sugar-polymer systems was conducted. The sugar-polymer and mixed sugar-polymer systems showed similarities and differences in thermal behaviour. The similarities included maximum freeze-concentration of a frozen system at an annealing temperature (T_m´-1) °C, constant initial concentration independent onset of glass transition T_g´, and onset of ice melting temperature T_m´, and increased in temperature difference between T_g´ and T_m´ or increase in broadness of transition with the addition of polymeric compound.

Keywords:

• Freezing
• Frozen state transitions
• Freeze-concentration
• Glass transition
• Surcose
• Lactose
• Trehalose
• Ice melting
• Water

ACKNOWLEDGMENTS

This study was carried out with financial support from Higher Education Authority of Ireland PRTLI Cycle 3.