Differential Scanning Calorimetry Study of Phase Transitions Affecting the Quality of Dehydrated Materials

Abstract

Abstract Differential scanning calorimetry was used to determine the phase transitions of dried and rehumidified amorphous lactose, sucrose, and a mixture of sucrose and Amioca. Glass‐transition, crystallization, and melting temperatures decreased with increasing moisture content. The time to crystallization of amorphous lactose held isothermally above the glass‐transition temperature decreased as the temperature was increased. Isothermal crystallization time of lactose was a function of the temperature difference between the holding temperature and the glass‐transition temperature independently of moisture content. Amorphous biological materials are metastable showing temperature, moisture content, and time‐dependent phase transitions that affect their drying behavior, stickiness, storage stability, and quality.