Effect of saccharides on glass transition temperatures of frozen and freeze dried bovine plasma protein

In this study, to preserve the integrity of plasma protein, protective agents, such as saccharides are added to produce a glassy (vitrified) state. Differential scanning calorimetry (DSC) was used to measure the glass transition (Tg), crystallization temperatures (Tc) of the solid freeze–dried bovine plasma protein and the glass transition temperature (Tg′) of the protein freeze solution, with the addition of inulin as protective agent, comparing the behavior with glucose and sucrose. The results indicated that transition temperatures increased with the molecular weight of the saccharide, conferring inulin a stabilizing effect at higher storage temperature. The Tg′ and the water plasticizing effect were estimated by means of two theoretical models: Miller/Fox and Gordon/Taylor extended for multi-component systems. The determination of the glass transition temperatures is useful in defining a freeze–drying cycle and storage stability of plasma protein concentrates.