State transitions and freeze concentration in trehalose–protein–cornstarch mixtures

Abstract

State transitions of solutions of mixtures of trehalose, albumen, gelatin, and cornstarch were studied and state diagrams were established. Maximum freeze concentration was achieved by annealing of solutions at a temperature T m ′ −1 °C. The onset temperatures of glass transitions of maximally freeze-concentrated solutes, T g ′ , were lower and onset temperatures of ice melting, T m ′ , were higher for mixtures of trehalose, proteins and cornstarch when compared with those of pure trehalose. Solute concentration in the maximally freeze-concentrated phase, C g ′ , was 79% for trehalose, trehalose/albumin (1:1), and trehalose/cornstarch (1:1). The C g ′ of trehalose/gelatin (1:1), and trehalose/cornstarch/gelatin (1:1:1) was 74% and 75%, respectively. The state diagrams established with experimental and predicted T g values are useful for characterization of thermal phenomena and physical state of carbohydrate–protein–polysaccharide mixtures at various water contents.