INFLUENCE OF PROTEIN ON PHASE-TRANSITION OF AMORPHOUS SUGAR

In order to investigate the influence of protein on the phase transiti ons of amorphous structure of sugar, we carried out differential scann ing calorimetry (DSC) analysis of freeze-dried sucrose containing vari ous contents of water and bovine serum albumin (BSA). Glass transition temperature Tg, crystallization temperature Tcr, and melting temperat ure Tm were measured. Tg, Tcr, and Tm decreased with increasing water activity. Addition of BSA raised Tg except the case that water activit y was low (up to about 0.1). Tcr increased linearly with BSA content, and Tm did not depend on BSA content. The increase in Tg and Tcr with BSA suggests that protein contributes to stabilizing amorphous structu re of sugar.