De- and rehydration behavior of alpha,alpha-trehalose dihydrate under humidity-controlled atmospheres.
Effects of humidity were investigated on de- and rehydration behavior of alpha,alpha-trehalose dihydrate (T(h)) throughout simultaneous measurements of differential scanning calorimetry and X-ray diffractometry (DSC-XRD) and simultaneous thermogravimetry and differential thermal analysis (TG-DTA). When T(h) was heated from room temperature under dry nitrogen atmosphere, a metastable anhydrous crystal (T(alpha)) was formed at 105 degrees C after dehydration of T(h). The resulting T(alpha) melted at 125 degrees C and became amorphous, followed by cold crystallization from 150 degrees C giving rise to a stable anhydrous crystal T(beta). Under a highly humid atmosphere, on the other hand, T(beta) was formed at 90 degrees C directly as a result of T(h) dehydration. T(alpha) was readily rehydrated and turned back to T(h) when nitrogen gas with low water vapor pressure of 2.1kPa was admitted, whereas high water vapor pressure up to 7.4kPa was required for rehydration of T(beta) into T(h). This study provided a picture of pathways that link various solid forms of trehalose, taking into account the effects of a humid environment.
Furuki
Takao
T
Chemical Technology Division, Kanagawa Industrial Technology Research Institute, 705-1 Shimoimaizumi, Ebina, Kanagawa 243-0435, Japan.
Kishi
Akira
A
Sakurai
Minoru
M
D001272:Atmosphere; D002152:Calorimetry, Differential Scanning; D006813:Humidity; D013818:Thermogravimetry; D014199:Trehalose / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
D014867:Water; D014199:Trehalose