2020 年 26 巻 1 号 p. 17-23
Steviol glycosides are found in the leaves of Stevia rebaudiana Bertoni plants and have been used as natural, high-intensity sweeteners. Rebaudioside D (RebD) is a steviol glycoside derivative that has a similar sweetening profile to that of sugar; however, it is poorly soluble in water. Therefore, in this study, polymorphs of RebD showing greater solubility were investigated. We identified at least two novel polymorphs using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). We identified the transition to one polymorphic form of RebD (named “form α”) by desolvation at about 50 °C, and the other (named “form β”) at about 70 °C. Both forms exhibited greater water solubility compared to untreated RebD. This is the first report of RebD polymorphs with improved solubility, which may contribute to the production of RebD with both a sugar-like taste profile and high-solubility property.
