Impact of sucrose crystal composition and chemistry on its thermal behavior

Abstract

Though crystalline sucrose is an abundant and highly refined organic compound, its thermal behavior is complex and not fully understood. The objective of this research was to investigate the influence of the composition and chemistry of the sucrose crystal on its thermal behavior, especially as related to the origin of the small endothermic DSC peak observed for most cane sucrose sources, but not for beet sucrose sources, using a variety of analytical methods and techniques. Based on the evidence herein, we assert that the presence of the small endothermic DSC peak is associated with the onset of thermal decomposition of sucrose within mother liquor occlusions, initiated by hydrolysis and mediated by the composition and chemistry of the sucrose crystal. Any factor that affects the composition and chemistry of the sucrose crystal will in turn influence its resultant thermal behavior. This assertion further explains the complex sucrose thermal behavior issues that have heretofore not been completely elucidated, including the wide variation in the literature reported melting temperature values (location of Tmonset), the variation in the number and magnitude (ΔH) of the endothermic DSC peaks obtained, and the heating rate dependency of the melting temperature.