Thermal Study of Fructooligosaccharides and Water-soluble Dietary Fiber

Fructooligosaccharides (FOS) are complex sugars found in vegetables and fruits. FOS have high hygroscopicity that cause deliquescence with wetness in the atmosphere. However, the combination of FOS and Acacia Fiber, known as water-soluble dietary fiber, leads to a decreasing effect of hygroscopicity. In this study, we investigated physical properties directly related to that effect using thermal analysis. FOS, Acacia Fiber, their Combination Product and Blend, which included them in the ratio of 1 to 1, were used as samples. Two glass transition regions were observed from modulated DSC measurements, which provides infolination about the reversing characteristic of thermal events, in Combination Product and Blend, respectively. The lower glass transition temperatures in both samples were almost the same, and they were thought to be those of FOS. However, the higher glass transition temperatures in both samples were different. This result would make it possible to suppose that the amorphous structure in the Combination Product might be formed into a much more stable state than that in Blend, and furthermore that the glass transition of the combination of FOS and Acacia Fiber is relevant to its hygroscopicity.