Effect of Calcium Maltobionate on the Glass Transition Temperature of Model and Hand-made Hard Candies

Glass transition temperature (T _g) is an important parameter for the physical quality control of hard candies. In order to understand the applicability of calcium maltobionate to hard candy, effect of calcium maltobionate addition on the T _g of model and hand-made hard candies was investigated. Freeze-dried calcium maltobionate-sugar (sucrose containing a small amount of glucose-fructose mixture) and calcium maltobionate-reduced isomaltulose mixtures were prepared as model candies, and their anhydrous T _g was evaluated using a differential scanning calorimetry. The anhydrous T _g increased linearly with the molar fraction of calcium maltobionate. From these results, it was expected that calcium maltobionate can improve the physical stability of normal and sugarless candies. For comparison, various commercial candies were employed, and their T _g was evaluated using a thermal rheological analysis. The T _g values were in the range of 28-49 °C. The T _g values were higher than 25 °C, which is significant with respect to the physical stability of the candies. Calcium maltobionate-sugar and calcium maltobionate-reduced isomaltulose candies were prepared as hand-made candies. The calcium maltobionate-reduced isomaltulose candies had higher T _g than the calcium maltobionate-sugar candies at each calcium maltobionate content, although reduced isomaltulose has a lower T _g than sugar. At a high calcium maltobionate content, calcium maltobionate-reduced isomaltulose candy had an equivalent T _g to the commercial sugarless candies, and thus practically acceptable stability was expected. In the case of calcium maltobionate-sugar candies, there was a possibility that the hydrolysis of sugar reduced their T _g. Vacuum-concentration will be useful to improve the T _g of the candies.