'Hot and Cold' Sweets

kevinngsi_jie_81749

At a recent exhibition about experimental approaches to food, one company mentioned they made a line of 'hot and cold boiled sweets' - basically sweets with chemicals that dissolve both endothermically and exothermically in the mouth. COOL!! Unfortunately, they sold out before I could get my hands on them and it was too crowded to ask any questions. I've been thinking about this furiously and am embarrassed to say that despite my science background I can't really think of any candidates for exothermically dissolving compounds beyond, say, capsaicin (I mean, I'm assuming the product is a bit more sophisticated than mixing mint oil with chili oil), so I'm putting it out here! That aside, is there a strategy for simply having that endothermic/exothermic effect without the taste of something, like mint, for example? 

Chris_Young_80640

To get the cooling effect, you need the xylitol to be in a crystalline form. If you melt it and cast it as a sugar "glass" that doesn't recrystallize, you won't get the effect from the latent heat of fusion as the sugar alcohol goes from crystalline solid to liquid solution.

I believe that you could prepare a saturated syrup by boiling it to a high temperature, then adding some crystalline xylitol to the mixture as it cools to cause it to recrystallize as it hardens after casting.