As many of you know, my wife Jane is diabetic and she is therefore always looking for ways of preparing food with as little sugar as possible. Recently she tried a bread-making experiment to see whether it would be viable to replace the sugar she normally uses in bread with a product called Perfect Sweet (a trade name for the artificial sweetener Xylitol), which has recently come onto the market here in the UK.
Xylitol has properties that make it particularly useful for diabetics. Absorbed more slowly than sugar, it does not contribute to high blood sugar levels or the resulting hyperglycemia caused by insufficient insulin response. However...
Jane often makes bread in an electric bread-maker, which consistently turns out very nice bread. The recipe she uses for a plain white loaf uses four level tablespoons of sugar. This time she replaced the sugar with Xylitol. In every other respect she used exactly the same ingredients and method. The result was disappointing. The loaf came out what I call "claggy" - heavy and doughy, and it had not risen very much at all. The bottom part was very brown, but the upper crust was still white and flabby. We think maybe the Xylitol killed the yeast, or at least stopped it performing properly.
The loaf was not fit for human consumption, and went to feed the birds, and Jane immediately set-to to make another loaf using the conventional recipe, which turned out perfect as usual. In my picture above you can see the difference. (Xylitol loaf on the right, if you hadn't already guessed!).
So, the conclusion is: Xylitol is not suitable for bread-making! I'm sure it is useful for other things though. Jane is planning to try it in Cranberry sauce for with the Christmas dinner.