I have a cake recipe that calls for 1/2 cup of sorbitol. I would like to use stevia instead since I am concerned about the side effects of sorbitol. How do I make that substitution? I could just add water to the stevia equivalent for the sorbitol amount to bring the stevia to 1/2 cup of volume. But I don't know if that will have the same effect as using the sorbitol. I know that using unsweetened applesauce will help with moisture retention. Any suggestions?
According to stevia.net one tablespoon of stevia (in powder or liquid form) is the 'equivalent' of one cup of sugar.
Similarly, lowcarbdiets.about.com tells us that sorbitol is 60% of the 'sweetness' of sugar.
Using sugar as a common denominator, 1/2 cup of sorbitol = .83 cup of sugar and so you should use ~.83 Tablespoons of stevia to gain the relative sweetness.
That calculated, I would mix 1 tablespoon of stevia with 1 cup of unsweetened applesauce and then use 3/4 of a cup + 1 tablespoons of the mixture, and then adjust from there.
Conversions like this are admittedly 'imprecise' but this should give you a good approximation to start from...your mileage may vary.
Polydextrose is for the humectant with sucralose for the sweetness
ive not used polydextrose too much, but try a 60/40 polydextrose/sucralose mix to replace the sorbitol by volume (not weight)