I am getting ready to make some back to school cookies and found a recipe for cinnamon apple cookies, which I am going to test for spreading and the royal icing recipe that is with it says to add apple juice concentrate to the icing mix. I am not great at understanding the science behind certain things. Does anyone know if the apple juice concentrate will affect the hardening of the icing or make the icing look spotty. Thank you.
If there are no egg whites in the icing, then it won't dry as fast as "royal icing", which, by definition, contains egg whites.
It's the protein in the egg whites that makes royal icing dry so fast (and which makes it dry hard). So, depending on what else is in this icing recipe, the icing may or may not behave like royal icing.
@Julia M. Usher thank you, I decided not to risk adding the apple juice concentrate to the royal icing because I needed to get the cookies finished, I'll make them when I have no commitment and see what happens?
Sounds good. I'll be interested to hear the result.
I've never tried apple juice concentrate, but I imagine that a good alternative would be to mix (oil-free) lemon juice into your royal icing. The tartness of the lemon juice would complement the apple-cinnamon flavors and might evoke the tangy effect of an apple, even though it doesn't have the same taste.