Some recipes I have seen say to use egg white and water instead of lemon juice and water in peppermint creams.
Why is this? What does egg white do that water doesn't?
Well, the sugar and lemon can act as stabilizers to the egg whites. It would help stiffen up the cream and allow it to be more spreadable. So to answer your question, the egg white is actually what's making the creamy texture, with the help of some other things. You could also substitute cream of tartar which is the acidic bi-product from wine making instead of the lemon.