I have an odd question, and I figure if anyone can help me with an obscure food issue, it's you guys. For a prop for a Halloween costume, I need to make drinkable fake blood. Most of the recipes I've run across have involved a corn syrup base. YUCK. I don't want the sugar high. I was thinking of using a cranberry or cran-grape juice as the base. It's about the right color. But I need to figure out how to thicken it and make it slightly opaque. Any suggestions?