Wow...a Renta yam as thickener for a blended fruit drink? To me, that is oddly creative and something I will try. Though since I'm not on the island at the moment, the next best thing I can think of to substitute for it here in the US would be a boiled potato. I'm thinking that the drink will thick creamy and come out sort of "milkshake-ish". If so, substituting boiled potato (or the Renta when on the island) would be something people with dairy allergies could play around with - make their shakes without yogurt or ice cream yet still get somewhat the same thing. Will definitely have to experiment with this one!!