Confused By Icing Sugar in Gluten-Free Foods, Products, Shopping & Medications Posted January 19, 2015 · Report to Admin I have a packet of Icing mixture here and the ingredients state sugar (sucrose) and tapioca starch. If I read those ingredients only I would assume it is gluten free. However underneath it says it contains gluten. How does it contain gluten?? Or is it like on lollies where the only ingredient is glucose syrup from wheat and it still says contains gluten, even though it doesn't.