Do you think tapioca starch or arrowroot would work in place of the cornstarch for those of us who can't have corn? (kneadtocook.com)
If you prefer to use tapioca starch in place of the cornstarch, simply use twice as much tapioca starch. (dailyforage-glutenfree.com)
Amaranth that has been cooked and then chilled can also be used in place of cornstarch as a thickening agent for soups, jellies or sauces. (healthline.com)