I will also add our reason for not using cornstarch was the high likelihood that it was not only non-organic but probably geneticaly modified corn. Corn is one of those big no-no's to us.
Arrowroot or kudzu will replace the same way
Arrowroot is an excellent thickener and prefered by professional chefs. It thickens just like corn startch, but it retains it's thickening properties. Whereas cornstarch does not. If you overheat cornstarch it will reverse and start to thin your liquid again. Be sure to buy arrowroot, meaning read labels. Alot of commercial arrowroot is actually cornstarch.