Mix starch with cold water. Mix starch with oil or melted fat. Mix starch with larger amount of anohter dry ingredient. Picture of gelatin 1. Picture of gelatin 2.
All starches gelatinize.
But starches differ in their ability to thicken. Cornstarch thickens 2X more than flour. Cornstarch forms a hard, brittle gel. Potato or waxy starches don't gel. Picture of non gel.