Cornstarch or Corn flour (for thickening): 1 tablespoon = 2 tablespoons all purpose flour or
1 tablespoon potato starch or rice starch or flour 1 tablespoon arrowroot 2 tablespoons quick-cooking (instant) tapioca For other uses such as the main flour it's rather tricky I think it's best to only substitute Corn flour if it's for thickening.
no
No
No.
corn meal
Not normally. Corn flour is very different from wheat flour. It would work as a thickener in the same way although the taste would be somewhat different, but in baking you could not substitute corn flour for wheat flour.
you put corn starch in the recipe instead of flour by using the corn starch bag
yes you can
Flour and corn starch are measured the same, but the results aren't always the same.
Yes but it won't be as good, most likely.
Yes you can but many people use cornstarch.
Yes but it won't be as good, most likely.
No, cornflour would not substitute for gram flour.