Corn Starch

Cornstarch is made from corn and is a fine white powdery starch used to thicken pie fillings, sauces, gravies, and puddings. It does not thicken well with acidic liquids (most fruit are acidic).
Cornstarch can prevent eggs from curdling--very helpful in custards and helps heat transfer through custard more evenly which is helpful in custard pies.

Cornstarch has twice the thickening power of flour but it does impart a slightly starchy taste.

Cornstarch must be dissolved in cold water when added to any liquids. Liquids must be brought to full boil or sauce will have starchy taste and white color. Don't boil more than 3 minutes.

Does not contain gluten. Corn starch belongs to a group of food additives known as starches, thickeners and gels. It is also known as cornflour or Maize starch depending on where you are in the world.

Cornstarch is also frequently used as a replacement for talc in baby powder and is even being tested in making DVD disks that are biodegradable.