Why should emulsifier shortening not be used for pie dough?

Emulsifiers are ingredients that help to combine liquids and fats such as shortening into a uniform mixture. This helps to keep pie dough from becoming tough or crumbly. Shortening is a solid fat that is used in baking to add richness and flakiness to baked goods. Emulsifier shortening contains additives that help it to disperse evenly throughout the dough and create a more tender crust.