Pastry margarine combines liquid and solid fats, and when it bakes inside the pastry, the margarine holds in steam and causes the pastry layers to rise and separate. Also known as emulsified fat, pastry margarine is used in puff pastries, Danish pastries and croissants.
Pastry margarine has a high plasticity, which means that small pieces bend without breaking. The non-greasy margarine is usually kneaded before it is added to pastry dough, and then the dough and the margarine are pressed together and folded over several times to create multiple layers. A finished pastry includes up to 35 percent pastry margarine.