Shortening is any fat that is solid at room temperature and used to make crumbly pastry. The reason it is called shortening is that it prevents cross-linkage between gluten molecules. Cross linking gives dough elasticity. In pastries such as cake, which should not be elastic, shortening is used.
Originally, Shortening was synonymous with Lard, and with the invention of margarine by French chemist Hippolyte MÃ¨ge-MouriÃ¨s in 1869, margarine also came to be included in the term. Since the invention of hydrogenated vegetable oil in the early 20th century, “shortening” has come almost exclusively to mean hydrogenated vegetable oil. Vegetable shortening shares many properties with lard: both are semi-solid fats with a higher smoke point than butter and margarine. They contain less water and are thus less prone to splattering, making them safer for frying. Lard and shortening have a higher fat content compared to about 80% for butter and margarine.
Although butter is solid at room temperature and is frequently used in making pastry, the term “shortening” seldom refers to butter but is more closely related to margarine.