How does shortening make baked goods more tender?

Shortening makes baked goods more tender by weakening and lubricating the structure of the dough or batter. By coating the flour particles, fats interfere with the development of gluten, which prevents the final product from becoming too tough or elastic.12

The ability of a fat to produce this tenderizing effect is often referred to as its "shortening power". When fats are well-amalgamated into the mixture, they create a fine-textured, crumbly result, whereas keeping the fat in distinct bits—as is done with pastry—results in a flaky texture. Commercial shortenings may also include emulsifiers to further improve this tenderizing effect.123

While increasing the proportion of shortening generally enhances tenderness, it is important to balance the amount used; excessive fat can cause certain products, such as cakes, to lose their structure and fall.1