Right about here it makes sense to have a short discussion about how various fats are used, especially in baking. Bakers and pastry makers (from big time commercial operations right down to home bakers) vastly prefer solid fats to liquid fats. Solid fats are in fact the very foundation of pastry. Their ability to stay more or less solid and plastic at room temperature (yet melt away with heat) is what gives croissant and puff pastry its layers, and pie and tart dough its flakiness. They are also an important flavor and texture component in all kinds of cakes.
Other uses for fat include of course deep frying, where again, solid fat reigns (melted, obviously). Saturation is a big advantage in frying, since the weak double bonds on unsaturated fatty acid chains allow other unwanted types of molecules to attach themselves, causing the fat to degrade. Solid fats are also desirable since they firm up again when they return to room temperature, which makes fried goods like doughnuts less greasy feeling and tasting.
In an ideal world, so-called “natural” fats would be employed for all these uses. At home, butter is not only the most practical, it’s also the most delectable choice for pastries, cakes, tarts and pies. Yet since it contains a mixture of solid and liquid fat, not to mention milk proteins and a fair amount of water (about 12%), it’s not a very good choice for frying. True, you can refine butter by melting it and skimming off the impurities (what’s known as “ghee”), but in general it’s far easier to use some other kind of fat to fry in. Before shortening was invented, most people used lard (really, an excellent choice for frying). Yet nowadays liquid oils are popular. Yes, they stay liquid after the frying process is over, and that makes the food a little oily, but a little extra oiliness is a small price to pay for a home-made doughnut.
For commercial baking operations it’s an entirely different playing field. Whether a local bakery or a national retail or wholesale baking operation, fat choices are more limited. Partly because natural solid fats (i.e. butter) are expensive. Yet price isn’t the sole factor that prevents Hostess from using real butter in its Ho-Ho’s. Butter, being partly unsaturated, goes rancid in a very short time (those darn double bonds again). Commcercial bakers could use a natural vegetable oil instead, yet since the oil would always be liquid, it would soak into packaging as well as make the product (be it a Ritz cracker, a powdered doughnut, Little Debbie Snack Cake, what-have-you) both look and taste limp and greasy. Plus, you again have the rancidity issue.
Thus, for a variety of reasons, solid fat is king in the world of bakery. But since butter is expensive and can’t be used for everything, and most people get upset when they see “lard” on their ingredient labels (and actually it can add a vague animal flavor to your chocolate cake) other solutions needed to be found.