Bacon Fat

We’ve all experienced the delicious, smoky aroma that comes with sizzling bacon. What most of us don’t realize is that this delight comes from a complex biological process known as lipolysis. Lipolysis is the chemical breakdown of triglycerides in fat cells, leading to production of small fatty acid molecules such as butyric acid, the compound responsible for bacon’s unmistakably savory taste and smell. In this post, we’ll explore the complexities of lipolysis—from its chemical bonds to its industrial applications—to learn more about this remarkable flavor enhancer.

A Primer on Triglycerides

Triglycerides are the main component of body fat and, as such, are among the most abundant compounds in the human body. Hormones known as “lipases”—enzyme-driven proteins that exist in both the liver and adipose (fat) tissue—initiate the breakdown of triglycerides into smaller molecules. This process is called lipolysis. A triglyceride can be thought of as a single large molecule, made up of three smaller molecules called fatty acids. Every fatty acid contains a carboxylic acid group (-COOH) at one end and a variety of hydrocarbons (CH2) ranging from 3 carbon to 32 carbon (C3 to C32) at the other end. The carboxylic acid groups of fatty acids from the same triglyceride molecule can react with one another, creating bonds that hold the molecule together.

The specific hydrocarbon components at the “tail” end of each fatty acid will determine the flavor characteristics of the triglyceride. In the case of bacon fat, the major contributors to its umami flavor are butyric acid (C4H8O2) and caproic acid (C6H12O2). Butyric acid, in particular, is often referred to as the “bacon molecule”. Its strong odor is the result of its carbon-hydrogen (C-H) bonds breaking down, releasing molecules that react with olfactory receptors in the nose.

The Breakdown Process

So how exactly does a triglyceride become bacon fat? It all starts with the body’s lipases. These lipases attack the triglyceride molecule at the ester linkages that join the three fatty acids together. Once the triglyceride is broken into its component parts, the lipases catalyze additional reactions that facilitate further breakdown of the fatty acids. As the reaction begins, the various hydrocarbon chains of the fatty acid tails break apart one by one. This is known as a cleavage reaction, where single bonds between carbon atoms are broken. If a carbon atom previously connected to two hydrogen atoms, the atom is left with three unpaired electrons and forms a carbocation.

At this point, the carbocation formed will immediately begin to react with other molecules in its vicinity. The process of breaking single bonds and forming new ones is known as a substitution reaction. Depending on the reactants and conditions, the carbocation may form a variety of new bonds, allowing it to become part of a new triglyceride molecule. Ultimately, the various hydrocarbon chains released during this reaction combine in a variety of ways to ultimately produce small fatty acid molecules such as butyric and caproic acid.

Pigging Out

Now that we understand the highly technical processes behind creation of bacon fat, let’s take a look at the journey that takes this flavor enhancer from hog to human. It all starts with the pig. As animals with advanced digestive systems, hogs consume a high carbohydrate diet consisting of vegetables, grains, and animal sources. Once consumed, their body breaks down the carbohydrates into glycerol, the backbone of fatty acids, which is essential for triglycerides to be created. Through a series of metabolic processes, the glycerol then bonds with three fatty acid chains to form the triglyceride molecule.

Once created, these triglycerides are stored in the animal’s fat cells and serve as a fuel source when energy reserves are low. When the animal needs additional energy, lipases break apart the triglycerides, releasing both glycerol and fatty acid components. Once broken, the fatty acids and glycerol are shuttled off to different areas of the body for use. These processes result in the release of bacon-flavored compounds, making their way through the animal’s digestive tract and exiting in the form of waste.

Industrial Applications

Now that we’ve followed the bacon fat from living organism to non-living product, let’s explore the various industrial applications of this savory compound.

Perhaps the most popular application of bacon fat is as a flavor additive for foods. When heated, bacon fat begins to release its savory odor and taste, making it a popular flavor enhancer for baked goods, sauces, and other savory dishes. Bacon fat is also increasingly popular among craft brewers, who use it to add flavor and complexity be to their drinks.

Beyond its culinary applications, bacon fat has entered the industrial market as well. While the use of food-based biodiesel has been gaining traction in recent years, scientists have recently uncovered the advantages of turning bacon fat into a viable standalone energy source. Researchers have developed a method for refining the triglycerides found in bacon fat into a pure form of biodiesel, known as triglycerides glycerides (GTGs). This process involves catalyzing triglycerides using liquid and supercritical CO2 to form glycerol and GTGs, both of which are forms of biodiesel fuel.

Conclusion

Bacon fat has come a long way since it first appeared on caveman’s griddles hundreds of thousands of years ago. From its basic chemical structure to its myriad of industrial applications, the many components of bacon fat continue to enthrall and enrapture us all. Once it is created in the animal body, bacon fat travels to a variety of places—from the kitchen table to engine tanks. Regardless of where it ends up, one thing is certain: bacon fat will remain in our hearts and stomachs for many years to come.