Electrifying Orange Peel Oils Produces Pleasing Smells

By Mark Miller

Research by Holger Zorn, PhD, and a team at Justus Liebig University Giessen and BASF may lead to a better way to produce flavor and fragrance compounds from the oils found in orange peels. The team combined ethanol and electricity to derive pleasant-smelling compounds, some of which may not have been previously identified.

Essential Oil

Peeling an orange is like digging into its essence. You plunge your thumb beneath the skin. As you pull it back, a mist that smells of pure orange is released. Part of the oil in this mist is a compound called limonene that occurs naturally in lemons, oranges, and other fruits. When collected from discarded peels, it’s used as a flavor and fragrance additive in beverages, perfumes, cosmetics, and other products.

Sustainable Oxidation

Limonene is often used in its original form, but it also serves as a starting point for creating other scents through a process called oxidation. Oxidation happens when a molecule, atom, or ion loses one or more of its electrons in a chemical reaction. Sometimes this involves an element or compound combining with oxygen, but not always. Common examples are the formation of rust (iron oxide) or the flesh of an apple turning brown when exposed to air.

Traditionally, a type of synthetic oxidation transforms limonene into compounds. This technique relies on environmentally harmful substances such as strong chemicals and heavy metals. Zorn and team found another way. They mixed limonene with ethanol and then applied an electric current. This electrifying process resulted in an amber liquid that produced 17 different fruity-, herbal-, and citrusy-smelling compounds.

This relatively simple process marks a different, more sustainable direction for deriving compounds. The next step is conducting safety evaluations before the compounds can be introduced in commercial products.

Not Just Another Nice Smell

While the research done by Zorn and team derived compounds that make products smell and taste better, the orange peels we often throw away provide a variety of other benefits. According to The Times of India, they contain high levels of polyphenols that can fight diabetes and obesity. They can cut through grease and condition wood in homemade, natural cleaners. You can use them to make pots for growing seeds, start a fire, or ward off mosquitoes. In research and the real world, there’s more to orange peels than meets the nose.