Aroma Compounds | Esters, Aldehydes, and Thiols

Terpenes are amazing, but what about esters, aldehydes, and thiols? Today we’re taking a closer look at these aroma compounds.

The cannabis industry has opened up a vast world of study into various botanical compounds. For obvious reasons, many are primarily concerned with cannabinoids like THC and CBD. However, overlooking the variety of aromatic compounds means you’re missing the big picture. Plus, we’re not just talking about terpenes.

Think about your favorite botanical scent. Whether it’s vanilla, hops, orange blossom, or cedar, it’s made up of hundreds of different aromatic compounds. Yes, terpenes play a large role in the overall aroma, but there are other botanical compounds that contribute to the overall scent and sometimes even the effects.

Read on and discover just how massive the world of aroma compounds truly is.

Reading Time - 4.5 min

What Are Esters?

If fruits like pineapples, strawberries, and bananas actually came with ingredient labels, you’d find this particular aroma compound on them. In fact, if you take a look at the labels on a variety of perfumes, soaps, and detergents, you’ll probably see ingredients with the suffix “ate.” Those are esters!

These organic compounds can be found in a variety of places because of their pleasant smell. They’re formed by a condensation reaction occurring between alcohol and carboxylic acid (this reaction is known as esterification). When this happens, water molecules end up getting eliminated because they’re the smaller molecule.

Different esters are produced depending on which type of alcohol and carboxylic acid are combined. For example, the fatty acid ester Isopropyl Palmitate is formed when Isopropyl Alcohol and Palmitic Acid are combined.

On top of that, certain esters have potent antioxidant properties. According to a study by Food Chemistry, resveratrol esters and resveratrol ester derivatives have the potential to be functional food ingredients with beneficial properties because of their antioxidant characteristics.

In the food industry, esters are often used to enhance flavor and as emulsifiers. They’re also becoming increasingly popular in the personal care industry because of their emollient, solvent, thickening, surfactant, and fragrance properties.

What Are Aldehydes?

Like esters, aldehydes are organic compounds that may also be synthetically created. Aldehydes are reactive compounds that naturally occur in things like cinnamon bark, vanilla bean, rose, and more. Common aldehydes like formaldehyde and acetaldehyde are used to create other chemicals for resins, dyes, perfumes, etc.

Certain aldehydes actually play an important role in plant health. According to Phytochemistry, “C6-aldehydes, such as (Z)-3-hexenal, (E)-2-hexenal, and n-hexanal, are volatile compounds formed by hydroperoxide lyase (HPL) and found in most terrestrial plants. They are fungicidal and bactericidal compounds, and are also signaling compounds to induce defense responses in plants.”

Aldehydes are a common ingredient in the perfume industry, but only those with higher molecular weights. Aldehydes with low molecular weights tend to give off an odor of rotting fruit, whereas those with higher molecular weights are usually very pleasant.

Other industrial applications include resins, dyes, organic acids, and perfumes for products like cologne, detergents, and soaps. Formaldehyde is one of the most widely produced industrial aldehydes because of its preservative and anti-bacterial properties.

What Are Thiols?

If you’re a wine connoisseur, then you might have mixed feelings about thiols. That’s because having a large quantity of thiols in wine is considered a fault…unless you’re a fan of garlic. These organosulfur compounds smell fruity in tiny amounts, which is the case for Sauvignon Blanc and Riesling. In larger quantities, however, thiols can give off an unpleasant garlic aroma.

Thiols even have an important place in the beer industry! While they were only identified in the hops plant in the early 2000s, three thiols in particular contribute to popular beer flavors.

• 4-mercapto-4-methylpentant-2-one (4MMP) has the flavor and scent of box tree, black currant, and ribes.
• 3-mercaptohexan-1-ol (3MH) emits an exotic aroma of rhubarb and citrus.
• 3-mercaptohexyl acetate (3MHA) smells like passion fruit and guava.

These organic compounds are very similar to alcohols and phenols, except that they contain a sulfur atom in place of an oxygen atom. Plants produce thiols because they play an important role when it comes to stress responses. For example, the thiol Tripeptide Glutathione has antioxidative properties that influence stress responses to things like drought, temperatures, UV damage, and more.

One review even said, “Damage to plant tissues is often marked by a breakdown of the [tripeptide glutathione] system. Besides its role as protectant, [tripeptide glutathione] is thought to play a role in cellular signaling and stress sensing.”

Today, thiols have a surprisingly wide array of applications. One review discusses the medicinal applications of thiols, “Thiol-containing drugs can reduce radicals and other toxic electrophiles, restore cellular thiol pools, and form stable complexes with heavy metals such as lead, arsenic, and copper. Thus, thiols can treat a variety of conditions by serving as radical scavengers, GSH prodrugs, or metal chelators.” 

Additionally, thiols are often used in the pharmaceutical, insecticide, plastics, and rubber industries.

There Are Hundreds of Aroma Compounds

With the most advanced 3D analysis from flower to essential oil, we're the leader in botanical extraction, terpene and aroma compound research. Our technology, research, and manufacturing makes it possible to reproduce each cultivars' unique profile using botanically derived formulations. 

Bottom line? We’re REALLY interested in terpene science and the practical applications of aroma compounds.

We would love nothing more than to discuss terpenes all day, so contact us today if you have any questions about adding terpenes to your products. 

READ NEXT → What Are Terpenes and Terpenoids?