Lemon Chemistry: Flavor and Aroma Profiles

lemon chemistryTo detect aroma, airborne chemicals must enter our nasal passages, the volatile compounds we call volatile or aromatic oils. Although flavor is somewhat influence by the sense of smell, it primarily requires solubility solubility to reach receptors in the mouth. Let’s explore a little lemon chemistry.

Lemon Chemistry: Flavor

The tongue detects four, perhaps five, flavors. They are sweet, salty, sour, and bitter. Some add savory¹. There can be no doubt the primary taste of lemon is sour. Mention sour and the organic chemist thinks of organic acids. Lemons are rich in three organic acids: citric, malic, and ascorbic (AKA Vitamin C). Citric acid predominates. Suck on a piece of citric acid and you’ll immediately think of lemons.

lemon chemistry

Lemon Chemistry: Aroma

The lemon’s odor is a more complex matter. Much of its smell is located in the peel or zest. For this reason, zest is commonly used in gourmet cooking. But lemon peels are also of historical importance to furniture aficionados.

Many are familiar with lemon oil in furniture treatment compositions. Aromatic oil from the lemon includes and terpenes such as L-limonene². D-limonene, the stereoisomer of L-limonene distinguishes the aroma of oranges. Additional fragrant compounds include certain coumarins.

Unfortunately, today much “lemon oil” is not really lemon oil. It often is, as the Smithsonian Institution suggests, “mineral oil with colorants and perfumes added.”

lemon chemistry

Did You Know?

What exactly are terpenes? They are a class of organic compounds or structures that can be built from the building block, isoprene². The reader may note the similarity between the words isoprene and neoprene. Chlorinated isoprene or chloroprene was used to produce artificial rubber or neoprene during WW2. In fact, some researchers, even today, seek a commercially feasible process for reclaiming limonene by vacuum pyrolysis of used tires.

Concluding Remarks

As is suggested above, the lemon aroma ingredient limonene is of great importance. It not only imparts the fragrance of the lemon in cooking and deodorants, it is useful in the treatment of furniture. It is also highly valued “natural” cleansing agent to replace more toxic cleansers in general purpose use. Practical results from showing an interest in lemon chemistry suggests we avidly pursue the chemistry of every living thing in the ecosystem.

lemon chemistry ¹ Or, umami. ² For further information concerning terpenes and the isoprene rule, see Terpenes and Terpenoids: Isoprene Rule


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  • Anthony Davis Reply

    I have a lemon tree that bears no fruit but the leaves seem to be full of the stuff that makes a lemon taste and smell – well – like a lemon.

  • Extraction Canopy Reply

    Lemon is great in cooking. I love ginger and lemon tea, especially in the winter or when I have a cold or sore throat. I squeeze the lemon and keep the juice to one side, then pour boiling water over the lemon peel and some slices of fresh ginger and leave to steep for a while. Then I add in the lemon juice and drink. One lemon and a few slices of ginger makes enough for 1 litre of the good stuff. Occasionally I add honey but it’s not necessary.

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