The Chemical Nature of Oil of Bitter Almond: Benzaldehyde
The oil of bitter almond is known primarily by its chemical name, benzaldehyde. This aromatic aldehyde is the compound that gives this oil its characteristic almond-like scent and flavor. This distinction is critical for safety and application. While natural bitter almond oil contains a toxic compound, commercial products use the safe, purified or synthetic benzaldehyde.
Origins and the Toxic Component
Bitter almond oil comes from the kernels of the bitter almond tree, Prunus dulcis var. amara. This is a different variety than the sweet, edible almonds. The toxicity of this oil stems from amygdalin, a cyanogenic glycoside in the kernels. When the kernels are crushed and mixed with water, an enzyme called emulsin acts on amygdalin. This process releases benzaldehyde, glucose, and hydrogen cyanide (also known as prussic acid).
Unprocessed bitter almond oil is highly poisonous and can be lethal. This is why raw bitter almonds and their oil are not safe for consumption. Historically, there were medicinal uses for bitter almond oil, but these treatments are now considered dangerous.
Modern Production and Safe Applications
Modern commercial practices use the desirable flavor and aroma of bitter almond oil while eliminating health risks. This is achieved through these methods:
- Purified Bitter Almond Oil: The natural oil is distilled to remove the hydrogen cyanide. This creates a cyanide-free product that captures the marzipan aroma and is safe for use in flavoring and fragrancing.
- Synthetic Benzaldehyde: Benzaldehyde can be synthesized in a lab. This man-made version is a cost-effective and safe alternative, used in the food, cosmetic, and pharmaceutical industries. It's in imitation almond extracts for baked goods and candies.
Practical Uses of Processed Benzaldehyde
- Flavoring Agent: Gives foods their signature almond flavor, such as marzipan and amaretto.
- Fragrance: Used in perfumes, soaps, and scented products to impart a sweet, nutty aroma.
- Industrial Chemicals: Used to make other organic compounds and dyes.
- Bee Repellent: In beekeeping, benzaldehyde is used to drive bees away from honeycombs temporarily.
Comparison Table: Sweet Almond Oil vs. Bitter Almond Oil
| Feature | Sweet Almond Oil (Prunus dulcis) | Bitter Almond Oil (Prunus dulcis var. amara) |
|---|---|---|
| Source | Kernels of the sweet almond tree, the common edible variety. | Kernels of the bitter almond tree, a separate cultivar. |
| Composition | Contains beneficial fatty acids, vitamin E, and antioxidants. | Contains amygdalin, which releases toxic hydrogen cyanide upon breakdown. |
| Safety | Safe for consumption and topical application. | The raw oil is toxic and unsafe; purified versions are safe. |
| Scent | Mild, nutty aroma. | Strong, distinct, marzipan-like aroma. |
| Uses | Culinary oil, skincare, haircare, and massage oil. | Processed versions are used as a flavoring and fragrance agent; the raw oil is not used in consumer products. |
Conclusion: The Key Takeaways
Knowing that the oil of bitter almond is also known as benzaldehyde is important to understanding its nature. The name reflects its aromatic compound but hides the difference between its toxic state and its safe form. Always ensure any product is labeled cyanide-free or is a synthetic version. Sweet almond oil is the safest choice for cooking or cosmetics, while benzaldehyde is a safe flavoring and fragrance agent when processed.
For information on the toxicology of bitter almond and amygdalin, consult resources like the National Center for Biotechnology Information (NCBI) on PubMed Central.
Key Facts about Bitter Almond Oil (Benzaldehyde)
- Chemical Name: The key chemical is benzaldehyde.
- Toxic Source: Raw bitter almond oil contains amygdalin, which converts to hydrogen cyanide.
- Commercial Safety: Food-grade flavoring is either synthetic benzaldehyde or natural oil that is processed to remove cyanide.
- Flavor Profile: Benzaldehyde provides the marzipan-like flavor.
- Versatile Use: Processed benzaldehyde is used in flavoring extracts and perfumes.
- Dangerous Raw Form: Ingestion of unprocessed bitter almond oil is fatal and should be avoided.
FAQs
What is the primary chemical name for the oil of bitter almond?
Its primary chemical name is benzaldehyde. This aromatic compound gives the oil its distinctive cherry pit and marzipan-like scent and flavor.
Is bitter almond oil safe to eat?
Raw or unprocessed bitter almond oil is not safe to eat because it contains the toxic compound amygdalin, which can release poisonous hydrogen cyanide. Commercially sold bitter almond flavoring is either a synthetic version of benzaldehyde or has been processed to be cyanide-free and is safe for consumption.
What is the difference between sweet and bitter almond oil?
Sweet almond oil is a safe, nutrient-rich oil extracted from edible sweet almonds. Bitter almond oil, in its raw form, is toxic due to cyanide content and comes from a different cultivar. Only purified or synthetic bitter almond oil is safe for flavoring.
How is the toxicity removed from bitter almond oil used in food?
To make bitter almond oil safe for food, it undergoes a process, typically distillation, to remove the toxic hydrogen cyanide. What remains is the non-toxic benzaldehyde compound.
Why is benzaldehyde used as a bee repellent?
Benzaldehyde has been found to be effective as a bee repellent and is sometimes used by beekeepers. When placed near honeycombs, the odor encourages bees to move away, making it easier and safer to harvest honey.
Can I use bitter almond oil on my skin?
Topical application of bitter almond oil should be done with extreme caution and only with a heavily diluted, processed version that is certified cyanide-free. Raw bitter almond oil can cause skin irritation, and there is a risk of absorption of toxic compounds.
Are the terms 'Laetrile' or 'Vitamin B17' related to bitter almond oil?
Yes, laetrile and the historical, scientifically unfounded 'Vitamin B17' are related to the amygdalin compounds found in bitter almond seeds. However, these substances have been found ineffective as cancer treatments and are associated with a high risk of cyanide poisoning, leading to bans by regulatory bodies like the FDA.
What other names are associated with bitter almond oil?
Some other names include volatile oil of bitter almond, bitter almond volatile oil, and the Latin term Amygdalae Amarae Oleum. The processed, food-safe version is often called bitter almond essence or extract.
Why does bitter almond oil smell like marzipan?
The characteristic aroma of marzipan is derived from benzaldehyde, which is the main compound responsible for the scent and flavor of bitter almond oil. Therefore, the oil's scent is strongly reminiscent of marzipan.
Does sweet almond oil contain benzaldehyde?
Sweet almond oil contains only trace amounts of benzaldehyde and does not contain the toxic amygdalin found in bitter almonds. The vast majority of sweet almond oil is composed of beneficial fatty acids.
What are some industrial uses for benzaldehyde?
In addition to food and fragrance, benzaldehyde is used as a chemical intermediate in manufacturing various compounds, including dyes, cinnamic acid, and benzoic acid.
