What are the active ingredients in black garlic?

January 14, 2026 •

3 min read

Recent research reveals that the aging process dramatically transforms fresh garlic's chemical profile, increasing its antioxidant content significantly. The key active ingredients in black garlic, such as S-allyl-cysteine (SAC) and polyphenols, are the result of this complex Maillard reaction, yielding unique flavor and health properties.

Quick Summary

The aging process of black garlic increases beneficial compounds like S-allyl-cysteine, flavonoids, and polyphenols, while decreasing allicin. This transformation gives black garlic unique antioxidant and anti-inflammatory properties, distinguishing it from its fresh counterpart.

Key Points

S-allyl-cysteine (SAC): The most prominent active ingredient in black garlic, which is a stable, water-soluble, organosulfur compound formed during the aging process.
Increased Antioxidants: Black garlic contains significantly higher levels of antioxidants, including polyphenols and flavonoids, compared to fresh garlic due to the Maillard reaction.
Low Allicin Content: Unlike fresh garlic, black garlic has a much lower concentration of allicin, the unstable sulfur compound responsible for the pungent odor and taste.
Anti-inflammatory Properties: The compounds in black garlic, especially SAC, contribute to its anti-inflammatory effects by helping to regulate inflammatory pathways.
Enhanced Bioavailability: The aging process may make the nutrients and active compounds in black garlic easier for the body to absorb.
Maillard Reaction Products: Other compounds, such as 5-Hydroxymethylfurfural (5-HMF), are created during the Maillard reaction, contributing to the distinct flavor and health profile.
Higher Amino Acid Concentration: The aging of garlic alters its amino acid composition, with some amino acids like arginine increasing significantly.

The Maillard Reaction: A Chemical Transformation

Black garlic is created by aging fresh garlic bulbs under controlled heat (typically 140°F to 190°F) and high humidity for several weeks. This process is not fermentation but rather a non-enzymatic browning reaction known as the Maillard reaction. This chemical process, which also occurs when searing meat or toasting bread, converts sugars and amino acids in the garlic, causing it to turn black and develop its sweet, molasses-like flavor and chewy texture. Critically, this reaction also transforms the garlic's original active compounds, producing new ones and altering their concentrations.

S-Allyl-Cysteine (SAC): A Potent and Stable Compound

One of the most significant changes during the aging process is the substantial increase in S-allyl-cysteine (SAC). Unlike allicin, the primary active compound in fresh garlic that is volatile and unstable, SAC is water-soluble and far more stable. Studies have shown that black garlic can contain significantly higher levels of SAC compared to fresh garlic, with some reporting increases as high as 16-fold. This compound is heavily researched for its potent antioxidant and anti-inflammatory effects.

Increased Antioxidant Compounds

The Maillard reaction produces a wide array of new compounds and boosts the concentration of others, resulting in a much higher antioxidant capacity in black garlic than fresh garlic. This includes significant increases in total polyphenols and flavonoids. These antioxidants help neutralize free radicals in the body, protecting cells from damage and reducing oxidative stress.

The Fate of Allicin

Fresh garlic is known for its strong, pungent smell and taste, which comes from the sulfur compound allicin. During the aging process, allicin is almost completely broken down, which is why black garlic lacks the sharp flavor and odor of raw garlic. The allicin is converted into other compounds, including the more stable and beneficial S-allyl-cysteine. This absence of allicin also makes black garlic easier for many people to digest.

Other Bioactive Compounds in Black Garlic

Beyond SAC, the active ingredient profile of black garlic is complex and includes a variety of other beneficial compounds.

Flavonoids: These plant-based compounds have antioxidant properties and increase during aging.
Polyphenols: The total phenolic content of black garlic is markedly higher than fresh garlic, contributing to its enhanced antioxidant activity.
Organosulfur Compounds (OSCs): While allicin is reduced, other OSCs like diallyl sulfides (DAS), diallyl disulfides (DADS), and diallyl trisulfides (DATS) are also present.
5-Hydroxymethylfurfural (5-HMF): This compound is a product of the Maillard reaction and has been studied for its potential health benefits.
Amino Acids: The aging process causes a change in the concentration of amino acids, which also contribute to the altered flavor and nutritional profile.

Comparison Table: Fresh Garlic vs. Black Garlic


Characteristic	Fresh Garlic	Black Garlic
Processing	Raw	Aged in heat and humidity
Color	White to cream	Dark brown to black
Texture	Firm, juicy	Soft, chewy, jelly-like
Flavor	Pungent, sharp	Sweet, umami, molasses-like
Allicin Content	High	Trace amounts
S-Allyl-Cysteine (SAC)	Low	High
Antioxidants	Moderate	Very High
Digestibility	Can cause indigestion	Easily digested

Conclusion

The active ingredients in black garlic are fundamentally different from those in fresh garlic, thanks to the Maillard reaction that occurs during its aging process. This transformation reduces the pungent, unstable compound allicin and significantly increases the concentration of stable, beneficial compounds, most notably S-allyl-cysteine (SAC), flavonoids, and polyphenols. This change results in a distinct flavor profile and a superior antioxidant capacity, solidifying black garlic's reputation as a functional food with a unique health-boosting composition. These properties make black garlic a valuable ingredient for both culinary applications and as a dietary supplement. For further reading, an extensive review on black garlic's bioactive compounds and health effects can be found on the MDPI website(https://www.mdpi.com/1422-0067/25/3/1801).

Frequently Asked Questions

Fresh garlic's primary active compound is allicin, which is highly unstable and responsible for its pungent odor. In black garlic, the aging process converts allicin into more stable, potent, and water-soluble compounds, most notably S-allyl-cysteine (SAC).

The aging process, also known as the Maillard reaction, breaks down the unstable allicin in fresh garlic and synthesizes new compounds. This leads to a substantial increase in antioxidants like SAC, flavonoids, and polyphenols, while also altering the overall amino acid profile.

Yes, black garlic has been shown to have significantly higher levels of antioxidants than fresh garlic. The aging process creates new antioxidant compounds and increases the concentration of existing ones like polyphenols, providing enhanced health benefits.

S-allyl-cysteine (SAC) is a stable, water-soluble organosulfur compound that is found in high concentrations in black garlic. It is a potent antioxidant and is believed to contribute to black garlic's anti-inflammatory, heart-healthy, and neuroprotective properties.

No, despite being commonly referred to as fermented, the process of making black garlic is an aging process that relies on the Maillard reaction, not microbial fermentation. This reaction involves sugars and amino acids and is what causes the darkening and flavor changes.

The conversion of allicin during the aging process is what eliminates fresh garlic's sharp, pungent flavor. This allows the natural sugars to concentrate and react with amino acids, resulting in black garlic's characteristically sweet, savory, and umami-rich flavor profile.

The health benefits of black garlic are primarily derived from its unique profile of bioactive compounds, particularly the high antioxidant content. These compounds collectively contribute to its reported antioxidant, anti-inflammatory, and other therapeutic effects.