Alliin, Alliinase and How Garlic Extract Is Standardised

The Plant's Own Design

Garlic's chemistry is a defence system, and understanding it as one makes everything else follow.

An intact clove stores alliin — S-allyl cysteine sulphoxide, a stable, odourless sulphur amino acid — in the cell cytoplasm. Separately compartmentalised sits the enzyme alliinase.

Nothing happens while the tissue is intact. Damage it — an insect, a knife, a tooth — and the compartments rupture, alliinase reaches alliin, and allicin is produced within seconds. Allicin is the plant's chemical response to being eaten, and its pungency is the point.

Read the last row. That is what is in your drum.

Why "Allicin Content" Cannot Be Specified

It follows directly. A dry extract is made from garlic that was processed and dried; whatever allicin formed during processing has largely decomposed, and the intact starting material never held any.

So an allicin content figure on a dry powder is either near-zero (if honestly measured) or an artefact of how the sample was prepared for assay. Neither is a specification.

Basis One: Alliin

Alliin is a defined compound, stable, present in the material, and assayed by HPLC against a reference standard. It behaves like a well-mannered marker — specific, reproducible, comparable between laboratories.

Its limitation: it tells you about the precursor only. A powder with good alliin but heat-killed alliinase will produce little allicin, and the alliin figure will not reveal that.

Basis Two: Allicin Yield

Allicin yield — allicin potential, or allicin-releasing capacity — measures how much allicin the material actually generates when the reaction is run under stated, controlled conditions.

Why it is the more informative figure: it tests both halves of the system. Precursor and enzyme together. A material can only produce a good yield if it has adequate alliin and functional alliinase.

The essential caveat: the conditions must be stated. Yield depends on the buffer, pH, temperature and reaction time used. A yield figure without conditions is not comparable between suppliers — the same portability problem we describe for class assays such as gymnemic acids, arriving here by a different route.

Requiring alliinase activity as a separate reported parameter adds further resolution.

The Acid-Lability Problem

The point where a correct specification meets an incorrect format.

Alliinase is acid-labile. Gastric acid inactivates it. So the reaction your yield figure measured in a laboratory buffer may not occur in a stomach.

Consequences:

1. An uncoated oral format substantially under-delivers against its yield figure.
2. Enteric coating carries the material past the stomach so the enzyme survives to act — which is why serious allicin-yield products use it.
3. A yield claim on a gummy, beverage or chewable is difficult to defend, because none of those can be enteric-coated.

The enteric coat is therefore part of the specification's meaning, not a delivery preference.

Basis Three: Aged Garlic and S-Allyl Cysteine

A different chemistry that sidesteps all of the above.

Aged garlic extract is produced by prolonged maturation, during which garlic's reactive sulphur compounds convert to stable, water-soluble derivatives. The principal marker is S-allyl cysteine (SAC).

Properties that follow:

• No allicin chemistry — no alliinase dependence, no acid lability, no enteric requirement.
• Largely odourless, which opens formats conventional garlic cannot enter.
• Stable and water-soluble.
• SAC is a defined compound assayed by HPLC — a clean, portable specification.

SAC figures and allicin-yield figures describe different chemistries and must not be compared.

Heat Is a Process Parameter, Not a Detail

Because alliinase is a protein, heat denatures it. Any processing step applying temperature — drying in particular — trades allicin yield for throughput.

Two practical consequences:

1. A supplier's yield figure is a readout of their drying discipline. Consistently good yield indicates gentle, controlled processing.
2. Warehouse heat continues the damage. Yield can fall in storage while alliin holds — so re-test long-held stock on yield, not alliin.

Writing a Garlic Specification That Holds

1. Declare the grade chemistry — alliin, allicin yield, or aged/SAC.
2. Never specify allicin as an as-is content.
3. State alliin NLT X% by HPLC, dry basis.
4. State allicin yield NLT X ppm with the assay conditions.
5. Require alliinase activity reported on yield grades.
6. Confirm the format supports the basis — enteric for yield claims.
7. Specify storage conditions in the purchase terms, since heat degrades the enzyme.

When Two Laboratories Disagree

1. Same yield conditions? Overwhelmingly the most common cause on garlic.
2. Was allicin measured as content or as yield? Entirely different numbers.
3. Same sample handling? Grinding a sample before assay starts the reaction.
4. Does alliin agree? It is a stable defined compound by HPLC — if alliin matches but yield diverges, the difference is enzyme activity or method, which is itself informative.

SV Botanica assays alliin by HPLC, determines allicin yield under stated conditions with alliinase activity reported, and supplies S-allyl cysteine standardised aged grades. See the garlic extract product specification, or the buyer's guide.