allicin

Whole garlic barely smells of anything. Cut or crush it and the smell arrives all at once, because it did not exist a moment before: alliinase, held in the vacuole, meets alliin, sitting separately in the cytosol, and the two react the instant a cell wall breaks. Chester Cavallito and John Bailey isolated the product, allicin, in 1944 and called it the antibacterial principle of garlic; Arthur Stoll and Ewald Seebeck found the precursor alliin four years later and worked out the enzyme the year after. In this library allicin forms the moment garlic is minced or crushed, in four recipes: a bulgur-and-zucchini dish, a lentil-and-pasta dish, a curry, and a molokhia stew.

Allicin is C₆H₁₀OS₂, formed when two molecules of allylsulfenic acid condense after alliinase cleaves alliin. The kinetics are fast: at room temperature the reaction runs about ninety-seven percent complete within thirty seconds, and a ten-gram clove yields at most around five milligrams. It does not last. Allicin decomposes on its own within hours into diallyl disulfide, trisulfide, vinyldithiins and ajoene, and heat accelerates the same breakdown, so long-cooked garlic smells rounded and sweetish because the nose is catching that wreckage, not allicin itself. Heat also disables the enzyme before it can act: dropped whole into boiling water, alliinase activity is gone within about two minutes, and a clove's interior reaches roughly ninety-five degrees within four, so a whole cooked clove never gets the chance to make much allicin at all.

The burn is not incidental. Allicin is a cytotoxin, the defense of a plant with no other way to stop being eaten, and raw garlic applied to skin causes actual burns. Swallowed in food, the evidence is real but modest: a meta-analysis of eleven trials found garlic lowered systolic blood pressure by around 4.6 mmHg against placebo, more in people who were already hypertensive, and a larger synthesis across 108 trials found improvements in triglycerides, cholesterol and glucose alongside explicitly no effect on body weight. No trial has shown it prevents a heart attack or a stroke, and measured active content varies by a factor of seven and a half between commercial supplements. Four recipes in this library trace it to garlic, crushed or minced and cooked just briefly, thirty seconds to a minute, to keep its edge rather than lose it.