A plant is a chemical universe unto itself.
Even an innocuous blade of grass produces more natural compounds than we can properly appreciate. Some compounds contribute to the plant's growth and development. Some combine to attract pollinators and seed dispersers. And yet others exist to deter predators and pathogens. These complex systems of chemicals all work together to help the plant achieve one thing: survival.
The artichoke doesn't need to rely on its chemical arsenal for protection from predators; nature has bestowed it with cellulosic armor and barbs for that purpose. But even those haven't deterred the indomitable human curiosity and our insatiable appetite once we discovered that beyond its armament, there is something good to eat inside. Our attraction to the artichoke's buried heart is a chemical one; phenolic, to be precise.
Plant chemistry, simplified
All living organisms produce compounds that are essential to life. In plants, these can be divided into two metabolic groups:
Primary metabolites support growth, development and reproduction. Included in this group are carbohydrates, amino acids, polymers, lipids, etc.
Secondary metabolites are organic compounds of low molecular weight (often produced at less than 1% dry weight) that are not vital to growth but allow plants to attract pollinators and defend itself from herbivores and pathogens, but not from humans. Often, these compounds are what attract us to certain plants in the first place— they define its flavor and aroma. Secondary metabolites can be classified into three groups: Alkaloids, Terpenoids, and Phenolics.
Phenolic activity in artichokes
Anyone who has cut into an artichoke has witnessed oxidation; a reaction that takes place when phenolic compounds are combined with enzymes (through cutting or bruising) and exposed to oxygen, turning the exposed surface brown. Applying acid by rubbing with a lemon wedge only slows down the reaction. The only way to prevent it is to cut off its exposure to oxygen by submerging in water or vacuum sealing. Heating to temperatures above 212F/100C destroys the enzyme.
phenolic oxidation/ reaction to acid— both cups contain artichoke tea; the one on the right changes color after adding a few drops of lemon juice
Phenolic compounds are a rich source of phytochemicals (nonessential nutrients that are beneficial to health) such as antioxidants, flavonoids, and tannins. Artichokes are a primary source of cynarin, a compound that is believed to promote good health, including liver detoxification. Cynarin's ability to lower cholesterol was first documented In the 1970's, and many promising studies have taken place since.
Artichokes are notoriously difficult to pair with wine, thanks to cynarin and chlorogenic acid. These two phenolic compounds inhibit sweet receptors on our tongues, causing subsequent ingestion of foods or liquids to taste sweet. This taste perversion is similar to the one produced by miraculin, a protein found in miracle fruit, though it is significantly more short-lived and occurs only in a portion of the population, suggesting that it may be a genetic predisposition.
Cynarase, another enzyme found in artichokes, is believed to aid in digestion because of its ability to curdle milk. In parts of Europe and North Africa, coagulating milk for cheese with cardoon (a close relative of artichoke) is a long-standing tradition that is still carried out today.
Over a decade ago, while in Portugal, I learned that a popular cheese, Azeitao, is made from unpasteurized sheep's milk curdled with cardoon. It wasn't until earlier this year that I discovered that cynarase was responsible. As artichokes came into season, I began experimenting with their various parts, cooked in milk, with no success— lots of artichoke-flavored milk, but no curds. It wasn't until further research revealed that it is the mature thistle flower that is used to form milk curds that I tried again with the isolated choke (the undeveloped flower). Finally, I was able to produce enough curds to press into a small fresh cheese. These curds were very small, scarce, and soft, producing an impossibly fragile, but wonderfully herbaceous-flavored cheese. I haven't had much luck growing artichokes in Zone 5, but I'm willing to try again, if only to harvest the flowers. Barring that, there are other alternatives to explore— other flowers in the Cynareae tribe that do grow in my zone.
I wanted to build a dish around this very small, fragile, and delicious cheese that would represent all of the interesting things that I've learned about the artichoke. I started by pairing the milky cheese and the tender inner scales and ribbons of vegetal artichoke heart with the flavor of cherries. The ephemeral cherry blossoms hearken the nature of the artichoke-as-flower and whisper softly of benzaldehyde, while a soft gel of Villa Manodori Dark Cherry Balsamico gives the dish alacrity and vibrance. The artichoke tea, made by steeping the outer scales in boiling water, exhibits phenolic oxidation by changing from bright green to yellow when poured over the acidic cheese and gel. The herbaceous tea has a bitter edge that not only disappears, but is made sweet after taking a bite of the taste-altering heart.
artichoke
cynarase-curdled raw milk cheese
Villa Manodori Dark Cherry Balsamico
artichoke tea
cherry blossom
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