At the very end of making a miso-lemon glaze in which to bake tofu last Sunday night, I realized that I had intended to include garlic in the mix. I quickly crushed a bunch of cloves, pressed them into the tofu, and closed the oven door. When I checked on dinner half an hour later, I found the garlic a bright, Easter Basket-grass green. What the hell?
Turns out that crushing garlic releases an enzyme named Alliiase which in turn goes to work on a sulfurous compound named Allicin. Allicin is garlic’s primary defense against pests and also the chemical basis for humanity’s long reliance on garlic to bolster health and fend of diseases. When the flesh on the garlic bulb is torn, the Allicin breaks down into other sulfurous compounds, and when those compounds mix with an acid they form carbon-nitrogen rings that link together in various combinations to form molecules. These molecules absorb particular light wavelengths and the four-ringed molecule ends up looking green. Busted Allicin mixed with citric acid results in a molecule closely related to tetrapyroole: chlorophyll. Groovy.