These enzymes are found in plants of the genus Allium, such as garlic and onions. Alliinase is responsible for catalyzing chemical reactions that produce the volatile chemicals that give these foods their flavors, odors, and tear-inducing properties. Alliinases are part of the plant's defense against herbivores. Alliinase is normally sequestered within a plant cell, but, when the plant is damaged by a feeding animal, the alliinase is released to catalyze the production of the pungent chemicals. This tends to have a deterrent effect on the animal. The same reaction occurs when onion or garlic is cut with a knife in the kitchen.
Let’s just cut to the chase already: the soup has 44 cloves of garlic in it. 28 are roasted and then peeled, 18 peeled and then simmered, and somehow the outcome is subtle, but not boring. My 11-clove serving was heavenly, and with a glass of wine we fell back into that haze of garlic Ruth Reichl so aptly describes in Comfort Me With Apples after feasting on duck with garlic mosaics, fish wrapped in puffs of garlic pastry, lamb surrounded by garlic puree, arugula salad with garlic-rubbed croutons and poached figs in red wine with garlic meringues at Chez Panisse.
“If everyone ate more garlic, the world would be a happier place,” she says, and if this soup is any indication, I wholeheartedly agree.