Aquafaba [ah-kwuh-fah-buh], or chickpea brine, is the liquid from canned chickpeas, used as an egg substitute because of its function as an emulsifier, leavening agent, and foaming agent. Vegan baker Goose Wohlt coined the term aquafaba (‘bean liquid’) to describe the substance, which French chef Joël Roessel discovered could be used as substitute for egg whites in recipes. Aquafaba has been used to create meringues, macarons, nougat, and other products that normally require the use of eggs, making them suitable for people with egg allergies, vegans, and lacto-vegetarians.
There is currently no scientific consensus on the chemical properties of aquafaba and why it mimics egg whites so effectively. Seed proteins, including albumins and globulins, as well as soluble fibers, sugars, and glycosides have been proposed as contributing to the similarity. Roessel purports that the most likely agent that causes the liquid to foam are saponins, plant molecules containing a combination of hydrophobic (fat-soluble) and a hydrophilic (water-soluble) components.
The Daily Omnivore 