Cracking the recipe for perfect plant-based eggs

An egg is an amazing thing, culinarily speaking: delicious, nutritious, and versatile. Americans eat nearly 100 billion of them every year, almost 300 per person. But eggs, while greener than other animal food sources, have a bigger environmental footprint than almost any plant food—and industrial egg production raises significant animal welfare issues.

So food scientists, and a few companies, are trying hard to come up with ever-better plant-based egg substitutes. “We’re trying to reverse-engineer an egg,” says David Julian McClements, a food scientist at the University of Massachusetts Amherst.

That’s not easy, because real eggs play so many roles in the kitchen. You can use beaten eggs to bind breadcrumbs in a coating, or to hold together meatballs; you can use them to emulsify oil and water into mayonnaise, scramble them into an omelet or whip them to loft a meringue or angel food cake. An all-purpose egg substitute must do all those things acceptably well, while also yielding the familiar texture and—perhaps—flavor of real eggs.

Today’s plant-based eggs still fall short of that one-size-fits-all goal, but researchers in industry and academia are trying to improve them. New ingredients and processes are leading toward egg substitutes that are not just more egg-like, but potentially more nutritious and better tasting than the original.

In practice, making a convincing plant-based egg is largely a matter of mimicking the way the ovalbumin and other proteins in real eggs behave during cooking. When egg proteins are heated beyond a critical point, they unfold and grab onto one another, forming what food scientists call a gel. That causes the white and then the yolk to set up when cooked.

Eggs aren’t just for frying or scrambling. Cooks use them to bind other ingredients together and to emulsify oil and water to make mayonnaise. The proteins in egg whites can also be whipped into a foam that’s essential in meringues and angel food cake. Finding a plant-based egg substitute that does all of these things has proven challenging.

That’s not easy to replicate with some plant proteins, which tend to have more sulfur-containing amino acids than egg proteins do. These sulfur groups bind to each other, so the proteins unfold at higher temperatures. As a result, they must usually be cooked longer and hotter than ones in real eggs.