Published February 1, 2013. From Cook's Country.
How do these packaged products compare to fresh egg whites—both in taste and performance?
When you need a lot of egg whites for a recipe, it’s tempting to grab a carton of egg whites sold in the supermarket dairy case or a canister of powdered egg whites in the baking aisle. But do these taste the same as fresh egg whites, and can you cook with them with comparable results? We bought four products (three liquid and one dehydrated) put out by national brands and made egg white omelets, meringue cookies, and angel food cakes, tasting them blind alongside samples made with egg whites from eggs that we cracked ourselves.
All four products were more or less acceptable in omelets (although the powdered whites were slightly grainy). But when it came to baking, fresh eggs produced taller angel food cakes and delicately crisp meringues, whereas egg white substitutes yielded shorter cakes and slightly harder, denser meringues.
Given that these products contain nothing but egg whites, what made the difference? The U.S. Department of Agriculture requires that liquid egg whites be pasteurized, a process that heats the whites enough to kill bacteria without cooking them. Powdered egg whites are made by evaporating water in a spray dryer. The substitutes can be safely added to uncooked frostings and drinks. But pasteurization changes the nature of the egg proteins enough to compromise their structure, especially in baked goods—a limitation that isn’t always mentioned on product labels. The heating process prematurely links the proteins so that they unfold and stretch less readily when whipped. As a result, they cannot hold the same amount of air or achieve the same volume as fresh egg whites. That’s why when we whipped the whites, one product needed 22 minutes to reach soft peaks, compared with just 6 minutes for fresh whites. Our top-ranked product is a convenient substitute for fresh whites in omelets, scrambles, and frittatas, and it makes satisfactory baked goods. Just keep in mind that it costs more than fresh whole eggs.