The wide range of products that yield the delicious smells and tastes of freshly baked goods is the result of a complex interaction of various ingredients and physical processes. Egg is a crucial component of many baked goods, due to its unique functional properties and the significant contribution it makes to structure, appearance, texture and taste.
By Sarab Sahi, Rheology and Texture Section Manager at Campden BRI
Around the world, the aroma of freshly made bread and other baked goods is irresistible to most people. The pandemic only appeared to accelerate the attraction towards these products, with demand for bread increasing 50% at one-point last year, further cementing it as one of the UK’s favorite staple foods.
Exquisitely simple, yet enormously complex, the egg is one of Nature’s marvels. It is a vital baking ingredient for a large number of products, such as cakes, pastries, meringues, macaroons, custard fillings, quiches and pancakes. But how vital is it in baked goods? Here we’ll investigate the many functions this ingredient offers in order to address this question.
Eggs consist of a clear white albumen, which comes from albus, the Latin word for ‘white’. Four alternating layers of thick and thin albumen contain approximately 40 different proteins, which are the main components of the egg white in addition to water.
The yolk contains less water and more protein than the albumen, some fat, and most of the vitamins and minerals of the egg. These include iron, vitamin A, vitamin D, phosphorus, calcium, thiamine, and riboflavin, and yolk is also a source of lecithin. Yolk colors range from just a hint of yellow to a magnificent deep orange, according to the feed and breed of the hen.
An examination of the functional properties of eggs is useful to understand how much they contribute to the baked goods we know and love today.
In cakes, muffins, cookies, pancakes, waffles, doughs and many other baked goods, whole eggs are used as a binder. Eggs are natural binders, helping hold all other baking ingredients together and increasing the viscosity of batters and doughs. Egg white has the capability to gel and is frequently used as a binding agent in many different prepared foods. Using more whites in a cake mixture will help create a fluffy, light baked product with good volume and texture; while using more yolks will create a denser baked good with a deeper, richer flavor.
Aeration is a critical function in the formulation of baked goods. It refers to the process of introducing gas into a liquid or viscous solution. Beaten whole eggs as well as egg whites on their own, are highly effective leavening agents, incorporating air into the dough or batter. As the air bubbles are trapped in the mixture, a foam is created, which will expand in the oven, causing cakes to rise, providing volume and a lighter texture.
Egg whites’ ability to make foods foam is due to complex interactions between the various proteins that make up egg white. The different protein components show a range of functionalities that affect both the tension between air-liquid interfaces as well as the viscosity of the liquid phase and it is this unique combination of properties that results in egg being such an effective raw material. The globulin proteins are highly surface active and they contribute to the formation of small bubbles when egg white is beaten, hence providing smooth texture to a cake or meringue. Egg whites can be whipped to produce foams that are six to eight times greater in volume. Another key protein is ovomucoid which gives egg white its viscosity and this slows the liquid draining out of foams thus making the foam more stable.
You can read the rest of this article in the March/April Issue of European Baker & Biscuit magazine, which you can access by clicking here.