Many baked goods rely on proteins to develop structure and height. For simple products such as bread and buns, the gluten from wheat typically suffices. Sweet goods, on the other hand, contain heavy ingredients such as sugar, shortening and inclusions like chocolate, fruit and nuts. This is too much for a gluten matrix to handle on its own, and that’s where egg proteins enter the equation.
“Eggs are a very complex source of fats and proteins that can be used in hundreds of applications,” said Mindi McKibbin, director of research and development, Rembrandt Enterprises, Inc.
Egg products are dried, frozen or liquid forms of whole eggs, whites only or yolks only. Sometimes these formats include additional ingredients to improve functionality, expand applications or even provide cost savings.
Eggs also provide more than 20 desirable functions ranging from foaming to ingredient binding to thickening. No single replacement ingredient can perform all the same functions as eggs.
“Besides for nutritive value, egg ingredients provide important functional properties to baked goods,” said Bill Gilbert, principal food technologist, Cargill. “It’s impossible to replace eggs with any single ingredient and still provide similar nutrition and function. Yet, some bakers prefer formulating vegan and seek out replacers. Economics is also another consideration.”
The good news for bakers is that the egg supply currently is abundant and pricing attractive. This is also true for cage-free eggs, where players in the natural foods space tend to gravitate.
That said, there are real reasons why bakers might prefer egg replacers or at least have formulations on hand that replace some or all eggs with other functional ingredients. One reason for replacing eggs is to remove a common allergen from the recipe. Another is that eggs and egg products have had numerous supply and demand challenges over the years, and it’s always better to be prepared than be scrambling.
First came the egg
Traditionally formulated baked foods, especially sweet goods, rely on eggs for a long list of sensory attributes. This has been shown in an extensive body of research recently conducted by independent third-party firm CuliNex L.L.C.
The research details both the analytical and slightly more subjective sensory results of experiments comparing eggs with egg replacers in a variety of applications. Most, if not all, of the applications tested relied on the functionality of eggs or egg replacers for appearance, texture, mouthfeel and taste. Certain pie fillings, for example, need eggs or egg replacers with similar functionality for optimal eating quality. The changes to pie fillings with reduced egg content were noticeable, according to the researchers.
Angel food cake is another example. This highly aerated product obtains its color, rise, texture and flavor from eggs. When they are removed or replaced in angel food cake, the batter’s specific gravity, appearance, height and flavor are negatively affected, according to the study.
CuliNex tested baked goods, including sponge cake, yellow batter cake, muffins, sugar cookies, chocolate chip cookies, cheesecake, brownies, sweet dough and frozen waffles, all of which rely on eggs for similar characteristics.
Elisa Maloberti, director of egg product marketing, American Egg Board, said some types of applications rely more on eggs than others.
“When a product relies upon a higher percentage of eggs for its functional and organoleptic characteristics, it will suffer a greater impact when eggs are removed,” she said.
In cheesecake, for example, the standard is 12.5% whole eggs, Ms. Maloberti said. For sugar cookies, it’s about 3.8%.
“When the research team tested eggs versus various replacement products in cheesecake,” she said, “they reported that ‘except for water activity, all areas of cake quality were negatively affected, especially flavor and texture.’”
With sugar cookies, when eggs were replaced or removed the difference was recorded as “slight but noticeable,” the study, sponsored by the American Egg Board, found. Areas most negatively affected in sugar cookies included the color/appearance, aroma, flavor and texture.
“Consistently throughout most of the study, researchers found that tasters unanimously preferred the control, or gold standard formula made with eggs, to the test formulas,” Ms. Maloberti said.
Some bakers do use eggs in artisan and specialty bread formulas, as they contribute to a richer flavor and softer texture. Use is, however, usually cost-prohibitive due to price fluctuations in standard white pan bread and buns.
Some of the physical functions eggs perform in baked goods are aeration, binding, emulsifying and dough strengthening. They also assist with maintaining moistness and, thereby, extend shelf life. Depending on the egg ingredient used, color and flavor also may be influenced. When identifying a replacer, it is critical to know what functions the ingredient must perform.
Cracking egg chemistry
The egg yolk and white contribute very different characteristics to baked goods, and understanding how they work is key to finding potential replacers.
“The egg white is the main component in strengthening, as it contains a majority of the protein in the egg,” said David Guilfoyle, group manager bakery, fats and oils, DuPont Nutrition & Health.
Albumin is the egg white’s primary protein source, and upon heating, the albumin structure denatures to create a special gel strength that most other proteins do not have. This strength is important, especially in cakes, as the batter is heated, the volume increases, and the aerated albumin gel structure begins to denature and the leavened structure is set.
“Potato isolate protein and milk whey without lactose are two ingredients that have nearly similar gel strength to egg,” Mr. Guilfoyle said. “Other proteins set too quickly, creating a dense structure, or begin to collapse due to the weight of the ingredients in the formulation before the structure can be set.”
Eggs whites are also the powerhouse behind aeration, or creating foams. As the egg white is whipped, air gets trapped within the albumin, which stretches out with protein-coated air cells that become stable enough to hold the heavy ingredients.
“As the foam is heated, the protein-coated air cells expand and the structure lifts, and upon reaching a certain temperature, the foam structure sets and holds the bound ingredients in place,” Mr. Guilfoyle said. “We offer various hydrocolloids that can aerate similarly to egg whites.”
The egg yolk contains the emulsifier component lecithin, which allows water and oil to become miscible, creating either an oil-in-water or water-in-oil emulsification. If this is the function that needs replacing, it is possible to source lecithin from plants such as soybean or sunflower.
“They are all equally as functional as the lecithin from egg,” Mr. Guilfoyle said.
Natural Products, Inc., manufactures soy-based egg and milk replacement systems, which tend to be hydrophilic, even more so than eggs. Jon Stratford, sales and marketing manager, Natural Products, said the company’s egg replacers are formulated to replace whole egg powder at a 1:1 ratio.
“However, because the soy tends to bind so much water, it is not uncommon for our customers to find they need to reduce our product slightly, versus the quantity of eggs that were being used, to avoid having to add more water to their formulation,” Mr. Stratford said. “On the other hand, in some cases, it might be an advantage to add a bit more water, as that can improve the shelf life of fresh-baked products.”
The water-binding attribute dictates the most suitable applications.
“Our egg replacers also provide emulsification,” Mr. Stratford said. “Applications where eggs mainly provide emulsification tend to work best with our egg replacers.”
Hatching a replacement plan
In real-world applications, the allergenic nature of egg and dairy ingredients can be a hurdle for some manufacturers according to a story about a hamburger bun as told by Mr. Guilfoyle.
“At the time, brioche was coming in as a ‘new’ style of bread, and the restaurant chain wanted to have a signature bun that was brioche-style,” Mr. Guilfoyle explained. “Brioche is high in egg and dairy [butter and milk] and very expensive. The various high-speed bakeries supporting the restaurant chain refused to put any formula in their production that contained the egg and dairy allergens. This created some issues.”
Understanding the functionality of eggs and dairy in bread, Mr. Guilfoyle was able to reformulate with ingredients that provided the mouthfeel and flavor of a brioche-style bun without using the eggs or dairy products. Alginates provided the mouthfeel component, and they also gave the finished baked crumb structure strength to hold up to the heavily loaded burger and condiments. When alginates are added at 0.10% to 0.20% (baker’s per cent), they provide strength and volume to baked goods.
Artisan bread varieties are some of the more challenging products in which to replace eggs.
“It’s easiest to find solutions for products like cookies, pancakes and muffins, where eggs are less critical to the finished product,” Mr. Gilbert said. “In other product applications, where eggs are critical to functions like aeration and structure, Cargill has developed functional systems that mimic the different aspects of eggs.”
These functional systems may provide cost savings by replacing up to 50% of the eggs in the formula, often with little or no additional changes required. For example, modified starches mimic the processing and emulsifying properties of eggs, providing essential structure and texture in cookies, pancakes and muffins.
“Modified starch is especially suited for replacing up to 25% of liquid whole eggs in cakes and pound cakes, 50% in muffins, 50% to 100% in pancakes, and 50% of egg solids in cookies,” Mr. Gilbert said. “Soy flour can be used to replace 25% of liquid whole eggs in muffins, and 25% to 50% in both cookies and pancakes. Soy flour helps maintain moisture and acts as a fat mimetic.”
Cargill works with bakers to create customized texturizing systems for egg replacement. In addition to modified starch and soy flour, other ingredients used in the systems include lecithin, mono- and diglycerides, potato protein and carrageenan.
Fiberstar, Inc. offers a citrus fiber with high pectin content that functions as an egg replacer. The added benefit is that it also contributes fiber to the formula. Kurt Villwock, director of R&D, Fiberstar, said citrus fiber contains both soluble (pectin) and insoluble fiber and is made using a patented process that opens the fiber structure to create high surface area.
“This fibrous composition tightly entraps and locks in water molecules and oil droplets, providing high-water holding and emulsification properties,” Mr. Villwock said.
Citrus fiber typically is used to extend eggs rather than fully replace them. It works best in muffins, layer cakes and cookies. Combined with other hydrocolloids, it can work synergistically to replace the whole egg in gluten-free muffins and cakes.
Addition of as little as 0.2% citrus fiber can compensate for the removal of eggs in a waffle or crepe. It is simply dry blended with the flour, and the product is dosed and cooked in the same manner as a conventional full-egg product.
“The nice thing about using citrus fiber in an egg replacement strategy is that it provides a nice mouthfeel that, in a mixture, complements other ingredients that might otherwise cause textural defects,” Mr. Villwock said. “Citrus fiber also increases the cohesiveness of doughs, which is beneficial for machinability.”
A number of citrus fibers serve as egg extenders on the market. They vary in the way they are processed and their final composition, which in turn influences functionality and labeling claims. Citrus fiber is perceived to be clean label and is acceptable in ingredient statements, especially in baked goods containing fruit bases.
Nigel Weston, vice-president, R&D, J&K Ingredients, said egg replacers allow bakers to control their ingredient costs over the long term.
“Eggs are currently very inexpensive, but traditionally they are amongst the most expensive ingredients in baked goods,” he said.
Cost savings, risk management and reliability of supply are some of the biggest benefits associated with egg replacers. In recent years, egg prices have been highly volatile. In 2014, albumen prices spiked to $17 per lb. One year later, the 2015 avian influenza crisis drove egg prices up to $20 per lb.
However, even in a stable price market, Mr. Gilbert said Cargill customers confirm that the savings associated with egg replacement solutions are significant. Bakers must weigh the functional benefits of eggs and the quality they impart on finished products vs. the potential cost savings in formulation.