Protein: Baker's Building Blocks
June 1, 2011
by Donna Berry
In case you haven’t noticed, food marketing has once again entered a “minus” stage where an increasing number of content claims on packages address what the product does not contain instead of what it does. Examples include trans fat free, no added sugar and no artificial dyes or colors. Positive claims such as “made with whole grains” and “vitamin fortified” continue to be made, but the “free of” marketing jargon is filling up the front of food packages.
The one exception is protein. Marketers of all types of foods and beverages recognize that consumers value the powers of protein, which range from satiation to muscle recovery. Little do consumers know that proteins, specifically animal-sourced ingredients such as eggs and dairy, are also powerful formulating tools — especially for bakers.
“Proteins derived from milk or egg can play different roles in baked goods,” said Soren Norgaard, bakery technical sales manager, Arla Foods Ingredients, Basking Ridge, NJ. “In some products, the protein helps form structure due to its ability to form a gel. This is typically seen in products such as pound cakes and muffins where the specific gravity of the batter is high, and the majority of the raising ability of the cake comes from the gas released by the leavening agent used in the formulation. In this case, the protein helps stabilize the structure by creating volume, resilience and desirable eating quality.
“In low-density systems such as sponge cake, the proteins typically have more than one duty to perform,” he continued. “They help with the aeration of batter during the mixing process, and later during baking, they help stabilize the cake structure by entrapping some of the air inside the cake.”
Like flour, eggs are traditional structure-building agents in grain-based baked goods, but they do more than that. “Eggs perform more than 20 different functions, enabling bakers to eliminate the use of additives or additional ingredients, thus simplifying ingredient statements,” said Dan Vance, project manager, R&D, Michael Foods Egg Products Co., Gaylord, MN. These functions include coagulation and emulsification, both of which contribute to the structure of baked goods.
On a solids basis, whole eggs are about 50% protein and 40% fat. Whites consist almost entirely of protein, whereas yolks are about half fat and one-third protein. Because whole eggs contain more than 40 different proteins, some unique to the white and others to the yolk, it’s no wonder that whole eggs, whites and yolks all function differently in baked goods.
One of the most important contributions that egg proteins make to baked goods is to trap air, thus forming a food foam. This creates volume and produces a baked product with desirable texture, mouthfeel and appearance. These attributes vary based on egg product type.
For instance, a pound cake is denser than a sponge cake, which is why egg yolks are often used in pound cake. On the other hand, beaten whole eggs contribute more volume and a lighter texture to sponge cake. The aeration achieved in still lighter-textured baked goods such as angel food cake comes from egg whites. To appreciate how egg products accomplish these effects of height, volume and stability, it is necessary to understand protein structure and how they can change from liquid to solid.
This change of state — from liquid to solid or semi-solid, known as either coagulation or gelation — results when the structure of egg proteins is altered by whipping, heating or both. The coagulation process involves the denaturation of protein, the point at which proteins lose their native, water-soluble structure and become insoluble. During this process, proteins form a three-dimensional network that traps air and moisture, as well as interacts with gluten, thereby essentially building the baked good. In essence, proteins create cells with the cellular wall composed of proteins and the cell contents being air or moisture. A stable cellular structure prevents excess moisture loss, which contributes to the humectancy, or moistness, of the product, a sign of freshness throughout its shelf life.
The differences in the foaming and coagulation properties of whole eggs, whites and yolks lie in the fact that yolks barely contain any of the powerhouse foam-producing and stabilizing proteins found in the whites: conalbumin, globulin, ovalbumin and ovomucin. The protein in yolks is almost all lipoprotein, which can also trap air, just not as notably as the proteins of the whites. Lipoproteins are better suited for emulsification, which also affects structure and stability of baked goods.
“Egg yolk is renowned for its emulsification properties. Egg yolks allow fats to stay dispersed in water and water to stay dispersed in fats. This promotes thickening and product stability,” Mr. Vance said. “These emulsification properties contribute to a smooth, creamy texture. Further, the lecithin found in egg yolks also enhances texture, because lecithin reduces moisture loss, which ensures a soft, tender crumb.”
Egg proteins also assist with topical applications on baked goods. “By mixing eggs with cream or milk, bakers can create different types of glazes,” Mr. Vance said.
The proteins bind together and create a seal. “The glazes lock in moisture in bakery foods and also bind seeds, crumbs, nuts and other coatings to the baked foods’ crust,” he added.
Foods formulated with egg products contain all the nutrition originally found in the egg product, including high-quality, complete protein, trans-fatty-acid-free mono- and polyunsaturated fats, vitamins, minerals, and other highly bioavailable nutrients with recognized health and wellness benefits.
A number of bakers now market egg-free baked goods for people who avoid eggs for religious or medical reasons.
“The Hindu religion forbids the consumption of eggs; therefore, bakeries serving these communities are looking for alternative sources of high-quality proteins,” said Peter Gutierrez, vice-president, global ingredient sales, Agri-Mark, Inc., Lawrence, MA. “They find this in a number of dairy ingredients. In addition, there are consumers who are allergic to eggs but have no problem with dairy proteins.”
Dairy ingredients provide multiple benefits in bakery applications, including browning, emulsification, foaming, moisture retention and protein fortification, and thus find use in a wide variety of baked goods, according to Sharon Gerdes, senior account manager, US Dairy Export Council, Arlington, VA. “Choosing the optimal dairy ingredient for a specific application requires a good understanding of the composition and functionality of each specific ingredient,” she said.
For example, sweet whey was long considered a byproduct of the manufacturing process of certain cheeses, including popular Cheddar and Swiss varieties. Bakers learned to appreciate sweet whey as an economical replacement for some of the sugar in formulas, as well as a source of tenderizing proteins. Then things changed, and cheese makers learned they could process this byproduct into ingredients that command a higher price — such as whey protein concentrate (WPC) and whey protein isolate (WPI) — and thus receive a better return on their investment.
“There are only a few sweet whey processing facilities still in operation, which means supply is low but demand by bakers has not changed,” Mr. Gutierrez said. “Many bakers are turning to whey permeate, which is a low-cost alternative to sweet whey in many baking applications.”
Whey permeate is usually a byproduct of the production of white cheeses. After the ultrafiltration of fresh fluid whey from these cheeses, an ingredient portion remains from which the whey-based material is manufactured. This whey permeate has a slightly higher lactose content and lower protein content than sweet whey but, for many bakers, does the same trick as sweet whey: providing dairy solids for good volume.
“If bakers switch from sweet whey, which can be declared on the ingredient legend as simply ‘whey,’ they must remember to change the declaration to ‘dairy product solids,’” Mr. Gutierrez advised.
A growing trend is to use higher-end whey ingredients in baked goods because they provide functionality and protein enrichment.
“Whey proteins function very similar to egg proteins in many baked goods,” said Gwen Bargetzi, director of marketing, Hilmar Ingredients, Hilmar, CA. “For example, whey proteins can provide volume and contribute to a pleasant appearance in cakes while in cookies, whey proteins function much like eggs in terms of providing color, thickness and chewiness.”
Grace Harris, Hilmar’s manager of applications and business development, added, “In cake applications, WPI can provide aeration properties similar to egg whites. In cookies and muffins, WPC can bind water and form gels, which helps retain moisture, thus contributing to a moister, softer texture.
“Whey proteins can be dry blended with other dry ingredients, hydrated with liquid ingredients or made into a slurry,” she continued. “Each formulation will have its own demands depending on the ingredients, manufacturing operations and process.”
During preparation of whey proteins, their texture attributes can be adjusted selectively. “For example, we’ve modified a whey protein hydrolysate to uniquely address water binding and other activity to provide a softness and pliability that keeps higher-protein bars from becoming nutritional bricks over time,” Ms. Harris explained.
Whey crisps and nuggets represent another way to incorporate whey proteins into baked foods and snacks. “These can be used as nutritional substitutes for cereal-based ingredients,” she observed. “Many consumers prefer bars with texture, finding them easier to consume than typical extruded bars. We call this the ‘crunch factor.’ As they look for healthier snacks and more robust baked goods that are almost mini-meals, consumers will likely shift from standard granola or cereal bars to bars with increased protein content and quality.”
Sometimes dairy proteins are added to a formulation via a traditional dairy food product. This approach adds marketing impact. The baker can flag its inclusion on product labels to create a point of differentiation in the crowded baked goods aisle. “For example, Greek yogurt has shown tremendous growth and consumer popularity over the past five years,” Ms. Gerdes said. “Bakers can add Greek yogurt to a variety of chemically leavened bakery products to boost protein, increase shelf life and achieve a consumer-friendly label.”
Capitalizing on this consumer trend, the US Dairy Export Council developed a high-protein waffle that lists Greek yogurt as its first ingredient. This waffle prototype will be showcased at the Institute of Food Technologists’ 2011 Food Expo in New Orleans, LA.
The powers of protein in baked goods are many, and more continue to come to light as ingredient suppliers develop sophisticated egg and dairy protein ingredients.