Gluten present in flour plays a vital role in baking; however, there is a lot more to proteins in baking than just the functionality of gluten. Proteins can be added to a formulation for a variety of reasons.
Proteins offer several functional properties in bakery formulations, including emulsification, water binding, aeration and solubility, according to Carl Jaundoo, associate program coordinator, food applications, Roquette America, Inc., Geneva, IL, Mr. Jaundoo stated that because proteins have excellent solubility over a wide pH range, except at or near their isoelectric point, incorporation of proteins in bakery applications can be easily accomplished. (The isoelectric point, or pI, is the pH at which a particular molecule carries no net electrical charge. This value can affect the solubility of a protein, and at the pI, proteins tend to precipitate out of solution.)
In several bakery products, where a light or airy texture is desired, proteins provide the structure to entrap air and leavening gases and contribute to texture. In bakery products, water activity and its effect on shelf life are also important considerations. Proteins have good water-binding capacity and can be used to control the texture and shelf life.
The choice of protein, use level and process/formulation adjustments is determined by functionality and the finished product characteristics. For example, with water binding, proteins will compete for the available water. Thus, the formulator may have to increase the amount of water or add the proteins at a later processing stage. In addition to the specific functionality and possible label claims, the choice may be only driven by costs. Mark Baczynski, technical manager, Manildra Group, Fairway, KS, concurred that the selection of proteins depends on the application. The addition of wheat proteins is usually not a challenge; however, other proteins such as soy and dairy can make doughs soft and diffi cult to handle. If the aim is to make a high-protein bakery product with limited sensory sacrifice, then the best way to formulate is to use a combination of protein ingredients, and there are many to choose from.
THE OTHER SIDE OF WHEAT. Mr. Baczynski stated that wheat proteins can be modified to contribute to the development of viscosity, whipping, foaming, film formation, adhesion, water control and emulsification with minimal negative impact on flavor. The attributes of wheat proteins vary based on inherent composition and ingredient form. The amino acid profile of wheat provides a synergistic effect when used in combination with other protein sources such as soy. Vital wheat gluten is the most common choice when adding protein in the form of gluten, and its advantages include increased oven spring, ability to support a large amount of whole grains, dough stability during baking and increased water absorption. Modified wheat proteins can partially replace eggs in cake and muffin applications and have been used to help reduce mixing time of high-gluten whole-grain formulas.
Mr. Jaundoo also noted that vital wheat gluten facilitates the structure development in breads made with different proteins. Using vital wheat gluten allows bakeries to combine flours with varying protein content without changes in the manufacturing process or the finished product.
Another protein available for bakeries is hydrolyzed vital wheat gluten. This product offers the same protein content as vital wheat gluten but with limited functionality such as elasticity and extensibility. Mr. Baczynski explained that a balanced combination of vital wheat gluten and modified gluten proteins tends to give processing ease and a good sensory profile and is cost effective.
SOY-BASED CHOICES. Soy protein added to bakery formulations decreases staling by holding more water during baking, thus decreasing the bake loss, stated Mian Riaz, PhD, director of the Food Protein R&D Center, Texas A&M University, College Station, TX. Enzymeactive soy flour (50% protein) can be used in place of other conditioners as a crumb whitener.
In general, soy protein provides excellent waterholding capacity during baking, according to Dr. Riaz. One kg of soy flour can hold 1.5 kg of water. This will result in two or three extra loaves from each batch. He noted that the addition of soy protein requires little adjustment in a bakery processing operation, and by adding protein to snacks, the soy will improve their nutritional value. Soy proteins come in different forms including soy concentrate (65% protein) and soy isolates (90% protein). By choosing the right source of soy, nutrition bar manufacturers can increase the protein content of a bar without changing anything else in the formulation.
A PEA IN A BUN. Minimally processed or natural sources of proteins represent areas of increasing interest among food processors, according to Mr. Jaundoo.
The recent introduction of pea proteins, derived from yellow peas, is an example of proteins that meet the definition of a natural protein source. Golden pea protein is an ingredient that contains 83 to 85% protein and has been developed for the fortification of foods. A pea protein ingredient has been designed as an egg replacer in bakery products. Bland pea flour is ideal for “bleaching” all-white breads (actually, an enzymatic process that whitens the yellow pigments naturally present in flour) and works synergistically with ascorbic acid to replace bromate.
Pea protein not only can enhance the protein content of foods without changing the texture but also provide a low flavor profile that permits increasing of protein levels without changing the flavor of high-fiber, high-protein, low-calorie breads. In bread applications, the starch content can be reduced by a combination of pea protein and dietary fiber to increase satiety. Sensory evaluation showed no difference in taste and texture between the control and the bread using protein and fiber as replacers for some of the flour. In addition, pea proteins are among the most economical and widely available sources of proteins; thus, they present a good alternative for cost reduction.
RAISING THE BAR. Many nutrition bars are rich in carbohydrates. The challenge, explained Mr. Baczynski, has been to add higher levels of protein to bars that combine identity preservation, nonanimal sources, cost effectiveness, extended shelf life, improved sensory properties, efficient processing and versatility. In addition, many high-protein bar formulators encounter the common problem of product hardening, which negatively affects palatability. Moisture migrates within the product over time, and the protein quickly absorbs that moisture, thus hardening the bar undesirably. To solve this problem, many bar manufacturers use glycerin as a plasticizer.
Partially hydrolyzed wheat proteins with shorter peptides have less water-binding potential compared with isolates and their longer protein chains. The shorter-chain wheat proteins can be used to control water migration and reduce drying and hardening. Furthermore, smaller peptides are absorbed faster by the body, which is highly desirable in sports nutrition for recovery after exercise.
The hydrolysate also contains more than 30% glutamine, whereas in most proteins, the glutamine content is approximately 3 to 7%. Glutamine enrichment is associated with recovery from physical stress after strenuous exercise or other events. For reduced-calorie bar applications, wheat protein hydrolysates and isolates can provide body in the product and enough elasticity to ensure easy processing. In addition, proteins such as wheat gluten can give structural stability to snack products that are extruded into novel shapes.
Whey proteins also can be used to obtain different texture profiles. For example, whey protein concentrate and whey protein isolate can add “shortness” and chewiness to a bar, and a whey protein hydrolysate provides softness. A combination of different whey proteins can aid in water binding and flavor improvement. Also, whey protein crisps can be used to address different color and texture needs. High-protein crisps allow bar manufacturers to avoid the problems of solubilizing highly viscous high-protein ingredients while still providing a high protein content profile.
THE FREE-FROM MARKET. Several vegetable protein ingredients can be used as “alternative” or “replacement” proteins, according to Jon Stratford, sales and marketing manager, Natural Products, Inc., Grinnell, IA. For example, ingredients derived from soybeans share functional properties with animal proteins, namely eggs and dairy (nonfat milk powder). The use of vegetable proteins can provide functionality and do what is normally done by animal proteins. This is quite attractive for companies searching for either cost reduction or serving niche markets such as “egg free,” “dairy free,” “cholesterol free” and so forth. The hottest trend in this area is clearly “gluten free.” However, lactose- or milk-free and egg-free are steadily growing categories as well.
Another hot new area may be to use different proteins to achieve “gluten-free egg replacement.” As Mr. Stratford explained, the key benefits of using vegetable proteins vs. animal proteins are cost reduction and pricing stability. However, certain attributes such as shelf life and eating qualities can be improved by using the right vegetable proteins. A whole-egg replacer takes advantage of the functionality of soy protein and wheat protein to extend or replace eggs in batters and sweet doughs. This type of blended protein system duplicates the emulsification, water-binding and structure-building properties of whole eggs. The functionality comes largely from the water-loving nature of soy protein and structure-building property of wheat protein. The key nutritional advantage of this type of system would be the potential for cholesterol reduction.
Another vegetable protein blend can be used as a milk replacer. In this case, the emulsification and water-binding properties of soy protein allow manufacturers to eliminate milk from the label and stabilize costs.
DIETARY CONCERNS. Recent ingredient introductions present more options when formulating for the “metabolically challenged.”
For example, Arla Food Ingredients, Basking Ridge, NJ, reported the development of a milk protein suitable for use in foods for people suffering from the genetic disorder phenylketonuria (PKU). Such individuals lack an enzyme that works to break down the amino acid phenylalanine, which is found in foods that contain proteins. PKU sufferers must follow a special diet to minimize the buildup of by-products that leads to neurological problems and brain damage. To sidestep this dietary requirement, the company developed a milk protein free from phenylalanine that can replace conventional milk ingredients in products such as protein bars.
Adding this protein means that people diagnosed with PKU can avoid undesirable supplements and eat dairy foods without worrying about the consequences. Instead of consuming special amino acids that have an unpleasant taste, they can now enjoy foods where normal proteins have been replaced by the milk protein CGMP (CaseinoGlycoMacroPeptide). It has been found that this protein is suffi ciently pure and can replace protein in foods without adding phenylalanine. CGMP is part of the whey from cheese production and is similar to all other proteins except for the fact that it does not contain phenylalanine.
Regardless of the particular goal of a baker — replacement, improvement, embellishment, simple functionality or cost reduction — proteins can show more than one face and help on all fronts. It is just a matter of finding the right combination for each individual application.