Proteins Power Up

Proteins are the essence of life. They are part of every living cell and a major component in enzymes and many hormones responsible for many regulatory and immune functions. Nutritionists have long recognized and promoted the need for adequate protein and the essential amino acids for basic health. However, consumer demand for protein is changing as research defines specific, unique aspects of individual proteins for optimal health, and the appropriate mix of carbohydrate, protein and fat in a diet. Today, consumers are becoming more particular about just what and how much protein they eat.

Ingredient manufacturers now market many specialty proteins for their potential nutritional and health benefits. A steady stream of value-added foods and beverages with an emphasis on protein content are appearing in the marketplace. Products with high protein and branched-chain-amino-acid content meet the needs of sports-nutrition enthusiasts. Soy protein is recognized for its potential to reduce heart disease and also appeals to women wanting to avoid menopause symptoms. High-protein, low-carbohydrate foods appeal to consumers following the Atkins, Zone or similar weight-loss diets. In the future, milk proteins will probably take their place as aids in weight and/or blood-pressure management.

The ability of a protein to supply all the essential amino acids in the required amounts determines its nutritional quality. Over the years, scientists used a number of methods to rate protein quality, such as protein efficiency ratio (PER) and amino-acid scoring. Today, the preferred method is protein digestibility corrected amino acid score (PDCAAS) because it takes into account both the amino-acid content and bioavailability to humans. In general, animal proteins, such as meat, milk and eggs, have a high biological value. Vegetable proteins, however, have a lower value, making protein quality especially important to those choosing a plant-based diet with little or no animal protein.

From an ingredient standpoint, proteins possess many functional properties of importance in processing and final product quality. In general, proteins can impact gelation, viscosity, foaming, film-formation, water control, emulsification and taste. The attributes vary based on innate composition and ingredient form. Protein ingredients may be concentrated to 30% to 80% protein or isolated to 90% protein to provide more functionality and nutritional value, or partially hydrolyzed to create more functional peptides. Options in protein ingredients keep expanding due to improvements and innovations in processing technology. The choice of which ingredient to use depends on desired product characteristics, nutritional value and cost.

In the dairy-protein arena, whey and fractionated-whey ingredients are hot. Although this high-quality protein source was once considered a waste product from cheese manufacture, advances in processing and recognition of potential health benefits of specific components in whey are creating much interest in its use. New extraction and purification methods hold promise for increasing the availability of whey proteins with desirable functional and nutritional attributes.

Whey contains proteins, lactose, minerals and a small amount of fat. The amount of protein varies from 12% in acid and sweet whey, to 34% to 80% in concentrates and 90% in isolates. Whey proteins are soluble over a wide pH and are subject to heat denaturation. Functionally, they possess gelling, water-binding, emulsification, viscosification and adhesion properties. Nutritionally, whey rates a PDCAAS of 1.0 because it meets or exceeds all the essential amino-acid requirements of humans. Additionally, a number of fractions demonstrate bioactivity in vitro and/or in animal studies.

Whey protein’s high solubility and clarity make it a good choice for clear, acidic, fruit-flavored beverages aimed at the sports and nutrition market. Other applications include processed meats and low-fat products, such as salad dressings, soups and sauces. Research at The Ohio State University, Columbus, demonstrated that when added to low-fat processed meats, whey protein concentrate (WPC) binds water through gelation, creating a moister, juicier product; it also is an economical fat replacement. A sensory study showed these products to be generally superior to commercially available low-fat products and equal to full-fat products.

New technology enables whey protein’s use as an edible film or coating and an encapsulating agent. Additionally, researchers at the Western Dairy Center, Logan, UT, are developing an extruded whey protein product composed of 80% WPC and 20% cornstarch. The resulting textured whey protein (TWP) has potential for use as a meat extender, meat analogue and snack food.

“One of the more unique qualities of whey proteins is their range of solubility,” says Kimberlee J. Burrington, dairy ingredients applications center coordinator, Wisconsin Center for Dairy Research, Madison, WI. “They remain soluble at pHs from 2 to 10. Another advantage is their mild flavor as compared to grain and/or bean proteins.” In terms of processing limitations, Burrington says that UHT or retort processing of beverages fortified with whey proteins is a challenge, but no more so than for other protein ingredients like soy. “Depending on the amount of protein added, whey proteins will have a tendency to aggregate or gel,” she notes. “Casein proteins are very heat-stable under these conditions, but not whey proteins. It is necessary to add stabilizers and buffers, control the ionic environment and utilize heat-stable whey protein ingredients. Homogenization also helps.”

Burrington notes that Foremost Farms USA, Baraboo, WI, is introducing two new WPCs. Both products are made by ultrafiltration of sweet whey and contain about 30% protein. One has stronger gelling properties than a typical WPC-34 and will help bind water and prevent moisture loss upon cooking in processed-meat applications. The other, a heat-stable WPC ideally suited for retort and aseptic products, provides good solubility under high heating conditions. In smoothies, meal-replacement and diet drinks, and infant formula, it can enhance nutritional profile and mouthfeel. In retorted soups and sauces, it ensures a smooth, creamy texture.

“Whey ingredients contain high-quality proteins that contain all the essential amino acids the body requires. Whey proteins, individually and cumulatively, have a variety of bioactive properties, which are just beginning to emerge from recent human studies,” Burrington says. “As a general rule, you would use the 80%-protein and higher whey ingredients primarily for protein fortification of foods. She cites beverages and bars as the most popular foods to protein-fortify, “though you will also see high-protein cookies, cereals and the Atkins-diet products.”

Many new whey-ingredient offerings focus on added nutritional value. One is a WPC from Trega Foods, Luxemburg, WI, that has about 60% protein, high levels of immunoglobulin G (5%), conjugated linoleic acid (1%) and phospholipids (0.5%). Besides the potential nutritional benefits from the high-quality protein and other components, the higher phospholipids provide better emulsification. Another ingredient with a nutritional focus is a glycomacropeptide from Davisco, Eden Prairie, MN. It is high in branched-chain amino acids (leucine, isoleucine and valine) and lacks all the aromatic amino acids (phenylalanine, tryptophan and tyrosine). In addition to its suitability in products for individuals with phenylketonuria, it appears to have other immune and hormonal effects that may improve intestinal health and regulate appetite.

A new and different product, Proti-Oats, is an extruded whey ingredient made by Nuvex, Blue Earth, MN. “It is made into an oat form and contains over 50% protein,” Burrington says. “The inclusion can be added to cookies, bars, cereals, muffins, trail mix, or as a topping to add protein.”

A pioneer in whey protein isolate technology, Davisco manufactures a number of purified whey protein ingredients. These include a whey protein isolate that is manufactured using ion-exchange technology. Laurie Davis, applications manager, says it is “ideal for protein fortification of beverages, bars, confections, bakery and cereal products, puddings, extruded snacks and films. BiPRO® is soluble and stable in neutral- and low-pH systems, clear in solution (depending on concentration), and very bland in flavor.” Processing conditions and desired protein content dictate the use level of these whey protein isolates, but in general, up to 10% can be used in ready-to-drink beverages, and 10% to 15% in bar applications. An instantized version is available for use in powdered beverages at levels as high as 95%.

Davisco also manufactures a highly purified source of alphalactalbumin, isolated using unique ion-exchange technology. Applications include infant formula and nutritional products. In addition, according to Davis, the company’s highly purified source of glycomacropeptide is “isolated using unique ion-exchange and membrane technology. Applications include confections, PKU products and satiety products.”

The company offers a line of whey protein isolates with bioactive peptides. One ingredient, BioZate® 1, has been proven to reduce blood pressure in borderline hypertensive subjects. Applications include beverages, bars, bakery products and confections. In these products, 20 grams per serving provides the level found effective at lowering blood pressure in borderline-hypertensive individuals. Davis adds, “BioZate is slightly bitter in flavor.”

Glanbia Nutritionals, Inc., Monroe, WI, has a new partially hydrolyzed whey protein isolate called BarFlex™. Loren Ward, manager of whey research, says this ingredient is “specifically designed for making high-protein nutritional bars that retain softness and chewiness over time. One problem with protein nutritional bars containing whey protein is that they have a short shelf life as a result of bar hardening during the first few weeks of storage. Results from a six-month accelerated shelf life show that BarFlex retains a softer texture compared to a regular whey protein isolate.” He adds that low-carbohydrate and regular nutritional bars with BarFlex could range from 10% to 40% protein. Currently, the company is also working on solving issues related to whey protein stability in heat-treated beverages.

Soy ingredients that add protein to food and beverages include soy flour, isolates and concentrates. Full-fat soy flour contains 40% protein, while defatted soy flour has 52% to 54%. Concentrates and isolates are higher in protein at 65% and 90%, respectively. All three contribute a number of functional properties to food systems — formation and stabilization of emulsions, promotion of fat absorption, viscosity and dough formation. Flour and concentrates can prevent fat absorption and aid in water uptake and retention, while flour and isolates add cohesion and help in shred formation. Additionally, isolates aid in gelation and fiber formation, elasticity, film formation and aeration.

The soy industry continues to refine soy protein ingredients and enhance their functionality and applicability in different food systems. According to Mian Riaz, Ph.D., head, Extrusion Technology Program at the Food Protein Research & Development Center, and faculty member, Texas A&M University, College Station, TX, “Soy flour is not just a flour anymore. It can be purchased in a variety of forms based on its specific characteristics.... Soy flour is also available in textured form for meat applications [and] can also be purchased as partially defatted soy flour for bakery purposes. It all depends on its application.

“Similarly, soy concentrates and isolates can be purchased based on their very specific characteristics and functionality, like solubility, gel strength, viscosity, emulsification, dispersibility and water-binding ability,” Riaz says. “Soy-food companies have developed an agglomerated product that combines isolated soy protein, soluble fiber and lecithin. The fiber helps mask off-flavor from soy by forming a complex with the protein that prevents the tongue from detecting off-notes, while the lecithin aids dispersion in soy beverages.”

Riaz says that the choice of ingredient and use level depends on the desired properties and characteristics of the food system and the purpose for using the ingredient. A health claim, of course, would require enough ingredient to provide 6.25 grams of soy protein per serving. He adds, “For other purposes, different ranges can be used. For example, enzyme-active soy flour can be used at 0.3% as flour whitener, whereas defatted soy flour can be added at 3% to 4% in breads and other bakery items to improve the protein quality and to get some other benefits. Agglomeration makes soy protein highly soluble and can be used at 10 to 20 grams per serving in both powdered and ready-to-drink soy beverages.”

These specialized soy protein ingredients provide specific functions not available from other protein ingredients. “For example, if we use soy isolates, which have good water-holding properties in emulsified meat, then the advantage is that it will hold the extra water, make a firm gel and result in patties which are juicy and succulent,” Riaz says. “This will have a positive effect on yield and cost, which is the goal of the meat processor. If the processor cannot make a firm gel, then the quality of the meat product will be inferior and give dry mouthfeel — and they will not be able to sell at a good price. More water will come out from the meat products during handling and packaging.” He adds that these ingredients are application-specific and limited only by price and availability.

A recent addition to the soy-product line of Archer Daniels Midland Co., Decatur, IL, is a soy-protein/fiber/ lecithin ingredient for beverages that has excellent water dispersion and a clean taste. The company also produces and markets a retail product for the consumer and foodservice markets, Soy7™ Pasta, which provides 7 grams of soy protein per serving, thereby qualifying for a heart health claim.

“Our newest and most unique product is NutriSoy™ whole-bean powder, which is the whole bean ground and spray-dried, intended for use primarily as soymilk and in dairy analogueues,” says Russ Egbert, director, protein research and applications. He adds that it is easily incorporated into dairy products, requiring no new equipment, and allows dairies to produce soymilk. It contains about 40% protein, and when reconstituted as soymilk, provides about 7 grams per serving with a fat content similar to reduced-fat milk.

“This product addresses the issue of whole foods,” Egbert continues. “Its advantages are that it keeps the fiber and other healthful components, like isoflavones and phytosterols, and eliminates the waste product normally produced when making soymilk. Its one disadvantage is that you can’t get a low-fat claim.” He adds that the company is addressing the need for a low-fat version of whole-bean powder.

According to Egbert, high-protein rice crisps are a growing area. He says, “We produce specially isolated soy protein with specific viscosity profiles that are being used to meet the needs of different twin-screw extruders in a specialized market for high-protein rice crisps. These ingredients are intended for use in the nutritional-bar market that can range in protein from 30% to 80%, but most are about 70% to 80%.” He also states that a new generation of meat analogues aimed at the foodservice market will become available in the near future.

“Many of our innovations have allowed our soy proteins to provide exceptional flavor and functional performance in a wide range of products. These include product improvements specially designed for beverage applications,” Jim Holbrook, vice president, food science research and development, The Solae Company, St. Louis, says. “For example, soy proteins can now be added to acidic beverages (citrus- and other fruit-based drinks) and remain in solution. Our ALPHA proteins, based on a revolutionary new manufacturing process, provide improved flavor and exceptional functionality, especially in dairy-alternative products — including great-tasting beverages and cream cheeses. For nutrition bars, our extruded soy nuggets deliver enhanced textural properties — adding crunch — and have the potential to positively affect shelf life.”

“We also offer soy proteins with guaranteed levels of isoflavones, important health-promoting components found in soy,” Holbrook adds. “Our soy proteins are supported by over 30 years of research proving their quality and health benefits.” He says the company also co-processes soy protein with other ingredients to enhance nutritional and functional attributes. The soy protein ingredients can be incorporated into in a variety of foods including meat and poultry products, meat alternatives, beverages, food bars, cereals, frozen entrées, non-dairy frozen desserts, soymilk, soups, baked goods, infant formulas and enteral feeding products. “Inclusion levels can vary from a few grams per serving, to the levels required to use the soy-protein heart health claim (6.25 gram/RACC), to larger amounts of 15 grams plus for performance nutrition bars and beverages — it all depends on the application and positioning,” he says.

Gluten, the protein in wheat, is responsible for the structure of many baked products. It is composed of two fractions — gliadin and glutenin. Wheat gluten has long been used as a functional protein for its elastic and cohesive properties, important to the texture of many bakery products. Unlike whey and soy proteins, wheat proteins are not high in biological value and have not been widely researched for nutritional advantages. However, they do possess functional attributes that enhance product quality in foods beyond baked goods.

Textured wheat protein is unflavored, dry wheat protein that is available in powder and flakes and chunks of various sizes. According to Brad Maier, director of protein products, MGP Ingredients, Inc., Atchison, KS, it improves the texture and flavor profile when used in meat analogues and mimics the fibrous profile and mouthfeel of meat when used as a meat extender in shredded and ground meat. In fact, vegetarian chicken-style and extended poultry nuggets made with textured wheat protein rated higher in taste, texture, mouthfeel, firmness and aftertaste when compared to poultry nuggets made with textured soy concentrate and flour.

Wheat gluten is a concentrate of wheat protein produced by removing starch from flour. Its functional properties include dough strengthening, gas retention and controlled expansion that produces uniformly shaped products; improved water absorption and retention; and added natural flavor and color. It has wide application in bakery products and other foods.

Wheat gliadin, a protein fraction of gluten with very low ionic strength, has a delicate balance of hydrophilicity and hydrophobicity, and excellent film-forming capabilities. Although insoluble in water, a surfactant or pH adjustment will result in its dissolution. It helps improve dough rheology and product quality in bakery applications such as mixes, fresh baked goods, and frozen and refrigerated doughs. Wheat glutenin, the other fraction of gluten, has highly elastic and rubbery properties, has resistance to shear in dough systems, and helps strengthen frozen and refrigerated dough. It is insoluble in alcohol and neutral water, requiring the addition of a surfactant or a pH adjustment to dissolve.

At MGP Ingredients, the development of new products and applications for ingredients is the result of ongoing technical research on the natural functional aspects and benefits of wheat protein, coupled with close monitoring of consumer needs, according to Steve Pickman, vice president, corporate communications and marketing services. “For example,” he says, “new applications for our ingredients include high-protein, low-carbohydrate bread applications and improved tortilla-flour softness and pliability.”

Maier also points to a line extension of wheat protein isolates as the result of customer-driven research to meet consumer needs. This line aimed at improving dough performance in bakery products was launched about two years ago. Maier explains, “Arise 5000™ has more low-molecular-weight protein, gliadin, [and therefore] has more film-forming capabilities that translate into more volume, reduced mix time and less toughness. For example, in a pizza crust, it reduces the mix time and relaxes the dough.” Other benefits include extended shelf life, fresher taste, better mouthfeel and improved color, crust and texture. He adds that one version of these isolates is designed to replace egg and egg whites in pasta, resulting in lower costs. Functionally, it increases firmness and reduces stickiness, and binds flavors and seasoning.

Another new product is a lightly hydrolyzed, water-soluble wheat protein developed specifically for the beverage and nutrition-bar industries. It delivers peptide-bonded glutamine and contains 80% protein, with 30% of it as glutamine. “It is mostly used for nutritional purposes but is a non-functional protein, which ends up reducing hardness over time because it doesn’t compete for water,” Maier says. However, in the nutritional-foods market, dairy and soy are predominant and the inclusion of a wheat gluten may add another known allergen to the formulation.

Long a staple in the food developer’s ingredient kit, eggs offer functionality and high nutritional value. Much of the functional attributes that make eggs a desirable ingredient come from the proteins found in egg white and yolk. Egg whites are an excellent foaming agent due to the proteins that when whipped, stabilize small air globules to create a large volume. Heating then coagulates the protein to form a stable foam structure. A combination of some proteins and phospholipids present in the yolk are key to the emulsification properties of egg yolks. Last, heat coagulates egg proteins, which binds other ingredients and gives structure to foods.

A variety of egg products are available for use in food manufacture. Refrigerated liquid eggs can be whites and/or yolks. Frozen egg products usually contain salt, sugar or corn syrup to control gelation and viscosity during freezing. Dried egg products come in many forms — spray-dried, instantized, stabilized (glucose-free), and with flow agents and added carbohydrates. While most of these are not recent inventions, their increasing use in today’s products might be considered as such. Joanne Ivy, senior vice president, American Egg Board, Park Ridge, IL, predicts “manufacturers may be returning to eggs now that the taboos on eggs have been lifted by the American Heart Association.” She adds that there may be more use of shell eggs to meet consumer demand for high-protein foods and a natural label.

The world of functional proteins is expanding to include other vegetable-based proteins. Burcon NutraScience Corporation, Vancouver, British Columbia, has developed a patented process that uses an ionic shift rather than a pH shift to extract the canola protein from canola meal. The process employs only salt and tap water to create large protein spheres, called micelles, which precipitate. The resulting viscous solution can be used as is or spray-dried. While canola protein is high-quality in terms of its amino-acid content, anti-nutritional factors in the canola meal prevent its use for human consumption, and standard processing used to extract proteins is not commercially viable for canola.

Functional properties of canola protein isolates include solubility in neutral and acidic conditions, emulsification capacity, whipping and foaming properties, viscosity and gelation. Potential uses include protein ingredient or supplement in high-protein products, egg replacement or extender, dairy- or soy protein replacement in products for those allergic to dairy and soy, animal protein replacement and personal-care-product ingredient. Research on safety and plans for commercialization are now underway.

The variety of available protein ingredients offers many opportunities for enhanced functionality and nutrition in existing and new products. Diversity in protein choices for consumers is essential for many reasons — taste, potential health benefits, and allergenicity concerns.

Angela M. Miraglio, M.S., is a registered dietitian and Fellow of the American Dietetic Association from Des Plaines, IL. She has extensive experience in trade communications, public and consumer affairs and technical communications, as well as product development and nutritional assessment. Her firm, AMM Food & Nutrition Consulting, provides food and nutrition communications and technical-support services to food and beverage companies, and trade and professional associations. She can be reached via e-mail at [email protected].

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