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Boosting Protein ContentBoosting Protein Content

April 25, 2008

18 Min Read
Boosting Protein Content

Of the major food components—carbohydrates, fat and protein—only protein has an unblemished reputation. Carbohydrates and fats have been maligned by diet faddists, but it seems no one can find fault with protein.

Indeed, it is the basis of all bodily needs, from hair development to muscle mass. It’s critical to life and, within the body, it’s second only to water in abundance.

A food developer often thinks about protein in terms of the ingredient declaration or the nutritional panel, but that’s the smallest part of the story. Protein is multifunctional. Choosing the right protein for a particular application requires an understanding of all the ways a product might be impacted, from labeling to shelf life.

Soy options

Linda Beck, global product/process development manager for soy, Cargill, Minneapolis, notes that soy protein is typically added to beverages and bars for protein fortification. “Even though you’re adding it for protein, you have to be very aware of the functionality,” she says. “All proteins are going to affect functionality. Depending on what textural and manufacturing parameters you have to meet, that’s going to dictate what protein you’re going to need.”

Soy is making an entrance into beverages that were once classically dairy drinks. In general, a beverage containing soy protein is going to be more viscous than a comparable dairy product. “Soy protein is not going to have as high a solubility as dairy proteins,” Beck says.

Soy flavor, even if mild, is a consideration when formulating for a dairy market. “In North America and Canada, we are a dairy-based culture,” Beck cautions. “This is not the case when you go to Asia and other parts of the world, or if you’re servicing different ethnic populations within the United States.”

In making beverages, use of an isolate vs. other soy ingredients is more typical because of the higher protein content. When choosing a protein ingredient, “the formulator also has to be aware of how much room you have in the formula,” says Beck. Isolates have 90% protein, concentrates are around 65% to 70%, and flours are in the 50% range. “So, if you’re delivering a targeted protein amount, say 10 grams of protein in 8 oz., you’re going to have to use a lot more concentrate or flour,” she says. “That’s going to have an effect on your formula—and, based on the other ingredients in there, do you physically have room? That alone can dictate your choice.”

Cost is another important consideration. “If you’re delivering protein, it’s not the cost per pound of the ingredient,” explains Beck. “It’s the cost per pound of your protein. With today’s escalating prices of dairy, formulators should start looking at combining protein.” She recommends adding soy protein isolate to a dairy-based beverage to reduce cost. If labeling allows, the key is finding the level of soy that will not affect flavor, but will cut costs.

Soy protein isolates and soy protein concentrates are typically used in North America. “That’s not true of everywhere,” says Beck. “For example, our European division makes full-fat soy flour that is used in beverages.”

Soymilks can be made from different processes. In one case, manufacturers grind the bean and remove the insoluble materials from the soluble materials. The soluble material is composed of the protein, the soluble sugars and fat. That product is shipped to soymilk processors who then add flavor.

In the second type of soymilk production, manufacturers crush the soybeans, then remove the oil, so only the protein, the soluble carbohydrates and the insoluble carbohydrates remain. Depending on how it’s ground and treated, “you could have soybean meal for animals, you could have soy flour or textured soy flour,” says Beck. “There is more than one type of soy flour. You can remove the soluble carbohydrates, and now you have a concentrate. Remove all the carbohydrates, now you have an isolate.” Some companies might buy soy isolate, buy a vegetable oil and buy a sugar source, but that’s not necessary. “Put all the parts back together, and they, too, are soymilk,” she explains. “In Europe, there are several companies that make full-fat soy flour. You’ve got the fat, you’ve got the protein and you still have all the carbohydrates. You have a nice powder to work with instead of shipping liquids all over. Soy flour is used in beverages—we just don’t see it much in the United States.”

In cereals and bars, textured soy flour could provide crunch and texture, similar to an oat, but it would contain more protein. Beck suggests using regular soy flour to boost protein in cereal flakes. “And, using soy flour would be a more-economical choice than a concentrate or an isolate,” she says. “Soy flour contains protein and insoluble carbohydrates, i.e., dietary fiber, and it’s still less than 1% fat.”

According to Beck, more cereal and bar companies should consider incorporating soy flour, which will allow them to “back off on some of their cereal grains. They’re going to get more protein and have a label that’s going to read better for the consumer,” as well as provide a better balance between protein, carbohydrates and fats.

Historically, soy flour has served as an egg replacer in cookies and muffins. Because it can repulse fat, in the doughnut industry it helps prevent fat absorption during the frying process.

When using soy, it’s important to remember that, in general, some soy proteins tend to bind more water than other proteins. Some soy proteins do not. Beck encourages formulators to talk with their soy supplier and discuss their parameters. “Soy products are manufactured with different viscosities and different end products in mind,” she says. “The more the formulator is willing to share with the soy manufacturer, the better they can target which soy product to send.”

Rice possibilities

“In recent years, rice proteins have become more and more popular in food and beverage applications worldwide,” says Gil Bakal, managing director, A&B Ingredients, Fairfield, NJ. One reason for their popularity is they are hypoallergenic.

Nutritional-grade rice protein has a minimum of 70% protein. “You can use rice proteins in high-protein breakfast cereals, cereal bars, meat coatings, rice and pasta applications,” says Bakal. In gluten-free pasta and bakery applications, and in cereal and energy bars, rice protein can increase nutritional values. “In meat coatings, rice protein can enhance the crunchiness after frying,” he continues. “In batters, we know that 2% enhances the crunchiness.”

Another rice-protein application is in breakfast cereals, where it can increase bowl life by reducing sogginess. “This phenomenon is visible with a dosage of 10%, and you can go up to 30% without noticeably changing taste and expansion,” Bakal says.

Depending on the application, rice protein can be added at 2% to 60% of the formula. Generally, in nutritional cereal bars, breads and cookies, a formula may contain up to 10% rice protein. “In the United Kingdom, we have a customer making protein breakfast cereals using up to 60%,” says Bakal. Rice protein has a slight rice flavor, but no bitterness. The disadvantages are that it is not soluble, and rice supplies are tight, potentially limiting future availability, he says.

Investigating pea protein

Pea proteins range from 85% to 90% protein on a dry-weight basis. According to Carl Jaundoo, Ph.D., associate program coordinator, Roquette America, Inc., Keokuk, IA: “Pea proteins are high-quality proteins with digestibility comparable to the best animal proteins. Pea proteins also have an excellent amino-acid balance and low allergenicity, and are not listed on the U.S. and EU major allergen lists.”

Pea proteins can work well in applications where soy proteins are currently used, such as beverages, snacks, sauces, dressings, pasta, cereals, baked goods and nutrition bars. “Pea proteins can be used at varying levels up to about 75%, depending upon the application,” Jaundoo says. “In extruded snacks, pea proteins have been used to provide a snack with 65% protein. In other applications, such as beverages and bakery snacks, the desired finished protein content determines the use level of protein incorporated. In sweet snacks such as cookies, pea proteins can be added at about 3%.”

In vegetarian foods, pea protein provides an alternative to soy. According to Bakal: “In formulation, pea protein varies between 6% in weight-control shakes to 14% in sport-nutritional shakes. Within protein bars, levels can be up to 17%.”

Pea protein has a slight vegetable taste, but a minimal impact on the final flavor. Depending on the application and the product used, the effect on texture is low to medium. Unit cost-related factors are similar to that of rice protein.

Jaundoo notes that the solubility, viscosity, fat and water-binding capacity of pea protein are comparable to other vegetable proteins. “There is a range of commercial pea protein products available that provide varying physical and functional properties,” he says.

Working with wheat protein

Wheat protein works well in a wide range of products, especially in applications with flour as the primary source of protein. “Wheat protein complements other proteins,” says Steve Ham, director of marketing, specialty ingredients, MGP Ingredients, Atchison, KS. “In certain cases, this combination can help create a more-balanced amino-acid profile, as well as provide diverse functional properties. Consumers, as well as manufacturers, are recognizing the nutritional benefits of elevated protein levels.”

While wheat gluten, with 75% protein, is generally considered a cost-effective ingredient, Ham notes that, in some formulations, it can affect dough handling. “Our wheat-protein isolates are beneficial when formulations require high levels of protein,” he says. “Because of their extensible nature, these isolates allow for greater consistency in dough handling and finished product qualities.”

Topher Dohl, applications technologist, MGP Ingredients, adds: “Vital wheat gluten has unique viscoelastic characteristics. Adding wheat protein isolates to a mix or formulation increases dough extensibility and can increase dough-processing efficiencies.”

MGP Ingredients offers three different wheat protein isolates with 90% protein and varying levels of extensibility and elasticity that fit functional needs of various applications. Dohl cites tortilla dough as an example of applications where extensibility is highly important. “Our protein isolates also provide benefits in laminated dough applications or pressed products like pizza crust or a flatbread. In whole-grain bread, these isolates perform as strengthening agents to effectively suspend particulates. The types of ingredients that are found in whole-grain products tend to weaken dough significantly. As a result, additional strength is required to help suspend these ingredients and improve processing tolerance.”

Typical usage levels of wheat protein isolates range from 1% to 3%, based on the type of flour used and desired end results.

In many products, balancing the amino-acid profile is important. “Wheat protein is high in glutamine, roughly 30%,” Ham says. “There are numerous studies that highlight the benefits of glutamine for helping the body recover after exercise.”

Because of their binding properties, wheat protein isolates can partially replace egg whites. They can add textural firmness to pasta, for instance. This is especially beneficial in products subjected to stress, such as retorted or frozen pasta, or in steam-table foodservice applications.

When fiber, such as resistant starch, replaces a portion of a product’s flour, protein is often added back to the formulation.

Protein-packed eggs

When it comes to delivering a powerful dose of protein, eggs present a number of possibilities for product designers.

Over half of the protein found in whole eggs comes from the white, or albumin. According to the American Egg Board, Park Ridge, IL, egg whites are about 88% water and 10% protein. When dried to create various egg ingredients, egg white can become a concentrated source of high-quality protein. Egg albumin has a protein digestibility corrected amino acid score (PDCAAS) of 1.18, which is above and beyond the 1.0 score for proteins that meet all essential-amino-acid requirements.

A range of processed egg products make it easy to incorporate this high-quality protein in many applications, including grab-and-go breakfast products and classic quiches. Whole eggs, egg whites and egg yolks are available in frozen, refrigerated liquid and dried forms. Specialty products, such as pre-peeled hard-cooked eggs, egg patties, quiche mixes and scrambled eggs, offer cost savings and convenience.

Whey potential

Whey products are available at a variety of protein levels. Whey powder is around 12% protein. Whey protein concentrate (WPC) can contain 34% to 80% protein. Whey protein isolates (WPI) typically have 90% protein. “In general, whey proteins are very bland in flavor, with blandness increasing as the whey’s protein content increases. WPI is more bland than whey powder,” says Grace Harris, manager of applications and new business, Hilmar Ingredients, Hilmar, CA. “As the protein level increases, the functionality of the whey protein also increases. Suppliers can then do further modifications to the proteins for specific nutritional contributions and advanced functional benefits, such as heat stability, acid stability, gelation and emulsification.”

According to Eric Bastian, director of R&D, Glanbia Nutritionals, Monroe, WI, many health benefits are associated with whey protein. Whey protein’s unique branched-chain amino acids “push the human body into a higher protein synthetic state than when you’re taking protein with lower levels of branched-chain,” he says. This is why whey protein has been effective for bodybuilders working to increase muscle mass.

Some of the minor protein fractions in whey, namely alpha-lactalbumin and lactoferrin, have been shown to play a role in immune response. “Additionally, we’ve done quite a bit of work on whey proteins and peptides in weight management,” he says. “We’ve got good clinical scientific data showing that these proteins, when they are taken in conjunction with reduced caloric cycles, people can actually reduce their body fat and preserve their muscle mass during a weight loss period. It’s related back to the original use with bodybuilders.”

As science has become more interested in validating “food as medicine,” a new focus on “mining” the unique health components of whey protein has arisen, suggests Gwen Bargetzi, director of marketing, Hilmar Ingredients. “For example, we have a new ingredient, an alpha-lactalbumin-enriched whey protein concentrate, designed to help manufacturers take advantage of alpha-lactalbumin’s health benefits, such as mood support, mineral absorption and regulation of gut microflora, along with the expected functional benefits of whey protein,” she says.

Historically, advances in whey protein ingredients have been in maximizing functionalities such as gelation and improved dispersibility. “Hilmar, in particular, has done some pioneering work in large-scale, continuous agglomeration to provide whey proteins with critical consistency in dispersibility and flavor,” says Bargetzi.

Whey proteins can contribute viscosity in shake-type ready-to-drink (RTD) beverages and puddings; low viscosity and excellent clarity in high-protein RTD acidic beverages; moisture retention and shelf-life extension in food bars; color and flavor attributes via the Maillard reaction in bakery; and structure and syneresis control in yogurts and dairy applications.

From a functional standpoint, there is really no reason to consider soy, because Bastian finds adding whey protein to beverages can assist with suspension of small particulates. “We’ve been able to show that you can reduce a stabilizer with whey protein in the system, so it gives you some stability benefits,” he says. “Usage will depend on what you’re trying to suspend in the system. I’m thinking about a particular beverage where we were trying to suspend some ground flax meal for added omega-3s. We were making an RTD with flax, and we found that when we have a little bit of whey protein in there, we can reduce the stabilizer in the system by maybe 20% or 30%. You wouldn’t do that purely for stabilization impact, because stabilizers are cheaper than whey protein, but if you are looking to have the nutrition of a protein in the system, it can add texturizing and stabilizing effects at the same time.”

Improved mouthfeel may result from added whey protein in such a system. Bastian notes that when a stabilizer was incorporated at a high enough concentration to disperse the ground flax, the beverage was too thick. “It almost became slimy,” he says. “When we dropped the stabilizer back again without the whey in there, we thought the particles weren’t suspended as well as they should be. But, by doing a combination of whey and stabilizer, we were actually able to get a fairly nice mouthfeel in that beverage.”

Partially hydrolyzed whey proteins can increase shelf life of bars. “Intact proteins in these bars tend to harden over time,” says Bastian. “By manipulating that protein system, you can create softer bars. Shorter peptides have some effect. In lower-protein bars, you can probably do the job with your standard humectant glycerin and your selection of your sweetener, and you can probably maintain some softness.” But increasing that level of protein presents a harder challenge. “As you increase the protein in a bar, the hardness issues are going to be exacerbated,” he continues. “You need to make sure that you select the appropriate proteins so that you can maintain softness.”

An off-the-shelf WPC80 or WPI will not necessarily maintain softness across the shelf life. “We’ve spent a lot of time working on developing protein products for bars,” says Bastian. “Even if you buy a standard WPC80, which is a commodity, it’s variable from manufacturer to manufacturer. When you’re talking about a more-specialized product, like what you would want to put into a protein bar, absolutely there are major differences in product from manufacturer to manufacturer, and even within one manufacturer there are differences.

“We offer about four different types of protein systems for bars, and each one of them has its own niche area and unique benefit,” Bastian continues. “When we talk to our bar customers, we first of all have to try to find out what kind of bar are they making. What’s the protein level? What’s the coating? Are they putting any kind of nuts or chocolate on the bar? All of these things have a bearing on what you’re going to select to put into it.”

Harris says food bars rely on several facets of whey protein, from texture and shelf-life improvements to nutritional quality. “One of our basic bar formulations can be tuned to deliver up to 30% protein,” she says. “This formula uses whey in a combination with different milk proteins, and even soy proteins in some cases. We do that because we know each protein can contribute different advantages, and because orchestrating the proteins achieves a specific profile to suit each customer’s objective for their bar.”

Selection of a protein for a beverage depends on its pH stability and its sensitivity to heat. “Solubility of whey proteins is excellent across the pH range, unlike other milk proteins that contain casein,” Harris says. “These will precipitate at pHs approaching 4.6 (isoelectric point). The isoelectric point for whey protein is typically between 3.5 to 5.2. This upper end is where you may see some destabilization of the protein.”

The isoelectric point is the pH point where the charge on the protein is neutral. “As we go below that isoelectric point, they become positively charged and they start to repel each other,” says Bastian. “We found that around pH 3, they are strongly, positively charged. Even though you heat them, they still denature or unfold, but they don’t aggregate at that pH. So the two major areas where whey proteins have been used in beverages is, first, in the acidic range, pH 3, and then in the neutral pH range, pH 7. The more-difficult pH range is the one around the isoelectric point. The whey proteins are pretty soluble at their isoelectric point as long as you don’t apply heat to them, but when you start applying heat, they start to precipitate. Then that causes issues to try to make a beverage that’s, say, at pH 4 or pH 5. We don’t have a lot of examples of whey protein beverages in that mid-pH range. It’s a difficult range to work in.”

Clear protein waters are generally low-pH. “They call it water, but it’s actually an acidified water with a little bit of protein put into it—and of course they flavor it,” says Bastian. A typical formulation level is 1.0% to 1.5% WPI. “But, again, there is a wide range of protein inclusion into beverages. You go to more of a sports-nutrition, and we’ve seen as high as 45 grams of protein being delivered in one of the bodybuilding RTD beverages. Of course, that’s in the acidic range, and you have to push the pH even a little bit lower to get that high protein level in there and have it stable.”

Whey protein manufacturers have some tricks up their sleeves to increase heat stability. “Whey proteins, just as they come off the cheese, inherently are fairly sensitive to heat,” says Bastian. Controlling minerals and levels of hydrolysis are just a couple of the techniques in a protein manufacturer’s tool kit.

According to Harris, one word describes the trick to protein selection—discussion. “Always have an as-open-as-possible discussion with your supplier about what you want the protein ingredient to do, how you plan to process it, and what type of a nutritional profile you are trying to achieve,” she advises. “A good supplier—one who knows their protein ingredients’ composition and behavior—will give you the best recommendation for your application. Look for experienced technical support, resources and responsiveness. These three attributes will enable you to develop your product quickly and successfully.”

Cindy Hazen, a 20-year veteran of the food industry, is a freelance writer based in Memphis, TN. She can be reached at[email protected].

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