21st Century Functional Beverage Formulation

The penchant for packing nutrition into fluids is a decidedly 21st century phenomenon—consumers are no longer satisfied with a little vitamin C in their soda, or calcium-fortified orange juice.

“Consumers today are looking for beverages fortified with ingredients that are meaningful to health and can offer nutritional solutions for brain health, heart health, immunity, and other major concerns,” says Bruce E. Artman, director, applications development, Martek Biosciences Corporation, Columbia, MD.

Market competition has led to products aligned with consumers’ nutrition awareness. “It’s a point of differentiation,” says Walter Postelwait, vice president, BI Nutraceuticals, Long Beach, CA. “The market has matured over the last 15 years, and everyone’s looking for that new way to promote themselves.”

Product designers are formulating for common health issues. “The key concerns of today’s consumer include satiety, heart health, women’s health, and overall health and well-being,” says Joe Richardson, senior research applications scientist, ADM, Decatur, IL. He says manufacturers could answer satiety demands with protein and dietary fiber. Heart health could come from fiber, omega-3 fatty acids and phytosterols. Isoflavones and calcium fortification cover women’s health, and you can get overall nutrition from vitamins and minerals.

A dynamic medium

Fortifying ready-to-drink (RTD) beverages can be difficult. “Those nutrients are chemicals,” says Ram Chaudhari, senior vice president, R&D, Fortitech Inc., Schenectady, NY. “They’re going to interact. And the vehicle—water—is there. Water is a good medium for interactions.”

Risks to product quality and stability are legion. “Any key nutrient can settle or precipitate out of solution due to improper hydration or interaction with a major nutrient compound within the finished-product formulation,” notes Richardson. Because many nutrients are notoriously heat-sensitive, extreme heat treatment, and other reactions during processing and storage, can cut into a beverage’s nutritional value. “Other chemical and physical factors, such as stress upon product package during distribution, heat from processing and storage of product, acidity, and the rate of oxygen permeation into the package, will affect the degree of reactivity with individual nutrients or other compounds.”

Flavor, color and texture all can take a hit, notes Lisa Bradford, soy foods technologist II, ADM. “A beverage developer has to be aware that texture is affected by the presence of protein or fiber, which can potentially contribute to thickness and grittiness,” she says. “Free ions are major reactive compounds with proteins or other chemicals, which impacts flavor and color within a finished beverage.” Bound mineral forms can sidestep the problem. “And, fortifying with specific forms of some minerals, such as ferric iron or ferrous iron with vitamins, affects products that are naturally colored and flavored,” she says.

Satisfaction, guaranteed

“For many years, whey proteins have had a following among athletes and bodybuilders,” notes Starla J. Paulsen, R&D manager, Glanbia Nutritionals, Inc., Monroe, WI. “In recent years—think protein water—this popularity has been spreading to other everyday health-and-wellness seekers. Whey proteins contribute to a beverage’s overall nutritional appeal, as well as enhance formulations with functional benefits.

“As beverages have gotten more complicated, we’ve gotten better knowledge about what proteins do and how to manipulate them in the plant,” continues Paulsen. Improved membrane filtration allows suppliers to tease out protein fractions better-suited to specific applications. “What has really made a difference for us is having the ability and flexibility to move the different whey protein streams around in the plant so that we can find the functionality that works really well at a neutral pH, for example, and another fraction that’s better for another product,” she says.

Neutral beverages run from meal-replacement shakes and high-protein supplements to dairy drinks. “They are usually UHT or retort-processed for shelf stability,” Paulsen says, “and can include a wide variety of other ingredients, especially vitamins and minerals.” But neutrality induces gel formation in whey proteins, especially when protein concentrations top 6%.

Manufacturers need to pick their proteins wisely. “Choose one that has a reduced water-binding capacity, such as a hydrolyzed version,” Paulsen says. Hydrolysis shortens the peptides to make them less likely to form water-binding networks. “And, if the protein cannot bind water,” she says, “it will stay fluid through processing.” Stabilizers—especially carrageenan—and citrate and sodium phosphate buffers protect whey proteins at neutral pH. “And, finally, homogenization during processing may be needed to create the desired texture when using higher protein levels,” she says.

“We’ve made so many leaps and bounds with the functionality of whey proteins that we see beverages on the market that will work out to 10% protein, which is a lot,” Pauslen says. “It used to be a wing and prayer to get in 3.5%.” For acidic high-protein sports drinks, isotonics and protein-fortified waters, fortification comes easier.

“Whey protein has a unique functionality over all proteins in that it is soluble and goes clear at low pH,” Paulsen explains. The trick to maintaining this solubility is to keep that protein-pH ratio in check: “If you push that protein level up, then you’ve got to bring that pH down.”

The major issue at this pH becomes increased astringency with decreased pH. “This is not usually a desired property for beverages,” Paulsen says. She suggests preacidified whey, and adds that “you can also use masking flavors. The trick is to work with your acid profile. You use different acids—phosphoric, citric—to get the right profile to go with the flavors that you’re using.”

Heat-induced gelation might occur if the protein-pH balance goes out of whack. “So, for example, a 2% protein beverage could be processed at pH 3.0,” Paulsen says, “whereas a 7% protein beverage would need to be at pH 2.7.” At levels around 8%, beverages develop thicker viscosities and age gelation. “And that’s a lot of protein—you’re talking about 40 to 45 grams of protein per 16-oz. bottle,” she notes. Bodybuilding products aside, protein waters tend to have around 5 grams of whey protein per 16 oz.

Intermediate-pH beverages comprise everything from smoothies and drinkable yogurts to juices. “It’s the category in which most all beverages fall,” says Paulsen. “This is the pH range that is most pleasing to consumers. And it’s the most technically challenging to fortify with whey proteins.” Protein’s isoelectric point typically falls between pH 3.8 to 5.3, causing it to generally precipitate out of solution, because it loses its charge within that range.

Fiber that flows

“The development of new techniques for separating, hydrolyzing and purifying new fiber ingredients has greatly expanded the options for fiber fortification in beverage applications,” says Lorraine Niba, Ph.D., business development manager, nutrition, National Starch Food Innovation, Bridgewater, NJ. “Soluble fibers can now be included in clear beverages, dairy products and instant mixes.”

In the past, the principal hurdles were solubility, dispersibility, and—especially in transparent applications—clarity. “Very few fibers remain clear in solution without lumping or globbing,” Niba says. “Fiber fortification of low-pH, clear beverages like apple juice also requires a fiber that is not hydrolyzed by acid.” In smoothie-type beverages, fibers must withstand high-shear processing without developing significant viscosity.

“We can now include the benefits of soluble fiber in clear formulas while avoiding things that consumers don’t like, such as off flavor notes and digestive intolerance,” Niba says. “And we have the ability to produce inert fiber to avoid negative impacts on shelf life, and to ensure that the fiber does not complex with other components during storage. It is possible to achieve very high levels of fiber in food systems. In fact, in beverages, fortification levels of up to 20% or more are possible without sedimentation.”

Today’s fibers can even improve sensory profiles. “A number of beverage formulas with relatively low levels of sucrose or fat may have uninspiring mouthfeel attributes,” says Niba. “Dextrin-based soluble fiber brings back desirable mouthfeel and texture attributes.” Her company’s soluble, prebiotic fiber made from agglomerated dextrin disperses readily in water and tolerates pasteurization, low pH and freezing. She recommends levels of 1% to 3% in beverages and shakes. At these levels, manufacturers can easily make “good source” and “excellent source” fiber claims.

As Pam Stauffer, global marketing programs and communications manager, Cargill Health & Food Technologies, Wayzata, MN, reminds us, “there really are options for customers to put fiber in beverages, which doesn’t really feel intuitive. But we can make it work.”

Oil and water

FDA allows low-saturated-fat and low-cholesterol products with at least 0.4 grams of phytosterols per serving to state that, when eaten twice a day with meals as part of a diet low in saturated fat and cholesterol, for a daily intake of at least 0.8 grams of phytosterols, they may reduce the risk of heart disease.

Getting 0.4 grams per serving is doable in beverages, notes Carol Lowry, senior applications scientist, Cargill Health & Food Technologies. “The volume of a beverage serving is 8 oz. or more, so 0.4 grams is a reasonable percentage of the formula to work with,” she says. “We’ve seen it go as high as 1 gram per serving. And studies have shown that higher levels are still safe and efficacious.”

Emulsifying the sterol makes it more soluble, Lowry says. This renders formulation simpler, as does using a powdered delivery method. It can be blended in with the other dry ingredients, and doesn’t require prehydration. “You want to stay away from creating a foam, because the sterol has an affinity for foam,” she says, which can develop in dairy and soy-based beverages. “So you can use high shear to get the ingredient in, but use it quickly and then turn it off.”

These sophisticated phytosterol ingredients have no marked effect on flavor or, when emulsified, on texture (the free sterol can feel gritty in certain applications, Lowry notes). But the ingredient remains visible in clear applications, and it has a whitening effect in darker drinks. Dairy, citrus juices and smoothies are a good fit.

Oceans aplenty

Long-chain omega-3 fatty acids—especially docosahexaenoic acid (DHA)—capture older consumers’ attention because “as the boomer population ages,” explains Artman, “memory loss and brain health are major concerns. DHA is a major structural fat in the brain and retina. It is also a key component of the heart. Numerous studies confirm that everyone—from infants to adults—benefits from an adequate supply of DHA.”

Light, temperature and transition metals “can influence the rate of omega-3 oxidation and, thus, the shelf life of the finished product,” Artman continues. “Proper handling and careful formulation can significantly improve the oxidative stability of beverages containing omega-3 oils.”

To work the fatty acid into a beverage, “you need to make the oils into an emulsion,” Artman says. “Due to the technological advances, a clear emulsion using nanotechnology can be produced. In other words, you can add this emulsion to water and still maintain the clarity of water or other clear beverages, like teas or clear juices.” However, the tiny particles’ surface-to-volume ratio is large enough to exacerbate photo-oxidation.

Kimberly J. Decker, a California-based technical writer, has a B.S. in consumer food science with a minor in English from the University of California, Davis. She lives in the San Francisco Bay area, where she enjoys eating and writing about food. You can reach her at [email protected].

Strong, Functional Growth

The Beverage Marketing Corporation, New York, has noted a steady 10%-plus per annum growth in functional-beverage sales since 1998, with wholesale tickets crossing the $4 billion mark way back in 2003.

And, according to a survey from the Natural Marketing Institute, Harleysville, PA, funded by PURAC North America, Inc., Lincolnshire, IL, almost one-quarter of today’s consumers (23.3%) tap into a fortified beverage at least once a day, while a similar proportion (23.7%) takes a gulp one to six times per week.