Food Product Design: Health/Nutrition - March 2005 - A Beverage A Day Keeps the Pounds Away

March 2005

A Beverage A Day Keeps the Pounds Away

By Karen GrenusContributing Editor

Some European friends once told me that Americans are easy to spot because they're so flabby. They might be on to something. According to data from the National Center for Health Statistics, Hyattsville, MD, from 1999 to 2002 64% of adults over 20 years old were overweight or obese. Because being overweight can lead to heart disease, cancer, diabetes and stroke, in a very real sense, we fight for our lives every time we attempt to lose weight.   

To combat growing waistlines, consumers often turn to diets. The 2004 Calorie Control Council National Consumer Survey reports that, currently, 71 million people are dieting. The Atkins, South Beach, Zone and Sugar Busters diets -- constructed around the balance of carbohydrates, protein, fat and fiber -- became popular regimens for those looking to shed weight. With today's culture of eating on the run, it follows that hand-held products that fit these and other routines increase the consumer's chance of success.

Weight-loss beverages are an ideal medium for hand-held, convenient nutrition. Ten years ago, they were, in effect, meal replacements that contained enough sugar to taste really good, enough fat to be creamy and a moderate amount of protein and fiber. Consumers lost weight primarily through calorie reduction. But today, consumers know about macronutrients, and are more likely to purchase products after looking at carbohydrates, net carbohydrates, protein, fat and fiber. This leaves developers to create a "delicious shake" while following guidelines that, at first glance, appear antithetical to that description.

The science of satiety A straightforward formula for weight loss doesn't exist. The body has a complex reaction to food: It involves all the senses, levels of nutrients in the bloodstream and digestive hormones. For a weight-loss beverage to achieve its purpose, it must taste good enough for consumption and be palatable; cause fullness during consumption, or satiation; cause a continued sense of fullness until the next meal, or satiety; and remain palatable over the course of the diet.

Of the macronutrients, protein wins in appetite reduction per calorie, followed by carbohydrates and fat. (A paper written by De Graaf, et al, and published in the June 2004 issue of the American Journal of Clinical Nutrition, provides a thorough discussion of this. Visit www.ajcn.org.)

One hormone that has been heavily researched with regard to appetite is cholecystokinin (CCK). When the stomach is full, CCK is released into the bloodstream and reduces appetite. But it isn't quite that simple, because other hormones will control the body's response to CCK. The relationship between fullness and satiety is the basis for energy density, an approach to appetite developed by Barbara Rolls, Ph.D., Pennsylvania State University, University Park. Energy density is the calorie content per volume of food. Rolls' research indicates that people can cut calories by replacing energy-dense foods with less-energy-dense ones, which will fill the stomach, resulting in the release of CCK, sending a signal to the brain to stop eating. High-moisture products, or those with incorporated air, such as shakes, address this way of eating.

Many popular diets are based on lowering the amount of glucose -- and the resulting insulin -- in the bloodstream. The glycemic index (GI) measures how ingesting a carbohydrate affects the blood-glucose level. By definition, glucose has a GI of 100. Formulators can develop weight-loss beverages with fewer carbohydrates, or use carbohydrates with lower GIs, in order to respond to the low-carb diet requirements.

A challenge in developing and marketing these beverages is that no uniform way of conveying the energy density or GI of a product to consumers exists. In the low-carb arena, "net carbs" has become a standard item on the label. To differentiate between the "good carbs" and the "bad carbs," net carbs was created as the total grams of carbohydrate minus the grams of sugar alcohols and fiber.

How sweet it is As the primary sweetener for centuries, sucrose is the gold standard in defining what a sweetener should taste and act like. It's also one of the first ingredients formulators look at for calorie reduction.

According to Bob Nelson, senior applications scientist for Flavors of North America, Carol Stream, IL, the perception of sucrose goes beyond its sweetness: "Sweeteners not only provide sweetness, but they all have a specific taste characteristic. Sugar has a definite taste; it doesn't taste like corn syrup, or like aspartame or sucralose. There also is a time factor in the staying power of the sucrose. The sweetness peaks and goes away, whereas the artificial sweetener can build and stay with you."

From a functional standpoint, the level of sucrose used in RTD beverages provides solids that contribute to suspension stability and viscosity. Therefore, the replacement of sucrose with a high-intensity sweetener must address mouthfeel as well as flavor. Nutritionally, sucrose and other natural sugars provide 4.0 kcal per gram.

Many low-carbohydrate products with "net carb" claims use sugar alcohols to replace sucrose. Maltitol is considered a low-GI food, with a GI less than 55. It is 90% as sweet as sucrose, but is a reduced-calorie sweetener at 2.1 kcal per gram. Ronald C. Deis, Ph.D., vice president of technology for SPI Polyols, Inc., New Castle, DE, explains that because maltitol is a disaccharide, it functionally behaves much like sucrose in terms of solubility, dispersion and osmolality. Consequently, like sugar, the polyol solids contribute to the beverage's viscosity and stability.

Deis advises that maltitol not be used at higher than 10 grams per serving to avoid laxation effects, which can occur if the consumer drinks multiple servings at a time. Developers can use maltitol in sweetened beverages where the level of sugar can be reduced and partially replaced with the polyol. For example, replacing half the sugar in a weight-loss beverage with maltitol reduces the calories from the sweeteners by almost 25%.

Tagatose, like polyols, is a reduced-calorie sweetener that contributes solids and sweetness to weight-loss beverages. Tagatose is 92% as sweet as sucrose, and provides 1.5 kcal per gram. It claims to have a minimal effect on blood-glucose levels, and acts as a prebiotic to supply healthy bacteria to the gut. Like most ingredients, tagatose impacts the flavor of other ingredients in the system. Tagatose is reportedly synergistic with some high-intensity sweeteners, and behaves as a flavor enhancer to some sweet flavors.

Beverage formulators can also choose from a number of high-intensity sweeteners. These ingredients are used at a small percentage of the traditional sweeteners they replace. The very low usage level results in a negligible contribution to calories. Since they do not add bulk to the formula, high-intensity sweeteners will not impart viscosity, stability or mouthfeel to the beverage.

Many of us grew up on diet soda sweetened with saccharin, which is 200 times as sweet as sucrose. In the late '70s, saccharin's safety was questioned after a study showed that rats developed cancer after being fed large quantities of the ingredient. However, the results sparked controversy and the weight of evidence showed that, at the current levels that saccharin is commonly consumed, no link to cancer exists. In 1997, the U.S. National Institutes of Health announced that its National Toxicology Program (NTP) reviewed data that could delist saccharin from the federal government's "Report on Carcinogens"; in 2000, the NTP released the 9th edition of the report and announced that saccharin had been delisted. And, in Feb. 2004, the American Dietetic Association, Chicago, took the position that saccharin is safe for consumption. Whether from its past notoriety or its bitter aftertaste, other newer, high-intensity sweeteners have overtaken the market lead.

One popular beverage sweetener is aspartame, which has been used since the early '90s. It's roughly 200 times as sweet as sucrose, and is available in granular, powder and liquid forms. According to the supplier's information sheet, the powder dissolves the most readily in acidic conditions at a temperature between 50?F and 70?F. The sweetener is most stable at a pH of 4.3, making it well suited for applications such as juice drinks. It is sensitive to heat, presenting shelf-life issues, a consideration in RTD applications. Aspartame also acts as an enhancer to citrus flavors.

Neotame is molecularly similar to aspartame, but is 8,000 times as sweet as sucrose. Studies testing neotame in beverages with HTST processing and pH values ranging from 3.2 to 6.5 revealed no significant loss of sweetness. Developers also can use neotame below the threshold for sweeteners as a flavor modifier in some applications, or in combination with sucrose to reduce the overall sweetener level while using the bulk of the sucrose.

Acesulfame potassium, or acesulfame K, is 200 times as sweet as sucrose, and also has a synergy with other sweeteners. "One of the best fixes on the market is Pepsi One," says Nelson. "When they combined aspartame and acesulfame K, they lowered the total sweetener, but the ingredients have a synergy that allows it to taste as sweet as it should and the lingering effects of aspartame are reduced."

Sucralose has burst onto the market to become the most-prolific sweetener in new, low-sugar products. Sucralose is a modification of the sucrose molecule, and is reported to taste very much like the real stuff. It is 600 times as sweet as sugar, and is very stable to processing. However, its rapid rise in popularity has led to one downside. According to a report on ABC News, Dec. 3, 2004 (http://abcnews.go.com): "Tate & Lyle PLC (headquartered in London) the world's only manufacturer of sucralose, said interest has so outpaced expectations the company won't take on new U.S. customers until it has doubled production at its plant in McIntosh, AL, sometime in early 2006."

Finally, the South American herb stevia also contributes high-intensity sweetness. However, it's classified as a dietary supplement by FDA, rather than a food ingredient or sweetener, and can only be in products labeled as such. The leaves can be crushed and dried for teas, or the powdered extract of the herb can be used in other beverage applications.

Don't forget the fat Fats and oils do wonders for the flavor and mouthfeel of food, and can be a component of weight-loss beverages for all but the very low-fat plans. To see the difference a small amount of fat makes, compare skim milk to milk with 1% fat. For shake-type products, such as French vanilla, milk chocolate and cappuccino, a small amount of added fat gives the product a desirable creaminess. In developing beverages for the health market, oils that have not been partially hydrogenated are preferred by those looking out for trans fatty acids. Monounsaturated fats, such as canola oil, might also lower blood cholesterol.

Fat is very energy dense, supplying 9 kcal per gram as opposed to 4 kcal per gram for carbohydrates and protein. For products intended for low-carb diets, fat on the label is not a bad thing. Per 11-oz. serving, the Slim-Fast Optima RTD shakes contain 5 grams of fat and the Atkins Advantage(TM) RTD shakes have 9 grams of fat. High-shear mixers, such as homogenizers, are required to reduce the oil to small droplets. The resulting emulsion is stabilized through the use of emulsifiers and gums.

In a joint venture between ADM, Decatur, IL, and the Kao Corporation of Japan, Enova(TM) oil is being brought into the U.S. market. Unlike other oils that are primarily made up of triacylglycerols, Enova oil contains 80% diacylglycerols. This oil is reported to function fully as a fat, but is metabolized differently due to the molecular shape. The specialty oil still delivers 9 kcal of energy per gram, but the diacylglycerol is metabolized and burned as energy instead of being carried to the bloodstream and stored. Enova oil has been successfully used in meal-replacement beverages as a substitute for other oils, and would have the same applications for the weight-loss market.  

More protein, please Protein has become a hot commodity of late, thanks in part to low-carb coverts. "Many beverages today are targeting ranges greater than 10 grams per serving," says Jean Heggie, marketing leader for the Solae Company, St. Louis. "This trend appears to be driven by the nutritional reality that protein is a very satiating nutrient and an important macronutrient in creating products optimized for satiety and hunger management."

In addition to contributing nutrition to a product, proteins also can add viscosity, emulsification, opacity and flavor. To optimize the attributes from the protein component of the beverage and minimize cost, product designers will often use a blend of proteins.

The major milk proteins are casein and whey. Caseins predominate, and they are separated from milk through acid precipitation. Caseinates are created through neutralization with a mineral salt, typically calcium, sodium or a combination of the two. The choice of acid casein, calcium caseinate, sodium calcium caseinate or sodium calcium depends on the desired functionality. For example, sodium caseinate assists in the emulsification and aeration of a beverage, lending itself to shakes and full-fat products, while calcium caseinate has a low viscosity and is very dispersible in water for applications with high levels of protein.

Whey, formerly a low-value byproduct of cheesemaking, has developed into a valuable functional ingredient. "Whey is a reliable source of high-quality and biologically active proteins and minerals, thus making it an ideal component for a variety of weight-loss products," says Marcela Cota Rivas, technical and nutritional development manager, Vitalus Nutrition Inc., Abbotsford, British Columbia. "Whey proteins contain various bioactive compounds that have a positive synergistic effect in weight management."

Among whey's health benefits are its high concentrations of branched-chain amino acids that protect lean muscle mass, glycomacropeptides (GMP) that stimulate the release of CCK to suppress appetite, and rich levels of minerals, including calcium, phosphorous, magnesium and zinc. In addition, its lactose has a low GI.

Cota Rivas also notes that whey proteins are soluble over a wide pH range, which is advantageous for beverage formulation. It is critical to select the right protein and stabilize it with emulsifiers to reduce aggregation of the protein due to heating. Agglomerated proteins can be used in drink-mix applications for ease of dispersion. "In order to obtain a clear, heat-stable whey protein drink, the main factors to be considered are the type of whey protein, pH, heat treatment -- including temperature -- and holding time, and ionic strength," she adds.  

Like whey, soy has health benefits beyond its value as a protein. A heart-health claim can be made for products that contain at least 6.25 grams of soy protein per serving and that are low in fat, saturated fat and cholesterol. In addition, "soy protein isolates, which are commonly used in such beverages, are over 90% protein on a dry basis, and are virtually carbohydrate-free. Soy protein concentrates are typically 70% protein on a dry-weight basis, and contribute dietary fiber as well. Both ingredient forms fit well in products that are designed to be 'low carb' or 'low net carb,'" says Heggie.

For weight-loss beverages with protein, Russ Egbert, director of protein research for ADM, notes: "With soy, and any of the proteins that are used in weight-loss drinks, you typically see the protein content on the order of 8 to 15 grams per serving. Some of the juice-based products tend to be lower, around 4 to 6 grams of protein per serving."

The selection of the soy protein will depend on the application. "For a RTD product, you are looking for proteins with high solubility to be soluble in that system and stay in suspension," Egbert says. "Depending on the product and the amount of protein you want to deliver, viscosity will be a consideration. If you want to deliver a high level of protein per serving, then you really have to use a low-viscosity protein." He also notes that drink mixes require soy proteins that are readily dispersible and have a high enough bulk density to fit in the desired package.

When using soy protein in a juice-based application, the low pH and low viscosity need special consideration. "Soy proteins increase viscosity, and they also are difficult to stabilize in acid environments," says Egbert. Beyond selecting the right protein, he explains that pectin is used in these applications, and when homogenized, it produces a stable suspension.

"There are different things that you have to do in terms of stabilization and processing to make sure that you get the best product you can produce," adds Egbert. "Most functional ingredients, like proteins and gums, are technical ingredients and require technical support."

Put the fiber in the mix Soluble and insoluble fiber have been linked to the reduction of blood cholesterol and certain cancers, respectively. There is no question that soluble and insoluble fibers should be a part of every healthy diet. In the event that grains, fruits and vegetables are replaced by weight-loss drinks, it's essential that fiber be incorporated into the beverage.

"Fibers are something that I think are being overlooked in the way of nutrient value," notes Alice Wilkinson, director of product development, Watson Foods Company, West Haven, CT. "Beverages are a great application because they can have dual function as a nutrient and stability system in RTD beverages. Soluble versus insoluble fibers are not terribly difficult to balance."

Product designers have a wide variety of fibers to choose from. Some of the considerations for beverage formulation include: flavor, mouthfeel and opacity, which affect product attributes, and dispersion, suspension and cost, which affect processing.  

"Soy fiber also provides unique health benefits," adds Heggie. "Derived from soybean cotyledon, Fibrim® soy fiber, in clinical studies, has demonstrated that it provides the heart-health benefits typically associated with soluble fibers and the digestive benefits typically associated with insoluble fibers. It is an excellent choice as a dietary-fiber source for weight-loss beverages." Like soy proteins, the soy fiber is available as a range of products for different beverage applications.

Polydextrose is a good choice when looking to replace the bulk of sucrose in the presence of high-intensity sweeteners. Polydextrose is nonsweet, contains only 1 kcal per gram, and the body treats it as a soluble fiber. Polydextrose can also act as a prebiotic that supports the growth of good bacteria in the gut. Donna Brooks, product manager for Danisco Sweeteners in Ardsley, NY, states: "As far as weight-loss beverages, Litesse® brand polydextrose is ideal for use in this type of application due to its low calorie content (1 kcal per gram), low glycemic index, its fiber properties and its potential to increase satiety based on clinical studies." The ingredient is soluble in water up to levels of 80%, so additional stabilizers are not needed to keep it suspended.

Inulin and fructooligosaccharides (FOS) can provide fiber, mainly soluble, as well as prebiotic effects, making them excellent candidates for weight-loss beverages. They pass through the mouth, stomach and small intestine without being metabolized and are fermented by bacteria in the colon resulting in a 1.5 kcal per gram contribution.

In a supplement to the Journal of Nutrition published in 1999, Kathy R. Niness of Orafti Active Foods Ingredients, Malvern, PA, explains that inulin is a blend of fructose polymers, and oligofructose is a subgroup with a degree of polymerization of less than 10. These ingredients occur naturally in a variety of fruits and vegetables. In the supplement, Niness states: "Most of the inulin and oligofructose commercially available on the industrial food-ingredient market today is either synthesized from sucrose or extracted from chicory roots."

In weight-loss beverage applications, oligofructose provides sweetness and body, whereas inulin is less sweet and imparts a creamy mouthfeel. The ingredients can serve as a partial or full replacement of fat and sugar. In addition to their benefits as a soluble fiber, inulin and oligofructose are prebiotics and do not cause an increase in blood-glucose levels. In the same paper, Niness describes a "high performance" inulin product that does not contain any oligofructose. This product has negligible sweetness and has improved functionality as a fat mimetic.

FOS molecules differ from inulin in chain length as noted. There is also a class of ingredients commonly known as short-chain fructooligosaccharides (scFOS) that are defined as a mixture of glucose-terminated fructose chains with a maximum chain length of 5 units. These are derived from sugarcane by natural fermentation. Products classified as scFOS are about 30% as sweet at sucrose, can mask off-flavors and provide 1.5 calories per gram.

The different chain length affects the functional characteristics of the product in specific applications. For example, inulin's longer chains make it less soluble, but it has the ability to form inulin microcrystals that act as a fat mimetic when sheared in water or milk.

Keeping it together Product developers use hydrocolloids in weight-loss beverages for viscosity, mouthfeel and suspension. They also can provide soluble fiber. In weight-loss formulations, microcrystalline cellulose can contribute significantly to palatability by mimicking the creaminess of fat and improving flavor release. On its website, FMC Biopolymer, Philadelphia, recommends adding a small amount of a protective hydrocolloid, such as xanthan, carboxymethylcellulose (CMC), or methylcellulose to acid applications with a pH value of less than 3.8 to prevent flocculation.

Carrageenan is widely used in milk-based applications because it forms a complex with the casein. CMC is well suited to juice-based applications due to its stability at low pH. Xanthan gum is a popular choice for harsh conditions, due to heat or acid, and is excellent in maintaining a suspension. To achieve the desired texture modification and stability, most often a blend of gums is needed to meet the product and process demands.

Building fortified beverages Adding a daily dose of vitamins and minerals to a weight-loss beverage is also doable. "Weight-loss beverages call for complex premixes with typically no less than 12 vitamins and minerals and may have as many as 30 different nutrients. The 'full complement' will include vitamins A, D, E, K, thiamin, riboflavin, pyridoxine, niacin, folic acid, B12, biotin and pantothenic acid. Typical minerals include calcium, magnesium, phosphorus, iodine, zinc, copper, iron, manganese, chromium, molybdenum and selenium," says Wilkinson.

She adds that the minerals used in large amounts are incorporated as micronized versions for better dispersion. Also, less-soluble sources, such as dicalcium phosphate, are used because they can reduce the impact of the mineral on the pH, taste and color of the beverage, and they can carry other ions that meet label claims. "Certain RTD products require the more-soluble sources -- for example, clear products -- but they take up more space. Ten percent daily value for calcium as calcium lactate requires 746 mg; whereas 10% daily value as calcium carbonate requires 250 mg and can cost much more," she says.

Wilkinson explains that RTD products will require larger overages of less-stable vitamins to compensate for loss during heat processing and storage. Powdered mixes have fewer issues with reaction among components, but ingredients such as citrate and chloride salts will contribute hygroscopicity to the blend.

"Every premix is truly customized based on the product, processing, packaging and shelf-life expectations," Wilkinson concludes.

Weight-loss ingredients There is no shortage of ingredients that claim to accelerate fat loss. Listed below is a sampling of products that are available for beverage applications. Many of these ingredients are GRAS for food applications. Weight-loss ingredients that are not GRAS but fall under the Dietary Health Supplement Health and Education Act are considered safe but are not as closely regulated by FDA. Proceed with care when choosing a source to verify the purity of the product, as well as its legal status, in the United States.

Conjugated linoleic acid (CLA) is a fatty acid that occurs naturally at low levels in meat and dairy products. Some claims indicate that it increases lean body mass, which enhances weight loss. Marianne O'Shea, Ph.D., senior nutrition manager, Lipid Nutrition, a division of Loders Croklaan, Channahon, IL, describes a study that shows consumption of at least 3 grams of Clarinol(TM) CLA a day was necessary to see this effect. She explains that the self-affirmed GRAS ingredient behaves like any polyunsaturated fat derived from sunflower oil.

Dairy products have also been linked to weight loss. To maximize that potential, Glanbia Nutritionals, Monroe, WI, has developed Prolibra(TM), a whey-protein-based ingredient that has been shown to help reduce body fat while maintaining muscle. In a study funded by Glanbia Nutritionals, consuming 26.5 grams of the ingredient in a beverage form once a day resulted in fat loss. Prolibra has GRAS status.

One vitamin said to reduce fat and cholesterol buildup is choline. It is naturally occurring in many foods, and is a component of lecithin. Wilkinson comments on the renewed interest in choline and notes that it "typically requires a fairly high dose, so you need to keep in mind that both the chloride and bitartrate versions are very hygroscopic and at high levels can impart a fishy note." Both choline chloride and choline bitartrate are listed as GRAS.

Chitosan, produced by the chitin from shells of crustaceans, acts as a dietary fiber and contributes no calories. Chitosan reportedly binds with fat, carrying it out of the body so it cannot be absorbed, reducing low-density lipids in the blood. Chitosan products that have GRAS status are available.

Energy boosters Caffeine, a natural stimulant, increases the amount of energy burned, and subsequently provides weight loss. Teas, such as green tea and yerba maté, contain caffeine as well as polyphenols and other active compounds that are said to support weight loss and overall health. Yerba maté is also believed to be an appetite suppressant, and the extract is often used in protein shakes.

Other research indicates that green-tea extract might increase the amount of energy burned, resulting in weight loss beyond any reduction in calories consumed. The extract is selected based on the amounts of polyphenols, catechins, caffeine and epigallocatechin gallate (EGCG), which is also a powerful antioxidant. Ingredients with caffeine or other alkaloids will be bitter to some degree and might be objectionable at the levels used.

Not all herbal products are safe to use. Ephedra, or ma huang, a stimulant that raises the metabolism in the presence of caffeine, was a popular component of weight-loss products in the past. However, ephedra use has been linked to deaths from heart attack and stroke. FDA prohibits the sale of products that contain ephedra.

Creating fantastic flavor Being stable and nutritionally sound is essential for weight-loss beverages, but repeat sales won't occur if the product doesn't taste good. Products formulated for health instead of taste need the magic of flavor houses to make drinking them a memorable experience. Flavors can mask undesired characteristics from added ingredients, enhance existing flavors and create the signature taste of weight-loss beverages.

Nelson says that product-specific masking flavors are a requirement in most nutraceutical products. "Bitterness is the most common negative attribute," he notes. "There are also off-notes caused by specific ingredients, such as proteins and sweeteners." A careful balance of ingredients is needed to minimize negative attributes. For example, increasing sweetness can help mask bitterness as long as any off-flavors from high-intensity sweeteners are kept in check.

Soy's notorious beany flavor has been tamed, but with use levels of more than 10 grams per serving, the flavor of soy protein needs to be addressed. "Soy still has a flavor, and while being continually improved upon, masking flavors are essential in everything we do and are available from all the major flavor suppliers today," says Egbert.

The flavor of the weight-loss beverage is impacted as the formulation moves away from balanced amounts of protein, fat and carbohydrates. Reducing the level of carbohydrates will impact mouthfeel, high protein levels will contribute undesirable amine notes, and lubricity and mouthfeel is lost as fat is reduced, Nelson explains. Masking flavors can help to cover up the off-flavors from protein and high-intensity sweeteners, and flavors can also "fool the palate into thinking that there is some fat in there," he adds.

In formulating weight-loss products, there are two overriding messages. First, most of the ingredients will impact more than one characteristic of the product and must be evaluated in the complete system. Second, the best ingredient to meet a particular need is usually a blend. The consumer is increasingly sophisticated in the areas of nutrition and flavor, and complexity in the formulation can please the palate.   

Karen Grenus, Ph.D., has eight years combined experience in applied research and product development in the area of dry blends for savory applications. She holds a doctorate degree from Purdue University.

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