A Beverage A Day Keeps the Pounds Away

Weight-loss beverages are an ideal medium for handheld, 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.

In addition to calorie reduction, then, 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.

One of the hot, and healthful, ingredients in weight-loss beverages is protein. “Many beverages today are targeting ranges greater than 10 grams per serving,” said Jean Heggie, marketing leader for the Solae Co., 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 nutritional value 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 desired functionality determines whether to use acid casein, calcium caseinate, sodium calcium caseinate or sodium calcium.

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, the other major milk protein, and formerly a low-value byproduct of cheese-making, has developed into a valuable functional ingredient. 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 the hormone cholecystokinin (CCK) to suppress appetite, and rich levels of minerals, including calcium, phosphorous, magnesium and zinc.

Like whey, soy, a plant-derived protein, has many health benefits beyond its protein content. 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 percent protein on a dry basis, and are virtually carbohydrate-free. Soy protein concentrates are typically 70 percent 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,’” said Heggie.

For weight-loss beverages with protein, Russ Egbert, director of protein research for ADM, noted: “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.”

Fiber Fix, 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 fiber-rich 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,” noted Alice Wilkinson, director of product development, Watson Foods Co. “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,” said 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, N.Y., stated: “ 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 percent, 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 weight-loss beverage applications, FOS 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.

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 percent 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.

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.

Bob Nelson, senior applications scientist for Flavors of North America, said product-specific masking flavors are a requirement in most nutraceutical products. “Bitterness is the most common negative attribute,” he noted. “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 mostly 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,” Egbert said.

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 said. 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 added.

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 from Purdue University.

Editor’s Note: The full version of this article originally appeared in the March 2005 issue of Food Product Design, a sister publication of Natural Products INSIDER. Get the complete version online at www.foodproductdesign.com/articles/465/465_0305HN.html.