Stabilizers are additives used to help maintain emulsions or prevent degeneration in beverages. Among the most common stabilizers are hydrocolloids (such as xanthan, gum arabic and gum acacia), modified starches, pectin, carrageenan, casein and inulin. The purpose of stabilizers is to add viscosity to enhance flavor and give body to a beverage. They also maintain emulsification, which prevents sedimentation by keeping additional ingredients suspended in the product.
Functional beverages may contain a range of add-ins, including vitamins, herbs and proteins. Stabilizers ensure the nutraceutical portion stays suspended, eliminating ingredient settling and gritty taste.
Hydrocolloids have many uses, according to John Keller, technical manager for Morristown, N.J.-based P.L. Thomas. "They can maintain emulsification, ensure clarity and enhance viscosity," he said. "They can help suspend ingredients such as fruit pulp or minerals and they are inherently nutraceutical because they provide soluble fiber."
In addition to their functional benefits, hydrocolloids also add soluble fiber to a product. "The industry has become increasingly conscious of the role for fiber application in products," Keller said. Greater intake of soluble fiber has been linked with reduced risk of many health conditions, including cardiovascular disease and some types of cancer.
There is a broad range of hydrocolloids, each with its own capabilities. CMC (sodium carboxymethylcellulose), for example, is a versatile ingredient that can add viscosity and mouthfeel, but is also clear in solution, enabling it to add functional properties without impacting clarity. Carrageenan, on the other hand, has excellent suspension properties and is interactive with dairy protein, but adds cloud.
Perhaps the best-known hydrocolloid for stabilization is xanthan gum. "If you were to buy one gum to fit all beverage applications, it would be xanthan," Keller said. Xanthan gum is cold soluble, has suspension and viscosity abilities, and has good acid stability. Gum arabic is also useful in stabilization, primarily for its ability to stabilize emulsions without adverse viscosity. This property also makes it useful for making instant spray-dried flavors to use in dry beverage mixes. Gum acacia, an exsudate from the acacia tree, also stabilizes emulsions and serves as a weighting agent.
While the hydrocolloids offer excellent properties, they do come with challenges. According to Keller, the primary challenges relate to dispersion and hydration. Because hydrocolloids are long-chain polymers, they are partially soluble and partially non-soluble. If the molecules of the gum are not separated efficiently, the outer surface will get wet and form clumps when added to liquids. To overcome the challenge, most formulators user various dispersion techniques, dropping the gum gradually into a vortex of liquid, or combining the gum with another substance, such as sugar or oil, to keep the particles separate.
There are many other types of stabilizers used for different application results. Modified starches, for example, are effective clouding agents and may stabilize turbidity under cold storage. Pectin is a compound found in the cell wall of many higher plants; it has natural jelling, thickening and stabilizing abilities. Pectin is a soluble fiber and in beverages serves to increase viscosity and stabilize cloud. Carrageenans are polysaccharides derived from certain types of red seaweed; it is used as a thickening agent. Casein is a dairy isolate, often used in spray-dried form; it affords emulsion stability to protein solutions, and has been found particularly helpful in stabilizing soy isolates.
Other stabilizer options include inherently functional products such as inulin and broader use food products such as weighting agents. Inulin is a natural, soluble fiber usually extracted from chicory. According to Scott Noar, Ph.D., manager of applications and technical services for Orafti Food Ingredients in Malvern, Pa., manufacturers are adding inulin to beverages for functional and nutritional reasons. Among the functional benefits are added flavor, mouthfeel and suspension.
Inulin's sweetness is similar to that of sucrose, ranging from 0 percent to 30 percent as sweet as sugar. It also interacts synergistically with high-intensity sweeteners, resulting in less aftertaste and a more balanced flavor. For suspension purposes, inulin can be used alone or in combination with gums. "Inulin aids gum-stabilized systems in three ways," Noar said. "It acts synergistically in gum systems to reduce costs by lowering gum use. It offers a more uniform viscosity. And, it improves emulsion stability."
Different nutraceutical ingredients require different stabilizers for beverage applications. Nutritional oils, for example, may be well served by weighting agents, traditionally designed to hold flavoring oils in suspension. According to Phil Cook, Ph.D., technical service manager with Kingsport, Tenn.-based Eastman Chemical, there are many possibilities for weighting agents in the nutraceutical market. "We anticipate seeing some enhanced use of weighting agents in any beverages that would contain oil-soluble ingredients," he said. "There is a need to make certain the oil is evenly dispersed and maintained throughout the product."
Weighting agents, such as Eastman's SAIB (sucrose acetate isobutyrate), work by enfolding the nutraceutical particles to control the density of the oils. While older versions of SAIB caused a fairly viscous solution, newer grades offer lower viscosity. "Low viscosity blends are a growing area," said Bobbi Buford, Eastman's market development manager. "Without the heavy viscosity, manufacturers can take advantage of the additional benefits such as a neutral flavor and even cloud."
