Starches and Gums: A Thousand and One Functions

Before World War II, starches and gums were a scant part of the American diet. Today they are in just about every processed food mainstream consumers eat. So prevalent are they on food labels, most of us ingest them with only a peripheral glimmer of awareness. Just as cars come with seat belts and pay checks with deductions, modern-day canned soups, cake mixes and sodas are tagged with gums and starches. The substances are best known as powerful thickeners but perform an extraordinary number of other functions essential to food quality. They impart food texture and structure, and they play a role in flavor release, appearance and shelf stability. In recent years, starches and gums have been recognized as healthy sources of fiber as well.

A traditional use of thickeners in the home occurs before Thanksgiving dinner: Cornstarch or flour is stirred into pan drippings over heat, and the mixture thickens into gravy. In professional food manufacturing, a plethora of starches and gums are available to achieve similar yet highly specific results. Bridgewater, N.J.-based National Food & Starch offers more than 360 different starches. "People ask, 'Why do you have 360,'" said Joe Lombardi, marketing programs manager for the company's Natural Polymers Group. "What's difficult is you might have five people making soups or yogurts, and each one has a different processing requirement because no two processes are alike. You select the starches to suit the process. They can't thicken too early in the process or it will slow down the equipment, and you want the right end-product quality. It's quite fascinating, really."

Along with processing variables, gum and starch selection is based on their particular talent with a food. For example, gum arabic is an excellent water-soluble emulsifier that keeps beverage ingredients finely suspended. "Whenever you drink a product like Coke or Pepsi, it has gum arabic in there," said Richard Lamb, technical director for White Bear Lake, Minn.-based Larex. "The emulsifer keeps it all even. If it wasn't in there, you would end up with layers of stuff." Locust bean gum is often used in ice creams to create a smooth meltdown and help in heat resistance. Xanthan gum is a typical ingredient in salad dressings, giving it the viscosity it needs in the bottle and the "clingability" desired when poured on salad.

Gums are important texture modifiers, explained Thomas West Jr., technical services manager of Jungbunzlauer Inc.'s operations in New Center, Mass. "For instance, some of the energy beverages may have soy powders or something similar that doesn't dissolve," he said. "Some gums in there make it a whole lot more palatable. They allow the scratchy particles to slide."

As mighty moisture managers, starches and gums are also important substitutes in low-fat foods. "Fats add a lot of functionality to a product," West said. "They add mouth feel, lubricity, eating qualities, tenderness. So when you take out the fat, you have to put something back in. You can't just put water and flour back in, or you go from eating something crumbly to eating something dry like a cracker." Similarly, when sugar is taken out of a product, the bulk must usually be compensated for.

Good, Healthy Fiber

Gums and starches are now recognized as healthy sources of dietary fiber. Gums are 80 percent soluble fiber, which binds cholesterol and helps lower its presence in the blood stream, said Florian Ward, Ph.D., vice president of research and development for Belcamp, Md.-based TIC Gums. "This is something that some companies are doing now. They are adding gums like guar and acacia in a beverage or any particular product to increase fiber content," she said. The soluble fibers also improve gut health, boosting microflora in the large intestine, Lamb said. Gums act as bulking agents as well, moving through the gastrointestinal system to help normalize bowl function. Digestion-resistant starches, such as those found in bananas and lentils, likewise are sources of fiber and contribute to healthy digestion. National Starch created a resistant-starch product, Novelose^®, to improve the texture and eating qualities of fiber-fortified foods. And Larex has developed larch arabinogalactan, a natural polymer, to provide both texture and tasteless fiber to foods.

In their native forms, starches and gums are natural. Starches, however, are nutritional energy sources while gums pass through the body as a fiber and are perceived by scientists as noncaloric, Ward said. The two also differ in usage amounts. Minor quantities of gum are needed to thicken--a ratio of 1-to-200 is enough to create a thick sauce or paste, Ward said. "They are functional at low levels and that is a unique characteristic. For starches you need as much as 5 percent." On the flipside, gums' potency demands they be used in small amounts. "If you try to develop too much viscosity with gums by using them at higher levels, typically the textural qualities are not desirable--they are slimy or 'snotty,'" Lombardi said. "When you think of starches, you think of a heavy, smooth texture." Because of the different functions they provide, starches and gums are not usually seen as competing ingredients and are sometimes used in conjunction with each other.

Natural vs. Modified

"Most gums were discovered by accident and then man learned to use them," Florin said. "Seaweeds--like agar and alginate--are gums. They are obtained from the sea. They are natural products. What man has done is extract this gum and polysaccharide and purified it." Polysaccharides are huge, complicated chains of molecules that make up starches and gums. In water-soluble form, they are also known as hydrocolloids.

Many natural forms of gums and starches are undeniably effective in crafting food products. But scientists have developed modified versions with vastly increased functionality--they stand up to different processing methods, prolong shelf life, improve frozen-food quality, etc. In the natural foods market, however, manufacturers want to avoid modified starches and gums. Label appeal is negative and the presence of chemically modified ingredients is contrary to industry philosophy. But the limited functionality of a native gum or starch could prove to be a problem as the health-food market grows. Smaller manufacturers faced with increased production and distribution to meet demand may find it necessary to explore different ingredients that can extend shelf life and bear rigorous processing.

Lombardi considers it an inevitability the organic market will continue to grow. The improved availability of organic products in mass-market stores is accelerating demand, he said. In response to the changing market here and in Europe, National Starch developed Novation^®, a series of unmodified food starches that have high processing tolerances, similar to those of modified starches. Novation has been approved for use in foods labeled as "organic" or "made with organic ingredients" but not "100-percent organic." It appears on labels as simply "cornstarch" or "tapioca starch," or whatever the selected natural base is. "We are pursuing 100 percent organic versions of the product as well, primarily because having a product on the National List does limit you to the usage restrictions for labeling," Lombardi said, adding starch is restricted to 5 percent in organic products. The only thickeners now classified as 100-percent organic are some gums and cornstarch, which is notoriously unstable.

TIC is among those companies offering some modified gums with increased functionality. "The idea is to improve on nature, to make the properties more constant," Ward said. TIC always informs its customers which gums are native and modified, and Ward advises food manufacturers to make sure they know what they are getting from their gum providers. "Labeling problems have been a concern with plant extractions and gums," she said. "You should ask for a certification if it is natural--no preservatives added. Sometimes you have to ask because it's possible that preservatives may end up part of the processing conditions, and they have to make that clear."

Industry Lacks Expertise

Manufacturers who want to be key players in the growth of the natural and organic foods industry are advised to improve their food-science knowledge and be adaptable to the changing market. "A lot of the organic foods I see out there, they have a good list of ingredients but are not particularly functional sometimes--they don't have the finish of a more thoroughly manufactured product," West noted. Lombardi agreed that mainstream consumers often are put off by the poor texture and flavor of many natural products. The lack of organic manufacturers' expertise on food ingredients is leaving the door open for savvy mainstream food manufacturers to capitalize on the organic trend.

"I think there is a lot more sophistication coming to the leaders of the industry--the Hains, the Worthingtons, the Cascadian Farms," Lombardi said. "They are learning to make the leap, to say, 'I can make clean-label, healthy, natural and organic foods and meet the demands of a wider range of consumers.' I think those people are going to be the ones that are going to grow and be the leaders in the industry."

Lombardi said some segments of the organic industry are resistant to change of any kind because they equivocate it with sacrificing their commitment to a higher goal. Others are satisfied with the status quo and have no wish to expand. "My advice to the organic food manufacturer is, if you want to grow, you need to understand what mainstream consumers expect from a flavor and texture standpoint--what they are used to," he said. "There are ways to make your products meet those needs rather than saying, 'This is what we've got. You should buy it because it's good for you.' Don't expect demand to be there just because a product is perceived to be cleaner or organic. Research what is out there."