Issue Date: October 31, 2011 | Web Date: October 30, 2011
Call In The Food Fixers
Keywords: food, food chemistry, beverages, texture, flavor, specialty chemicals
Alginates are polysaccharides derived from brown seaweeds. They are used for thickening, stabilizing, gelling, and film forming in foods such as cream and fruit fillings, salad dressings, ice cream, low-fat spreads, restructured meats, and yogurt.
Carrageenans are carbohydrates extracted from red seaweeds. Used for gelling, thickening, and stabilizing, they are often found in ice cream, coffee whiteners, cottage cheese, and low- or no-fat salad dressings. They are also used to suspend cocoa in chocolate milk.
Microcrystalline cellulose is a purified, partially depolymerized cellulose derived from tree pulp. It forms a stable gel that provides creaminess and cling to salad dressings, sauces, batters, fillings, icings, and low-fat sour cream. It prevents fried foods from becoming soggy and helps stabilize whipped toppings and chocolate drinks.
Methylcellulose and hydroxypropyl methylcellulose are derived from tree pulp. They provide thermal gelling properties that reduce oil uptake in fried foods and improve the texture of meat alternatives. They can be used to improve the “mouth feel” of sugar-free beverages and reduce milk fat in whipped toppings and desserts. A new use is to help trap air in gluten-free foods.
Cellulose gum, or carboxymethylcellulose, is made from fibers removed from tree pulp and cotton. It helps retain moisture in frozen dough, tortillas, and cakes and reduces fat uptake in doughnuts. It stabilizes proteins in protein drinks and replaces texture lost when reducing sugar in beverages. Cellulose gum adds viscosity, flow, and glossy appearance to low-fat sauces.
Gelatin is derived from the collagen in pig and cattle skins and bones. It is used as a gelling agent, stabilizer, thickener, and texturizer in desserts, yogurt, and low-fat foods.
Guar gum, a polysaccharide, comes from the seeds of the guar gum bush, Cyamopsis tetragonolobus, which is an annual leguminous plant that originated in India. As a thickener, it is eight times more powerful than cornstarch. It controls moisture and adds texture to baked goods. It also controls viscosity in dairy drinks, salad dressings, and condiments.
Pectin is extracted from the peels of citrus fruits and from sugar beets. It is used for gelling, thickening, and stabilizing food. Pectin derived from sugar beets does not form a gel but is used for stabilizing and emulsifying. Pectin is used in jams, jellies, fillings, and confectioneries. It can also be used to thicken and stabilize fruit- and milk-based beverages.
Starch is generally derived from corn, potatoes, or tapioca. Food makers use both native and modified versions. Starch can be hydrolyzed into dextrins such as maltodextrin. Starches are used as thickeners, stabilizers, and fat replacers in puddings, sauces, and salad dressings. They are often added to grain-based foods such as breads, cereals, tortillas, and pasta.
Xanthan gum is made by industrial fermentation of sugar by the bacteria Xanthomonas campestris. Used in small amounts, it adds viscosity and cling to salad dressings and sauces. It is also used in egg substitutes and in gluten-free baking.
Alginates are also used for textile printing, papermaking, and as lubricant stabilizers for welding.
Carrageenans are also found in toothpaste, air fresheners, cosmetics, paints, and emulsions.
Microcrystalline cellulose is also a common excipient in pharmaceutical tablets.
Methylcellulose and hydroxypropyl methylcellulose also help thicken shampoo, hairstyling products, body wash, lotions, and creams.
Carboxymethylcellulose is also used in papermaking, personal care products, drilling fluids for oil and gas, binders for building products, and pharmaceutical excipients.
Gelatin is also used to make pharmaceutical capsules, photographic films and paper, and cosmetics.
Guar gum is also found in toothpaste, shampoo, pharmaceuticals, and papermaking. Modified guar gum is also used in the construction and textile industries and in oil and gas drilling fluids.
Pectin is also used in ointments, oils and creams, shampoos, and conditioners. It is also found in bandages designed to promote wound healing.
Starch also acts as an adhesive in papermaking. It is also used as a pharmaceutical excipient and tablet disintegrant.
Xanthan gum is also used in drilling muds, including for horizontal fracturing for oil and gas. It is also used in cosmetics, pigment suspensions, water-based metal and timber treatments, and adhesives.
Consumers navigating the aisles of their neighborhood grocery store are routinely confronted with food labels shouting what is not in the product: fat, sugar, gluten.
The product claims appear from one end of the store to the other on beverages, salad dressings, sauces, cookies, and even bread. What shoppers may not know is that whenever fats, sugars, or gluten are taken out, a precisely tailored combination of other ingredients is called upon to replace them. These ingredients help food scientists make “light” or “-free” versions of products taste as close to the original version as possible.
Usually, it is texture they are looking to replicate. Take Hidden Valley ranch salad dressing: The light version of the iconic brand contains 40% fewer calories and 50% less fat than the regular dressing. The label additionally promises “Betcha can’t tell it’s light!” The reason it might be hard to tell is that the ingredients include modified food starch, carrageenan, and xanthan gum, rather than oil and sour cream.
“We have to add ingredients to build up the viscosity and give that creamy mouth feel,” says HV Food Products food scientist Edith Neta. “To get the right viscosity, we have to use more than one texturizing ingredient—they have synergistic activity.” She explains that each input has different properties. For example, starch thickens products. In contrast, “With xanthan gum, when you shake the bottle, the dressing flows. But when it’s on the salad it will cling to the lettuce. It’s also good for dipping; it helps the dressing stay on your carrot.”
To make sure consumers won’t miss what’s missing, food makers can choose from a long list of texture-improving additives and replacements—from agar to xanthan gum—and they normally choose several. The functional ingredients may come from specialty chemical companies or from firms devoted to food ingredients.
Yet if names like modified food starch and carrageenan sound familiar, it’s because no new texture additives have entered the market for decades. “Research and development has focused more on differentiation than on totally new products,” says Dennis Seisun, owner of the hydrocolloid consulting firm IMR International. “It would be way too expensive to get full approval for a brand-new product.” Instead, Seisun explains, ingredient firms create their “new” products by developing new properties from existing sources.
Although many ingredients are made with the help of chemistry, food makers are facing a consumer backlash against ones that appear to be chemically altered. Similarly, long, complicated lists of ingredients are falling out of favor. Ingredient suppliers are playing a big role in helping customers balance health claims, good taste, and consumers’ desire for “natural” foods.
The majority of textural replacement ingredients fall into a category of products called hydrocolloids, named for their ability to hold on to, and control the migration of, water in foods and beverages. The global market for hydrocolloids used in food was worth $5.8 billion in 2010, Seisun estimates. Close to half of that value was claimed by two hydrocolloids: starches and gelatin.
The other half of the market consisted of carrageenan and alginates, both derived from seaweed; cellulose, derived from tree pulp and cotton; other plant-derived substances such as pectin and guar gum; and xanthan gum from bacterial fermentation.
Seisun estimates that 1.4 million tons of hydrocolloids was consumed worldwide in 2010. Of that amount, 73% was starch. Asia in general, and China in particular, is a growing market for hydrocolloids, Seisun says, but it is difficult to get information on ingredients made in China for domestic consumption.
The market for hydrocolloids as a whole has a growth rate of nearly 3% a year, but rates for specific hydrocolloids vary from 1.5 to 2.0% for starch and gelatin to 5.5 to 6.0% for xanthan, pectin, and specialized forms of cellulose. Ingredients such as xanthan and carrageenan are more potent than the bulky starches and gelatins and command correspondingly higher prices.
Modifying food texture is an important application and area of research at ingredient firm National Starch, part of Corn Products International. The company provides starches derived from corn, potatoes, and tapioca. It also has introduced new texture systems that add precise creaminess and cling. “We have dial-in texture capability,” boasts Suzanne Mutz-Darwell, senior market development manager for texture at National Starch.
The primary job of starch is to be a thickener in the presence of water. Most starches have to be cooked to be functionalized. However, National Starch also makes instant and modified starches. In addition to bulking up a food, starch ingredients help manage water and prevent syneresis, which is the migration of water to the surface of a food. Water migration can happen when temperatures change or as proteins or carbohydrates bond more tightly to themselves and squeeze out water.
One common use of starch-based food ingredients is replacing a portion of fat, including fat from dairy, in sauces and other products. “If a customer has a high-fat, creamy sauce like Alfredo, they know that a lot of people love the indulgent experience but avoid it because of saturated fat and calories. It may be 19 to 20% heavy cream,” Mutz-Darwell points out. Customers may want to create a version with only 10% cream, or possibly none.
Fats and oils impart a number of textural attributes, and National Starch food scientists track them all to make sure new formulas match the original, or target, recipe. “When removing fat or oil, we want to know what it contributed to the eating experience as well as the goals and restrictions of the new product,” Mutz-Darwell says. Then National Starch formulators get to work. “We build back lubricity, mouth coating, how it melts away—because fat melts—creaminess, and oral viscosity. We include what’s left in your mouth and how quickly it clears your palate.”
Mutz-Darwell stresses that nine of 10 food product introductions will fail in the marketplace, and the wrong texture can spell doom for a new item. Texture is important not only to give food the right feel but also because a change to any textural ingredient will also alter a product’s flavor. So it’s no surprise that food makers desire an objective means of measuring texture.
“We characterize the benchmark product with a panel of sensory experts who describe and evaluate attributes of a food on a 15-point scale,” Mutz-Darwell explains. To do this, the company has developed its own texture language. One client wanted its baked potato chip to be halfway between crunchy and crispy, or “crinchy.”
To these descriptions, the company adds laboratory data. “We do rheological tests for flow behavior, dynamic viscosity, gel strength, hardness, and breakage—a large number of attributes. We can see which correlate with different sensory attributes,” Mutz-Darwell says.
The next horizon for starch is gluten-free foods. It is relatively easy to mimic the properties of wheat flour in products such as cookies, but bread is a challenge, according to Mutz-Darwell. “For bread, gluten is the backbone. Getting it to be soft and chewy requires trapping air, which is difficult.” Another tricky application is microwavable pizza dough, which needs to be crisp, even without baking.
Many starches for food use are modified chemically, physically, or enzymatically. Maltodextrin is a common enzyme-treated starch. When a food label lists modified food starch, it generally refers to starch that has been chemically treated to prevent retrogradation, when the amylopectin molecules gel or recrystallize, changing the food’s viscosity.
But some consumers avoid modified food starch, so National Starch sells a line of native starches, including some that are certified organic. They have functional properties similar to modified starches but are priced at a premium. One reason they cost more is to pay for the tracking of nongenetically modified raw materials.
Although starch-based ingredients take the lead by volume, manufacturers of other texture aids are looking for market share. “We’re taking a run at the starch players,” says Jane Schulenburg, global marketing director at CP Kelco, a hydrocolloid maker owned by J.M. Huber. Yes, starch is much cheaper by the pound, but “you can get a truckload of starch or just a pallet of gellan gum” to achieve the same effect, she says.
Gellan gum, introduced in the 1980s, is still considered one of the newest texturizing ingredients. It is a polysaccharide made by the fermentation of sugar by Sphingomonas elodea, bacterium originally isolated from lily pads. Often used in flavored beverages, gellan adds a fluid gel structure that can suspend particulates without adding significant viscosity.
But CP Kelco is best known for an older product. In 1959, while part of Merck & Co., it introduced xanthan gum, which like gellan is derived from industrial bacterial fermentation. The bacteria, Xanthomonas campestris, was discovered on leaves of the cabbage plant, where it secretes a polysaccharide that keeps the plant from drying out in drought conditions. Unlike gellan, which has a weak gel structure, xanthan adds viscosity at very small doses.
Gellan and xanthan gum sound newfangled compared with CP Kelco’s current push with an ingredient familiar to grandmothers: pectin. The ubiquitous jam and jelly helper is moving in on gelatin, the second most commonly used hydrocolloid after starch.
Pectin is extracted from the white pith inside citrus peels, whereas gelatin is commonly derived from animal sources of collagen such as skin from pigs and cows. CP Kelco also makes pectin from sugar beets. The use of pectin to replace gelatin stems from the rise of vegetarianism and from “consumers who have become more educated down to the end of the ingredients list,” Schulenburg says.
Pectin is finding applications in yogurt, where gelatin commonly appears, and in yogurt drinks, where its hydrocolloid properties act as a protein protector, allowing acidic fruit juices to coexist with milk proteins. “The blue-eyed boy is pectin now,” Seisun says. “It is the favorite in terms of consumer image, and you cannot overestimate the importance of consumer image.”
Still, food trends on their own don’t change the fortunes of a particular food ingredient. “We have to consider not only the end product but what’s in the middle—the manufacturers’ processing constraints,” Schulenburg points out. Food ingredients may need to survive pasteurization, provide long shelf life, and live through wide temperature fluctuations during shipping.
Food makers also look to control costs. Many texture-enhancing ingredients can take the place of more expensive ingredients such as dairy products. But food makers that want the labeling benefits of a natural-sounding ingredient will pay more. For example, pectin is both CP Kelco’s most expensive ingredient by weight and one of its fastest-growing products.
At FMC, growing demand for natural ingredients is an opportunity for its biopolymers business. A chemical company that also produces soda ash and lithium chemicals, FMC makes plant-derived food ingredients such as carrageenan, alginates, and cellulose gel.
Carrageenan, like its seaweed cousins the alginates, is used for its gelling, thickening, and stabilizing properties. “Of all of these texture ingredients they rank very well because of their natural origin,” Seisun says. “Many of them have the possibility of being labeled organic” or genetically modified organism-free.
FMC makes carrageenan from a variety of red seaweeds. The company works with growers around the world to obtain the raw material. It is gathered, dried, and baled, then ground, sieved, and washed. Next, carrageenan is removed from the rest of the plant material with a hot extraction process. The resulting polysaccharide comes in three forms: kappa, iota, and lambda. Each has characteristic water solubility and gelling properties.
FMC entered the food ingredient market about 50 years ago when it introduced Avicel microcrystalline cellulose gel, points out Mary Clarke, food ingredients general manager for FMC BioPolymer.
Like starch, cellulose can be made to mimic the texture of fat. But it is also used in sugar-free beverages. “Without sugar, a beverage can feel like a water solution, which is much thinner. A lot of customers use Avicel as a sugar replacer when using an artificial sweetener,” Clarke says.
The raw material for Avicel is purified plant fiber, or α-cellulose, from tree pulp. Cellulose is not water soluble so it must be chemically processed to be used as a food ingredient. The processing hydrolyzes part of the fibrous material to remove amorphous regions, leaving crystalline bundles of microfibrils that form a gel. The gel can be made into powdered or colloidal microcrystalline cellulose.
With the help of in-house food and beverage experts, FMC’s customers often choose to use a combination of cellulose and carrageenan. The two are blended into beverages, especially chocolate milk and nondairy creamer. The resulting products have richer textures, particle suspension, flow characteristics, and wide temperature stability.
FMC has seven technical application laboratories in places such as São Paulo, Brazil, and Shanghai, where food scientists work directly with local customers. Company researchers also try to track early indicators of emerging trends. Currently, novel beverages are keeping them occupied.
“Coconut water is the hottest thing in beverage now. Our products are used in certain flavors, like chocolate, for suspension,” Clarke says. In Asia, milklike beverages based on grains such as oatmeal or with nuts are popular. “It’s very technically challenging, but we can stabilize grains and suspend ground-up peanuts or walnuts,” Clarke says.
FMC’s biopolymers business, which also serves the pharmaceutical ingredient industry, has grown steadily. Revenues reached $610 million last year, up from $409 million in 2006. FMC says it has the largest global market share for microcrystalline cellulose, carrageenan, and alginates.
Other chemical firms have recently gotten into the food texturing business through acquisitions. With its recent purchase of Danisco, DuPont now sells a long list of hydrocolloids including alginates, carrageenan, microcrystalline cellulose, cellulose gum, guar gum, locust bean gum, pectin, and xanthan gum.
Ashland, perhaps better known as the parent company of motor oil brand Valvoline, bought into food ingredients in 2008 with its purchase of Hercules. The company is now a supplier of cellulose products including methylcellulose, hydroxypropyl methylcellulose, and cellulose gum.
Methylcellulose, with its slight affinity for fat molecules, has applications for fried foods, according to Mary Jean Cash, technical service representative for Ashland’s specialty ingredient business. “There is a lot of interest in reducing fat uptake in fried foods, and methylcellulose will gel and reduce steam escape in fried food, which means less fat penetration,” she says. “It can also add stability to coatings or hold together a product like a filled appetizer.”
Cellulose-based ingredients begin as plants—either trees or cotton—but their use in foods requires chemical processing to make them soluble in water. The alteration may not be clear to consumers.
Although adding texture to products with reduced fat and sugar is a trend that ingredient makers can count on, consumers who scan labels to ascertain whether a food is “natural” will continue to face an uphill battle. There are no government standards that regulate the use of the words “natural” or “all natural.” Food ingredient lists are not as informative on the subject as some consumers might wish. For example, carboxymethylcellulose normally appears as cellulose gum on food labels. Chemically altered starch is listed as modified, but modified pectin is just listed as pectin.
“Yes, consumers are looking for natural ingredients. But you just don’t know,” points out Michael F. Jacobson, executive director for the advocacy group Center for Science in the Public Interest. “Something could be natural, where no chemical bonds are broken, but it’s gone through such an amount of processing that the term natural becomes almost like a religious doctrine. How do you determine natural versus unnatural?” Jacobson says textural ingredients—even modified ones—are not harmful, but they also don’t bring any health benefits. “Even with all these presumably safe ingredients, all too often you end up with junk. That is a big concern,” he asserts.
For the moment, the makers of Hidden Valley ranch dressing are siding with texture over short ingredient lists. “It’s always a consideration; we’re very careful in selecting our ingredients,” Neta says.
“We’re trying to stay very connected to what consumers want and don’t want in their products. But taste is king for us. We’d rather make some compromise like using modified food starch and xanthan gum than have a product that consumers won’t buy because they don’t like the taste.” ◾
- Chemical & Engineering News
- ISSN 0009-2347
- Copyright © American Chemical Society
The diagram shows the texture attributes the food scientists were blending into their alfredo sauce. You can see, for example, that to make it like full-fat sauce, it would have a high shine but low chalkiness.