Food Product Design: Applications - June 2004 - Taste-Bud Teasers and Flavor Tricks

June 2004

Taste-Bud Teasers and Flavor Tricks

By Donna BerryContributing Editor

Even pharmacists have caught on. Walk into any major pharmacy to purchase a fluid prescription and you will be asked: What flavor? Indeed, with the right additives, it is possible to trick the taste buds into finding something typically unpleasant tasting, into something, well, in the case of cough medicine, tolerable.

With foods and beverages, the result is often not only acceptable, but frequently downright delicious. As the science of flavor and flavoring foods and beverages unfolds, researchers are discovering new ways to tease and trick the taste buds.

Flavor perception involves a combination of taste (bitter, sweet, salty, acidic and umami), aroma (olfactory input) and chemosensory (cooling and burning) factors; mouthfeel, textures and temperatures; and expectations (perception of a berry flavor may be difficult in a green beverage). All of these may come into play when influencing how the product tastes.

The great flavor coverup One technology that has grown exponentially in the last decade is masking agents. Masking undesirable flavors in food and beverage systems is no easy task. "Masking agents are very application-specific," says Stephen Wolf, director of flavor applications, Robertet Flavors, Piscataway, NJ. "There is no magic bullet when you are trying to mask a flavor or flavors."

Masking agents function as additive ingredients. In other words, "They are added on top of the undesirables," Wolf says. "The undesirables never go away. They remain in the food. Therefore, it is important that the entire food or beverage system be evaluated, including processing and packaging. All of the variables affect the flavor and how the masking agent performs.

"Furthermore, the components of a masking agent can interact with other ingredients in a food system," Wolf continues. "In order for a masking agent to work, product developers must be in partnership with their flavor supplier and have a masking agent developed for the specific application. And, if any variable changes down the road, the effectiveness of the masking agent must be reevaluated." Depending on the scope of the formulation or process change, product designers might find that the original system does not provide the same effect. For example, pH can have a significant effect on the choice of masking agent.

Jeffrey Cousminer, director of savory foods, Firmenich Inc., Princeton, NJ, concurs. "Masking agents are very application-specific. An all-in-one product would mask all flavors in a food system, even desirable ones.

"We have to remember that the mouth is our personal defense system against danger," continues Cousminer. "Many poisonous plants and toxic chemicals, for example, can taste bitter or sour. Masking agents are a scientist's way of tricking Mother Nature into letting you swallow otherwise unpalatable foods. As we all learned from Mary Poppins: A spoonful of sugar helps the medicine go down."

For example, the oil in traditional salad dressings mellows the acidity of vinegar; however, when formulators remove the fat, it amplifies the acid taste. "In this application, one can try to camouflage the acidity to some degree with a sweet flavor," says Cousminer.

Today's nutrition and wellness marketplace is inundated with foods and beverages that have masked flavors. "These products have properties that need to be modified for better consumer acceptance," says Agneta Weisz, vice president flavors and technology, Comax Flavors, Melville, NY. "For example, some artificially sweetened products have an unnatural sweetness profile. We can use flavor ingredients to dampen the initial sweetness perception and others to prolong the sensation of sweetness to make the sweetness appear more similar to sugar."

Many good-for-you ingredients just don't taste that good. The active compounds in many botanicals, for example, consist of glycosides and alkaloids, which are typically bitter-tasting, alkaline substances. Jennette Neske, senior food technologist, International Flavors & Fragrances Inc. (IFF), New York, says, "Some formulation issues that relate to functional foods are masking protein, botanical extracts and bitterness from pharmaceutical actives. Masking the beany, sulfury and earthy off-notes found in soy-protein-based foods is also very challenging."

Masking agents work in different ways depending upon what they are masking and the food application. "Some masking ingredients act as modifiers and others cover the undesired characteristic by providing other sensations or ingredients that compete with specific receptor sites," says Weisz. "Many bitter compounds are close in structure to sweet compounds. Sometimes we can use the sweet analogue of a bitter compound to produce a less-bitter food. Also, by enhancing the saltiness of foods, you can decrease the perception of bitterness. A lot of psychology is involved in the taste perception of foods."

Taste is both psychological and biological. Linguagen Corp., Cranbury, NJ, uses biotechnology to provide solutions to flavor problems. The company's patented bitter-blocker compound, adenosine monophosphate (AMP), inhibits the taste of bitterness by altering human perception.

"Through our understanding of the molecular and biochemical mechanisms of taste, we have been able to discover compounds that act by blocking the perception of the bitter agent," says Robert Margolskee, Linguagen's founder. "Our research is based on the science of taste transduction, which is how the taste cells detect positive, pleasant-tasting nutrients and negative, bitter-tasting compounds. The taste buds on the tongue relay this information to the central nervous system. AMP prevents the negative message from being sent to the brain."

Unmasking a food's identity Masking is the trickiest trick of the flavor trade. Enhancing is much less sensitive, and less application-specific. "Sometimes it can be as simple as adding a bit of oil to a seasoning blend to increase the initial flavor profile," says Jean Bosenbecker, R&D manager for snack foods, Kerry Ingredients, Waukesha, WI.

In a food system, fat can protect and/or solubilize flavor ingredients. Many flavor components are fat-soluble, but they have a range of polarities, which impacts flavor perception. The polar, or charged end, of the molecule is hydrophilic, and dissolves in water, but the uncharged, or nonpolar, section is hydrophobic. Altering the fat content changes the vapor pressures of flavor components, and ultimately, their balance.

Robert Vilim, director of marketing, Importers Service Corporation, Jersey City, NJ, says, "When using flavor oils to make beverages, sometimes it's as simple as choosing the right oil modifier." Beverage manufacturers who use flavor oils make flavor emulsions or clouds that are added into the beverage's water base. Flavor emulsion stability is influenced by factors such as the density differential between the oil and water phases, the flavor oil particle-size distribution, and interactions at the oil-water interfaces.

"Oil modifiers are actually densifiers that adjust the oil so that its specific gravity is closer to one, the specific gravity of water," says Vilim. "The weighted oil is then homogenized with gum acacia to produce a stable emulsion that mixes readily into a beverage. For a dense cloud with good stability, we recommend new NovaRes(TM)1190, a highly functional oil modifier that has GRAS approval. Customers report that our product disperses more readily than some other weighting agents, and produces a cleaner-tasting, more-stable and longer-lasting flavor oil emulsion."

Wolf adds, "Some ingredients act as flavor enhancers by providing a flavor sensation that is weak or even missing from a food system. For example, in nonfat yogurt you might want to add an enhancer that provides the sensation of creamy and rich. That same enhancer might also work in nonfat sauces and salad dressings."

Other enhancers intensify the overall flavor in a food system, playing into what has become the fifth basic taste -- umami. "Literally translated, 'umami' means 'deliciousness' in Japanese," says Matt Hutchinson, manager of research and development, Kikkoman, San Francisco. "It is rapidly becoming recognized in Western culture as the fifth basic taste, alongside sweet, sour, salty and bitter; yet it has long been recognized in Eastern culture as a basic taste. Generally, it is described as meaty, tasty, savory, mouth-filling or mouth-watering, or 'that little extra zing.'

"Umami acts as its own identifiable taste, but affects the other four basic tastes much the same way that we understand how these interact with each other already," continues Hutchinson. "A pinch of salt can suppress bitterness and enhance sweetness. Umami works much the same way, by either enhancing or suppressing the other basic tastes, depending on the relative concentration of each taste."

Monosodium glutamate (MSG) has historically been the ingredient used by formulators to provide umami. The sodium salt of the amino acid glutamic acid, MSG, had fallen under intense scrutiny in the last quarter of the 20th century as a result of its consumption being linked -- yet not proven -- to various ill effects. In 1986, FDA's Advisory Committee on Hypersensitivity to Food Constituents concluded that MSG poses no threat to the general public, but brief, non-life-threatening reactions might occur in some people, and a 1995 Federation of American Societies for Experimental Biology (FASEB) report reaffirmed the safety of MSG when it is consumed at usual levels by the general population, and found no evidence of any connection between MSG and any serious long-term reactions. This report did identify short-term reactions known as MSG Symptom Complex in two groups of people: those who may have a reaction after eating large doses of MSG, particularly on an empty stomach, and people with severe and poorly controlled asthma.

MSG can be particularly useful in the development of reduced-sodium foods, where it not only allows for a lower overall sodium content but can help improve flavor profiles in savory applications. According to the spring 2003 issue of "The Essence of Taste," a newsletter from Ajinomoto Food Ingredients LLC, Paramus, NJ, combining MSG with a small amount of sodium chloride can reduce total sodium in a food by as much as 30% to 40% while maintaining acceptability. MSG only contains about one-third the sodium of salt and is used at much lower levels.

Through the years, researchers have worked to identify natural ways to deliver glutamic acid to foods. "Such enhancers are often based on autolyzed yeast extract (AYE), with different yeast strains producing varying levels of glutamic acid," says Cousminer. "Tomatoes, mushrooms and aged cheese, such as Parmesan, also contain high levels of glutamic acid and can be used to intensify umami in certain food applications."

Hydrolyzed vegetable proteins (HVP) are sometimes used, but they contain salts of free amino acids, such as glutamate, at levels of 5% to 20%, and many product developers approach their use cautiously. HVP is made by hydrolyzing the proteins in wheat or corn gluten or defatted soy flour into amino acids. HVP normally contains 9% to 12% MSG.

Kikkoman recently rolled out an HVP and MSG alternative called NFE-S. Made from fermented wheat protein, NFE-S is produced using specific microorganisms. The resulting product is then spray-dried to yield a powdered flavor enhancer that is high in amino acids, particularly glutamic acid (about 16.5% by dry weight) and short-chain peptides. It can be listed on ingredient statements as fermented wheat protein (wheat protein, salt and maltodextrin).

"NFE-S works synergistically with specific types of AYE that contain high amounts of the 5' nucleotides," Hutchinson says. "Certain AYEs have been autolyzed to break down the peptides into the individual nucleic acids, and can range from 3% to 20%. When MSG or glutamic acid is combined with these nucleotides, the synergistic effect is about four to eight times greater than using either product alone."

Legal flavors at any age It is quite common to obtain flavors through fermentation, especially when those flavors are trying to mimic alcoholic beverages. From bourbon barbecue sauce to vodka marinara, liquor flavors are showing up in all types of nonbeverage applications. Formulators are challenged, however, when it comes to flavoring foods with real, "drinkable" liquor, as the stuff off the shelf is highly regulated.

For example, state regulations limit how much alcohol can be used to formulate packaged foods. The Bureau of Alcohol, Tobacco, and Firearms and Explosives requires special taxes to be paid on alcohol, as well as have food formulas approved.

Because dealing with regulatory agencies can be timely and costly, product developers try to trick consumers into thinking they are tasting "the real thing." This can be accomplished in a variety of ways. However, before a formulator chooses which path to follow, the marketing department must decide what type of language is desired on product labels. Can the pasta sauce be called "vodka-flavored" or should it be flagged as "made with real vodka"?

If "vodka-flavored" or something similar is acceptable, then a flavor extract or concentrate can be used. For example, red-wine flavor can provide an oil-and-vinegar salad dressing with some red-wine flavor and color. Depending on the application, it might be necessary to use a flavor-sensation system that provides the familiar alcohol burn and tingle that somewhat dries the mouth.

Sometimes liquor flavors are used along with ingredients that are very close to the real thing. This means that products can be labeled as being made with the real thing, but a food manufacturer does not need to worry about employees sneaking samples.

"This is because formulators are choosing denatured liquors, which range from wine to malt and bourbon to vodka," says Jim Polansky, national sales manager, Todhunter Foods & Monarch Wine Company, West Palm Beach, FL. Denatured liquors contain ingredients such as garlic, onion or salt, which renders them unsuitable for drinking.

Denatured liquors are also exempt from state and federal taxes, "Yet products have a true spirit flavor and can be described as being made with the real thing," says Ron Call, vice president of research and development at Todhunter. "Denatured spirits are a great labeling tool. Most food products claiming to be made with real liquor are actually made with denatured versions, with denaturation by salt the most common. Product developers simply adjust the salt content of the food formulation to account for the salt in the liquor."

Polansky adds: "We have a brand-new denatured malt ingredient that has applications in beer-flavored condiments. We have also developed a line of denatured flavored rum ingredients, as flavored-rum is becoming increasingly popular in Caribbean and island-style cooking. Denatured liquors are usually used at levels starting as low as 0.25% and going as high as 1.25%, depending on application and how strong you want the flavor to come through. To retain as much flavor as possible, it is best to add the liquor ingredient as late in the process as possible."

Call adds: "Finished products do contain some alcohol, unless they are heat processed; however, the percent is seldom above 0.5%, so no alcohol content declaration is necessary."

If it is important that no alcohol be present, yet authentic flavor is desired, Todhunter offers an exclusive line of reduced liquors, which are 10-fold concentrations of the original liquor. "All the alcohol and a lot of water have been reduced off, and the essence is extremely concentrated and very cost effective," Polansky concludes.

Flavoring liquors and alcoholic beverages is a trend in itself. New Century, KS-based Danisco has developed a line of fruit flavors called Citrus Sensations, which are designed for application in carbonated or still, low- to mid-proof spirit and malt-based drinks. The flavors trick the taste buds into thinking these increasingly popular alcoholic beverages are made with real fruit.

Seasonal flavor and color variation makes using real fruits to flavor liquors and alcoholic beverages challenging. Flavor ingredients remove this obstacle. For example, the dark-red flesh of blood oranges imparts a unique flavor with strawberry and raspberry notes. Flavor extracts ensure a consistent blend of these subtle notes, along with the right level of sweetness and acidity.

Timing is everything Sometimes, when product developers do not want a flavor released in a food until it is consumed, they turn to encapsulation technology. Flavors are typically encapsulated to prevent interactivity with other ingredients, which could produce off-flavors or reduce flavor strength. Encapsulation ensures that the consumer gets a full-flavor taste sensation.

The encapsulating process envelops ingredients, providing a barrier between the core ingredient and the system to which it is added. The barrier must be resilient enough to not be destroyed during processing or through product shelf life. However, it must break down when the food is consumed in order for the person to taste the flavor.

When selecting a barrier material, factors that need consideration include moisture migration, processing temperature and storage environment, which is why most encapsulated flavors are application-specific. Traditionally, encapsulating materials have been water-soluble, preventing their use in high-moisture foods or beverages. Hydrophobic barriers are based on lipids and are relatively new to the world of encapsulation.

Last year, IFF introduced CapLock(TM), a new flavor encapsulation technology that provides flavor quality and stability even after 24 months of storage and "provides improved topnote retention resulting in fresher flavor profiles, compared to traditional encapsulation technologies such as spray drying," says Mike Popplewell, director, delivery systems, IFF R&D. He noted that a stability study comparing the results of an orange flavor using this technology to spray-dried orange revealed that it provides excellent protection to flavor components over time, especially against oxidation.

CapLock provides resistance against moisture absorption during typical handling in food manufacturing facilities, as well as protection against moisture absorption during storage in products such as bagged tea leaves. "It holds up extremely well under humid conditions, which is particularly important for powdered beverage mixes that are popular during the hot summer months," says IFF's Ton Mesters, vice president, global business development, beverages.

Popplewell adds: "We use a proprietary extrusion technology specially designed for the food industry. It retains more of the top notes because the process doesn't remove water. Also it produces denser, larger particles than does spray drying, so there is less opportunity for diffusion."

Recently, Philadelphia-based David Michael & Co. and Balchem Encapsulates, a business segment of Balchem Corporation, Hampton, NY, entered into a strategic alliance to manufacture and market microencapsulated flavors marketed as MichaelCap microencapsulated with Balchem(TM). Balchem's unique encapsulation technology offers a number of attractive benefits as compared to traditional spray-drying of flavors. For example, the flavor load is increased by as much as 100%, while the proprietary coating process provides for a longer shelf life, typically 18 to 24 months. "In applications, the key benefits for food manufacturers in using MichaelCap are sustained flavor release and specific temperature release of flavor in baking or heating," says George Ennis, vice president and chief flavor chemist for David Michael. "In addition, the core flavor is protected from oxidation. More than one flavor can be incorporated into the matrix coating due to the multilayering effect that can be achieved through this advanced technology. The ability to have multiple coatings also helps prevent flavor migration into and out of the finished food product."

Using this technology, the company has developed an artificial butter flavor. "Used at 0.20% to 0.40% in butter cookies, the flavor can be made to be released in the temperature range of 135?F to 155?F, depending on the coating selected," says Ennis. "The economic advantage is that 20% to 25% of the flavor is retained when compared to the liquid counterpart of the MichaelCap flavor. In essence, microencapsulation reduces flavor loss during baking, maintaining critical top notes of the butter flavor. In some applications, MichaelCap flavors can be more cost effective, delivering as much as a 30% savings when compared to a liquid or spray-dried flavor."

A little of this and that Encapsulating is a great trick for dry applications, but currently isn't applicable to fluid products. Here, the trick often isn't in the flavor.

"One of the primary advantages of using gums in aqueous systems is that they do not mask flavors," says Allen Freed, president and CEO, Gum Technology, Tucson. "Formulators are familiar with using starch as a thickening agent, and many choose starch because of its relative low cost. To obtain desired thickness, starches are frequently used at levels of 2% to 6% in product formulations. A disadvantage to this high usage level is the masking of flavors. As a result, developers increase the amount of flavoring to achieve the desired flavor impact. The problem is that the flavoring is now used at a higher level than its ideal usage.

"The advantage to using gums instead of starches is that they are typically used at a very low usage level, such as 0.1% to 0.2%," continues Freed. "When you combine the natural properties of gums, along with their low usage level, formulators can give beverages a great mouthfeel and texture without masking flavor. This enables the flavor to release naturally and exhibit its true profile -- not to mention the cost savings of using less flavorant."

Another way to influence flavor is by harnessing chemosensory responses. Sensation flavors provide foods and beverages with a little something extra. "Cooling flavor enhancers increase the sensation of coldness, providing a longer-lasting taste perception," says Wolf. "Robertet also offers an enhancer that provides the perception of alcohol. It gives low- and no-proof products that desirable bite, burn and tingle."

Kathy Moreau, global marketing manager for sweet at IFF, says, "CoolTek(TM) is a high-intensity cooling technology that imparts a unique taste sensation for a clean, refreshing, energizing taste and feel that invigorates flavor. Although the technology is not mint-derived, it enhances mint flavor systems and is also ideal for nonmint flavor systems. The cooling sensation lasts and builds without a menthol burn, aroma or flavor, and without impacting other flavors in the system."

Another flavor trick involves using fruits such as raisins or dried plums to intensify other flavors in a food system without contributing any characterizing flavor itself. "Raisin paste contributes viscosity and body in addition to eating quality, texture, mouthfeel and flavor depth," says Thomas Payne, spokesperson for the California Raisin Marketing Board, Fresno. "The natural raisin flavor does not interfere or compete with desired flavor profiles. Rather, the inclusion of raisins augments the flavor of other ingredients, adding a well-rounded, fresh note. In fact, a naturally occurring organic acid in the grape called tartaric acid helps enhance flavors, making spices and ingredients sparkle."

James Degan, a consultant with the Sacramento-based California Dried Plum Board, says: "Dried plums contain about 2% naturally occurring malic acid, which has been shown to be an effective flavor enhancer. Malic acid is released more slowly than other organic acids, and thus has a greater carry-through during the chewing process.

"Dried plums have also been shown to have the highest total antioxidant power among the most commonly eaten fruits and vegetables," adds Degan. This antioxidant activity has been linked to the reduction of lipid oxidation and warmed-over flavor.

From blocking taste receptors to adding noncharacterizing flavors, researchers continue to actively pursue different ways to tease and trick consumers' taste buds. As long as food manufacturers continue to innovate, flavorists will keep performing tricks.

Donna Berry, president of Chicago-based Dairy & Food Communications, Inc., a network of professionals in business-to-business technical and trade communications, has been writing about product development and marketing for 9 years. Prior to that, she worked for Kraft Foods in the natural-cheese division. She has a B.S. in food science from the University of Illinois in Urbana-Champaign. She can be reached at [email protected] .

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