Flavor Tricks

Food Product Design

Flavor Tricks

December 1999 -- Design Elements

By: Paula Frank
Technical Editor

  The term "flavor tricks" brings several things to mind. The idea can be as simple as combining two peanut butter and two grape Jelly Belly® jelly beans to make a peanut butter and jelly sandwich, as suggested by the product's manufacturer, Herman Goelitz Candy Co., Fairfield, CA. Or perhaps the vision of a poached pear in raspberry sauce comes to mind as you chew simultaneously on juicy pear and raspberry varieties. All right, maybe these concepts are in fact flavor tricks, but it usually gets a little more complicated than that for today's flavor chemists and food technologists.

  You may wonder why a flavor supplier has at least 200 different chicken flavors, or equally as many strawberry flavors in their portfolio. "Our development is so heavily laid on what the application is," says Mary Maile, senior flavor chemist at Innova, a Griffith Laboratories Company, Oak Brook, IL. "People don't realize that," says Yogi Desai, manager of flavor technology at the company. "Flavors are so application-specific. The most important thing for a flavor chemist to learn is sound applications and processing knowledge." That's why it is so critical to give detailed information, including ingredient and labeling requirements, process parameters, and distribution and storage conditions, when requesting flavor samples.

  Flavor chemists are well-versed in providing a variety of products that contribute unique properties to a base. These properties, which are derived from different techniques, include flavor contribution, balancing, enhancing, masking and timing of flavor release. Although some of these tricks of the trade are proprietary, others provide valuable insight into flavor delivery.

Blowing off steam

  Balancing flavor in a system can be a tricky proposition. "From a flavorist's point of view, when a flavor is peaky or out of balance, it has been formulated using materials that have different volatilities, with holes left in the middle where there are no chemicals to kick in," says Dennis Kucharczyk, master flavor chemist at McCormick Flavors, Hunt Valley, MD. "So basically, if you used esters or acetaldehyde or some chemicals that are extremely volatile, they would come up front in the flavor profile. If the only other thing you had in the flavor was ethyl vanillin or ethyl maltol, those are nonvolatile, so they would come very late in the profile. With just those things in your flavor, you would get a very early hit and a very late hit, but you wouldn't get anything in the middle.

  "So it's the job of the flavorist to try and make sure that he uses raw materials that bridge the whole gap of volatility to get rid of the 'peakiness,'" Kucharczyk continues. When appropriate, he says, a class of compounds called lactones can balance the flavor and get rid of the peakiness; however, usage is up to the discretion of the flavorist.

  Flavors are delivered to formulations in liquid or dry form. Liquid flavor has been incorporated into an oil-soluble or water-soluble matrix. Soybean oil typically acts as the oil-soluble carrier, while ethanol, propylene glycol and glycerine are used for water-soluble fluids.

  Oil-soluble flavor molecules dispersed into a water-soluble carrier can be made into an emulsion. Although the base is water soluble, the emulsion can break. This is evidenced in still beverages where a ring of flavor forms at the beverage surface. Carriers must be chosen with the process in mind. "In general, oil-soluble flavors tend to be more heat stable," says Kucharczyk. "Water-soluble flavors, especially if alcohol is one of the primary solvents, will tend to be less heat stable, mostly because they are more volatile than the oil. The oil is less volatile, so it tends to retain flavor better."

  Volatility helps determine the type of flavor carrier. "If you put 50 different aroma chemicals or natural flavor extracts into a flavor composition, some of them have boiling points of 120°F, 140°F or 160°F," says Anton Angelich, vice president of the sweet business unit at Haarmann & Reimer, Teterboro, NJ. "When processing this flavor in an open kettle at 130°F, you are going to lose all the lower-temperature volatile notes. Then it's not going to be the composition of 50 compounds that the creative flavorist put together, because many will be lost. You'll end up with half a strawberry, or half an apple with maybe the skin notes missing, or the seedy notes missing. So, the flavorist has to worry about using the right carrier-protective system to protect the volatilization of the aroma chemicals."

  Both volatile as well as nonvolatile components are needed in a flavor, because, when tasting food, the perception of the flavor affects the smell and the taste, notes Desai. Often, a dried spice - which has both volatile and nonvolatile fractions - will be sufficient in an application. However, where initial aroma impact is critical, a more volatile form is needed. Maile explains, using sage as an example: "Sage is very volatile. It also has some nice meaty, woody notes." That's why two sources of sage, such as an oleoresin and a dried spice, may be helpful. "If you put them into soup, you want to get the aromatics once it hits the heat, but you also want that flavor of the sage from within the soup," continues Maile.

Singing in harmony
  Balance is not only achieved by managing volatility, but by working with the base. The inherent flavor strength and composition of the base dictates its compatibility with a particular flavor or flavoring ingredient. "Flavors often are one thing when looked at in the absolute, but when they are combined in any kind of application base or matrix, you then have the taste elements of the base or the matrix that combines with the flavor," says Angelich. For instance, bitterness is not naturally significant or inherent in grape flavor. When putting grape flavor into a pharmaceutical product with an active bitter component, the result is something that is bitter and doesn't taste like grape. Instead, select a flavor with a bitter profile; the bitterness can then be removed by the flavorist and supplied by the active material in the base.

  All products in nature are defined by certain inherent elements. Angelich points to fruits such as cherry or strawberry, which have not only characteristic flavor, but also a natural sweetness and an acidic element. Acidity and sweetness wouldn't come from a fruit flavor, but from the base. "If you have a product that doesn't have the sweetness, it's not going to taste like strawberry. If the acid isn't there, it's not going to taste like strawberry. Acid, Brix and flavor are three elements to fruit flavors; it's like a three-legged stool. You need all three to make it balance," he says. So it is critical to link all the elements of a product when you create a particular taste.

  In the previous example, the base might not provide the needed acidity. If so, another, more compatible flavor should be chosen. "Perhaps something like chocolate," says Angelich. "Chocolate is a real hard one to deliver, because everyone wants to put chocolate flavor in things like yogurt or coffee or something that has acidity to it. By throwing off the pH, you end up with something that isn't chocolate as the consumer knows it. Chocolate is defined by consumer expectation as being an alkaline product. So, it's an interesting thing to balance both the pH and the sweetness."

  Vanilla can complement chocolate's sweetness, but one particular type of vanilla will often work better than another, notes Craig Nielsen, vice president, Nielsen-Massey Vanillas Inc., Waukegan, IL. Straight Indonesian vanilla performs better than straight Bourbon, because chocolate is very sweet and Bourbon vanilla's sweetness and creaminess get lost. Indonesian vanilla complements chocolate better because it has components that are similar to the pyrazine (roast) character of chocolate. "Vanilla is a very application-driven product. Just because Madagascar is considered to be the highest quality, doesn't mean that it works best in all applications. Always know the geographic source of your vanilla," says Nielsen, adding that the optimal contribution of vanilla in an application may require blending different varieties of vanilla - which is something that suppliers should be able to do without added cost.

  The selection of food acids is driven by various criteria, including cost and flavor compatibility with the application. Using acids that are intrinsic to the targeted flavor can provide synergy. For example, at Flavor 101®, a technical training course conducted by Flavors of North America, Inc. (FONA), Carol Stream, IL, the class sampled two samples of a grape still beverage containing citric acid and tartaric acid. Although citric acid is more widely used because of its lower cost, tartaric acid actually complements this beverage better, because it occurs naturally in grapes. Tartaric acid also complements a Worcestershire sauce-type flavor, says Desai, because it is inherent in tamarind extract, an ingredient that flavors the sauce and gives it an acid bite.

  Sometimes the natural flavor properties of a base allow for a reduction in an ingredient. Mike Augustine, director of food ingredient applications at A. E. Staley Manufacturing Company, Decatur, IL, cites certain instances where maltose partially replaces sucrose in cakes. Although maltose has a relative sweetness of 33 compared to sucrose's relative sweetness of 100, you don't notice any difference because of the natural sweetness of the bakery product. An extended shelf life is one of the benefits afforded by the reduction in sucrose solids.

  Thus, flavor balance can be achieved in a variety of ways to promote synergy within a product. Once the ingredients are selected based on flavor compatibility, processing, storage and shelf-life conditions must be considered.

Don't stress 'em out

  In addition to using chemicals and ingredients that will not volatilize during heating, a flavorist might also adjust his or her levels to achieve the desired flavor balance. A tomato-basil flavor developed for a snack application would require adjustment for a chicken application, because some of the more delicate tomato notes would diminish during heating, causing the overall flavor to seem unbalanced. To achieve a balanced flavor, with tomato notes up front and basil notes in the background, the flavor chemist will have to increase the tomato, and possibly reduce the basil. "You have to create a balance between the desirable up-front versus the background notes," explains Desai.

  High heat can be detrimental to a flavor such as vanilla. The developer can achieve a successful outcome by choosing the right type of vanilla as dictated by the application. Madagascar Bourbon vanilla works better in a cake with a high mass and volume, because the internal temperature doesn't rise quickly. The internal temperature of a cookie, however, heats up very quickly, because of the cookie's low-mass, low-volume structure. Indonesian vanilla is preferred for this type of process because, although it is a bit harsher than a Bourbon type, it "holds up to heat better and actually mellows out during the cooking process," explains Nielsen. Thus, ingredient selection, including form and origin, impacts finished-product quality.

  Harsh processing conditions can be detrimental to flavors, but so can storage conditions or the presence of live cultures. "Some systems are very, very dynamic, like yogurt with live cultures that keeps changing. Everyday it evolves and becomes another product," says Angelich. In this case, you have to look at how much flavor you are putting in, and how the flavor delivers perception at every stage of the shelf life of the product; you might have to make trade-offs, he says. "Maybe initially you have to put it in at an unpalatably high level, but in the first seven days, from the time the yogurt and flavor come together, no consumer will taste it. It's going to take seven days to get from the production floor to your distribution center. So, at that point if the flavor level is too high, that's OK. From day seven to day 31, if it's fine, that's great. And by day 31, if it isn't too acid and the flavor isn't too low, then you are OK.

  "People in the yogurt business do a lot of sensory work and look at the shelf life very carefully," continues Angelich. "But a product development person entering that arena has to be very cognizant of this, and very cautious to make sure they don't develop the perfect product for day one, and then seven days later, it has turned into something else that is unacceptable, weak, or not competitively good."

  Avoiding flavor loss over the course of shelf life can be addressed by overcompensating up front. The level of mint flavor used in chocolate mints is so high initially that it would "knock you over," Angelich says. This is because the overall taste perception weakens as the flavor is absorbed into the chocolate's fat. Shelf-life length must be known in order to pinpoint the time when taste is at its optimum. Accelerated shelf-life studies can help determine the appropriate flavor level in this particular application.

Making a lasting impression

  One way to refine a flavor profile is by adjusting its duration. Using nonvolatile vs. volatile components, food acids, and less-enhanced vs. more-enhanced ingredients can affect this. An ingredient such as capsicum used at a below-threshold level can affect flavor duration. "It helps anything linger more, keeps it in your mouth, again using your taste factors. You don't want it to stick out, but you just want to leave that sensation of (lingering)," notes Maile. Other factors, such as fat content and viscosity, influence the length of the flavor profile as well.

  Different processing techniques result in flavors that can withstand certain adverse conditions. As a result, flavors are released at select times throughout the shelf life of the product, depending on the circumstance that causes its release. These techniques influencing flavor duration are valuable development tools that enable developers to put a unique spin on their creation.

  Topnoting a flavor can produce initial impact by means of volatility. Flavorists intentionally incorporate low-boilers into a flavor profile to give it lift, notes Carol Militescu, senior flavor chemist, FONA. Kucharczyk describes another industry definition of topnoting, where a flavor chemist adds flavor chemicals on top of a generic, nondescript flavor or a key to give it more definitive character notes. The nondescript meat flavor then becomes more beefy or chickeny or roasted as a result.

  Flavor chemists can analyze a product with GC/MS to determine which chemical compounds a flavor contains. According to Jane Hohn, vice president savory flavors, Bush Boake Allen (BBA), Montvale, NJ, this information is then used by flavor chemists in the creation of new flavors.

  Yeast extracts, hydrolyzed vegetable protein (HVP), disodium inosinate and disodium guanylate (I+G), and, of course, monosodium glutamate (MSG), have been used for years as flavor enhancers. More recently, yeast extracts high in glutamic acid, as well as 5¢-inosinate (IMP) and disodium 5¢-guanylate (GMP), are growing in popularity. Not only do yeast extracts enhance flavor profiles, but they lengthen the duration as well, says Richard Calk, president, DSM Food Specialties, King of Prussia, PA. A fermented soy flour was recently introduced to the market and is specifically designed to increase flavor duration. The term "linger longer" has actually been trademarked to identify this product, adds Calk.

  We've all witnessed the recent trend shift from no-fat to lowfat products. Apparently, many consumers have decided that they prefer flavorful food with a little fat to products that lack both fat and flavor. Fat coats the mouth and helps flavors last longer. Flavors in nonfat products tend to dissipate very quickly.

  Product viscosity affects not only flavor duration, but also intensity. The higher the viscosity, the lower the flavor intensity, because the flavor won't release as quickly, but it will last longer. Flavor in a beverage with no body might have a strong initial impact, but "it hits and is gone," notes Sara Risch, Ph.D., participating faculty member of Flavor 101 and principal, Science by Design, Chicago. Flavors will be carried differently in products of different viscosities. The relative sweetness of 55% solids fructose is 99 compared to that of sucrose at 100, yet when flavors are tasted in 77% solids fructose syrup and a sucrose solution of equal solids, the flavors in the fructose syrup won't come through, because the more viscous syrup has an overpowering sweetness to it, notes Augustine.

  The decision to make a flavor water soluble or oil soluble is based on potential volatility as well as ease of dispersion in a matrix. However, many product developers prefer to work with dry flavors for one reason or another. Dry flavors can be processed in a variety of ways. Encapsulating liquid flavors provides many benefits, including greater stability, extended shelf life, and more control over flavor delivery.

  One method of encapsulation is spray-drying, which some consider to be more of an entrapment process. Gums, starches and maltodextrins are the most commonly used encapsulates for spray-drying. While some prefer gum's performance, Maile points to research suggesting that the combination of starch and gum produces flavors with superior shelf life and stability.

  Other encapsulation processes give a coating that requires either heat or mechanical stress to release the flavor. A product produced by coacervation requires physical stress, such as chewing, to release the flavor. Scratch n' Sniff® surfaces, like those used in advertising, use this type of technology, says Risch. For foods, fluidized-bed coating covers a spray-dried product with a high-melt fat and releases flavor when exposed to heat.

  Another form of encapsulation that protects flavor from heat is one that many of us have incorporated into our baking process at home. Nielsen explains that blending vanilla in fat prior to baking gives the flavor a protective coating. The flavor is eventually released into the matrix as the fat melts during heating.

Razzle dazzle 'em

  As tastes change with shifting demographics, new and extraordinary methods of flavor enhancement come into being. While traditional enhancers are still widely used, other products are becoming more prevalent, partially due to consumer demand for more natural, cleaner labels. Angelich cites the maturing population's waning ability to discriminate aromas due to widespread use of medications as one reason to add pizzazz to food. In addition, he points to increased cultural diversity and ethnicity. All of these factors bring spicier, more pungent, nontraditional foods to the table. Today's cuisine is becoming spicier, with enhanced perception of the classic tastes of salty, sour, sweet and bitter.

  Adding the perception of saltiness to a product without actually adding salt is the goal of many product developers. Naturally brewed soy sauce not only enhances overall flavor, but enhances salt perception as well. "You can use soy sauce and decrease your sodium," says David Foster, R&D manager, Kikkoman Marketing and Planning, Elgin, IL. "People might think, 'well, I'm not going to put soy sauce in, because soy sauce is too salty, and I need to decrease my salt.' But soy sauce can actually help in that regard."

  Soy sauce also works well as a general flavor enhancer. It's a product of fermentation that contains 300 flavor compounds, including salt, glutamic acid, lactic acid, alcohol and esters. According to Foster the synergistic relationship between glutamic acid and the other flavor compounds makes soy sauce an exceptional enhancer. Although soy sauce is generally thought of as a flavoring agent or enhancer of savory products, it can also be added to chocolate to enhance the nutty character or to ice cream to enhance flavor.

  A high level of 5¢-nucleotides functions similarly to soy sauce by enabling reduced salt levels without losing the perception of salt. Other ingredients can give the perception of saltiness, such as spices, herbs, and vegetable flavors such as garlic and onion. Herbs such as thyme and sage used at threshold for enhancement, or above threshold for flavor and enhancement, heighten the flavor perception in savory dishes, notes Desai. Using wine powders in tomato products is yet another nontradtional method to increase the perception of saltiness, adds Ken Burkhard, vice president of sales at Haarmann & Reimer.

  Sour and bitter notes, while not always desirable, are sometimes necessary to define a particular product's character. Specific chemicals such as quinine can provide bitterness. Botanicals such as fenugreek, senna, chicory root, coffee and dandelion also give bitter notes, especially when natural ingredients are desired. Brewer's yeast, which picks up a bitter residue from the brewing process, can also enhance this type of character. According to Calk, "brewer's yeast extracts are normally thought of as being dark and bitter, and are used in beef-type formulations. We found a lot of success using those in cheese applications, where they normally weren't thought of. What they actually add are the aged notes to the cheese, so it allows the product formulator to buy, for example, a three-month old Cheddar, and make it taste like a nine-month old Cheddar."

  Calk recommends using a high level of 5´-nucleotides to enhance sourness. Sour character is most often derived from food acids. However, these acids deliver other flavor qualities as well. Citric acid hits in the front of the mouth, while malic hits in the back. These properties were demonstrated in an experiment conducted at Flavor 101 - three variables of a strawberry still beverage were sampled, containing equivalent levels of citric acid, malic acid and a 50:50 mixture of both acids. The sample with malic acid seemed intensely sweet because the sweetness hit before the acid. The 50:50 mixture seemed to carry the flavor more readily. T. Leslie Fisher, vice president of technical marketing at FONA, cited instances where organic acids can give high-impact to flavors. For example, a high percentage of acetic acid is used for certain brands of candy, especially grape bubblegum, to produce the sour notes or the high-impact tart notes.

  Sweetness can be enhanced in a variety of ways, depending on the application. Sugar can enhance, and then overpower, a flavor, because sugar's sweetness actually competes with the flavor. Combining fructose and sucrose can give a higher relative sweetness in certain beverages, which allows for the reduction of sweetener solids. Maltol and ethyl maltol, products of the Maillard reaction, are often used to enhance sweetness in low-sugar products and baked goods that aren't exposed to extended baking times that traditionally generate sweet-brown notes.

  Other products not ordinarily thought of as sweeteners enhance this type of character also. Yeast extracts contribute brown, sweet-type flavors in products such as vanillas, caramels and chocolates, says Calk, who also notes that fermented soy flour enhances the sweet notes of vegetables such as carrots and celery. Vanilla acts as a natural sweetener to not only baked goods, but salad dressings, seafood marinades, and fruits. In fact, Bourbon vanilla or a blend of Bourbon and Tahitian vanillas enhances the natural sweetness of fruit, and can make up for the use of poorer quality fruit, says Nielsen.

Out of sight

  Sometimes flavors mask objectionable off-notes, and yet circumstances arise where knowing how to prevent flavors from being masked by other ingredients is crucial. Sometimes masking flavors have to neutralize the base of a product to get an incompatible flavor to work. Burkhard recalls adding a cherry flavor to a pharmaceutical product that was very bitter. None of the cherry flavors tried met with success, but a banana flavor worked very well. Benzaldehyde (an identifying compound of cherry) was added on top of the banana flavor, which gave the product the aroma of cherries with the flavor of bananas. Burkhard cautions that pharmaceuticals need to be palatable, but not gourmet. You don't want consumers, especially children, abusing these products because they taste too good.

  Sweeteners can mask other tastes. Since citric acid and fructose come on strong initially, they tend to compete with one another. A different acid such as malic, will allow for a more balanced sweetness-acidity profile, because it builds more slowly; therefore, the sweetness will hit up front, followed by a hit of acid. The goal is to achieve balance among all flavoring components, so that flavors peak at different times.

  Fat has a tendency to mask certain flavors. This situation occurs with vanilla in high-fat ice cream. According to Nielsen, this can be avoided by using the proper type of vanilla. A blend of Indonesian and Bourbon vanillas is the best choice for high-fat ice cream. Indonesian vanilla helps cut through the initial fat-masking and the Bourbon carries through the entire flavor profile.

  "Replacements, maskers or enhancers have to be custom work in order for it to be efficacious. You have to find the right combination of ingredients to get the effect you're after," says Fisher.

Nouveau rich

  Feeling factors such as creaminess and richness are important attributes. Fat is the principal component that drives these factors, so when fat is either reduced or removed, the product developer must replace these sensations with other alternatives. Combining vanilla extract with enzyme-modified dairy products adds richness to a product without adding fat. The vanilla mellows out the background notes, explains Jim Raugh, director of vanilla development at BBA. The enzyme-modified dairy products give the taste sensation and intensity, but not the texture. "The trick is to get the right balance of free fatty acids," says Peter Freund, director of dairy development at BBA. Cheesy flavor notes will be produced if the level of enzyme-modified ingredients is too high, and bitter or soapy flavor notes may also result if the proportion of long-chain free fatty acids is too high.

  "All enzyme-modified creams and butter fats are not alike," says Freund. "It depends upon the quality (and processing) of ingredients." Raugh and Freund describe two examples of the functionality of vanilla in combination with enzyme-modified dairy ingredients. In one application, vanilla extract is combined with nonfat dry milk to simulate 2% milk. By adding 0.25% enzyme-modified cream to skim milk, the total fat in the system is increased by merely 0.10%. The other application incorporates vanilla extract with 0.10% cooked-cream flavor and 0.20% enzyme-modified cream to produce a vanilla sherbet. Again, additional fat is 0.10%. Ordinarily, vanilla extract would not work well in sherbet, because of the low fat content.

  Fermented soy flour also contributes to the sensation of creaminess and richness in lowfat dairy products such as ice cream and margarine, as well as lowfat vegetable spreads, adds Calk.

  Lowfat foods can also be supplemented with fat flavors in combination with food acids. "Food acids have that special mouthfeel of fat called succulence," says Desai. A lowfat dairy system could support a combination of lactic acid with a butterfat or other dairy-derived fat flavor. Lactic acid would be the most appropriate choice in this scenario, because it's a natural derivative of dairy fermentation.

Fool's gold

  In today's world of food processing, things aren't always as they seem.

  Just because the piece of chicken you ordered tastes like it was grilled on the barbecue doesn't mean that it was. Cooked flavors such as grill and smoke give the impression that a cooking process imparted the flavor, as opposed to an ingredient. Roasted flavors, such as those associated with garlic, other vegetables and meats, are derived from flavor reactions. According to Foster, soy sauce can produce these types of roasted flavors in many of these reactions. Yeast extract is also a good source for reaction flavors, when browning and roasted characters are desired, adds Calk.

  Colors can trick the senses into believing that they impart specific flavors, when in fact they deliver something else. Reacted yeast extracts not only deliver roasted character, but can function as a caramel-color replacer as well. When we consume a green-colored beverage, we expect the flavor to be either kiwi or lime, but what if it was actually flavored with grape? Most people would find it difficult to discern the grape flavor. Sometimes, colors attract certain segments of the population. Kids went wild over an ice cream product called Dinosaur Blood that was a blend of five different vibrant colors, says Bill Pullia, director of flavor applications at FONA. Yet, the ice cream was vanilla-flavored.

  Interestingly, the growth in vegetarian entrees has resulted in a reversion to traditional Maillard-reaction products, although the protein source that is hydrolyzed into amino acids comes from nonmeat sources such as vegetables, autolyzed yeast extracts and HVPs, notes Hohn. These nonmeat-based reaction flavors give vegetarians the opportunity to eat meat-flavored items such as a grain-based patty that tastes like a hamburger. Initially Desai jokes about these flavors: "Why do you want to eat meat if you are a vegetarian to begin with? Why do you want to taste something like beef? If you want to eat beef, eat beef," he says. Yet, he concludes by discussing the value of using vegetarian meat flavors in developing products under halal guidelines, because halal-certified meat products are difficult to source in the United States. Besides, flavor tricks or no flavor tricks, those of us who like to watch our calories once in a while go for the veggie burgers too, hoping they'll taste just like those burgers we remember from our thinner days.

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