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September 1, 1999

27 Min Read
Bar Talk

Food Product Design

Bar Talk
September 1999 -- Design Elements

By: Lisa Kobs
Contributing Editor

  Whether you're looking for an energy blast before a workout, a weight-loss tool, an after-school snack or an on-the-go meal, the snack-bar industry has a product for you. By 1996, the snack bar market had already reached $20 billion, and it's still growing. To help ensure further growth, manufacturers continue to ask the all-important questions: What do consumers want in a cereal bar? Are bars tasty snacks eaten for pleasure, as a nutritional supplement, an edible medicinal panacea, or something in between?   Snack bars fall loosely into two categories - grains held together in a syrup matrix, of which granola bars are a well-known example, and grains baked in a chemically leavened dough.   Some snack bars have undergone a complete nutritional makeover - the resulting energy bar is the most significant development the snack-bar category has ever seen. Targeting health-conscious consumers concerned with meeting daily nutritional needs has become good business, as illustrated by the 1997 market of $55 million in this category. With names such as rocky road, peanut butter crunch, and chocolate chip cookie, these bars are positioned as a delicious, balanced and concentrated food source rather than just a granola-covered vitamin pill.   The technologies and ingredients required for each of these bars share some similarities, but the designs for each type have some distinct differences. Great granola  Granola-style bars evolved as a convenient way to consume the mixture of cereal grains and other ingredients known as granola. The term "granola" is open to interpretation, but according to Bill Bonner, director of technical services for ConAgra Specialty Grain Products, Omaha, NE, granola bars start with either raw oats or granola cereal. "It's probably best to make granola cereal before making the bar, because it helps to get better textural definition of the grains as the cereal is separated by a binding matrix."   Granola bars are manufactured by mixing the granola cereal and other dry ingredients with a binding syrup. Oats have become the standard grain in granola, because of their low cost. The rolled oats and other grains go into a coating drum and a premixed, heated sweetener syrup is sprayed on top of the dry grain.   "Inclusions, such as fruit or candy bits, are added last so they see little process contact time, keeping them as intact as possible," says Bonner. "The binding syrup still has some heat at this point, so it is important not to melt them. Another important factor in working with inclusions is the design of the mixer, including the number of paddles, the angle at which they are set and the speed of the mixer." After tumbling, the mixture is dried down to less than 5% moisture in a drying bed or baking oven.   Granola bars might be soft and chewy, or crisp. "Soft and chewy bars are basically just dried, so it helps to think of these as using more of a confectionery-like process rather than a baking process, whereas the crisp and crunchy variety is formulated to be baked like cookies," Bonner says. "The sticky mass makes machinability a major issue, he notes. "The binding syrup formulation is a critical factor and should be designed with efficient manufacturing in mind. Adding a small amount of oil or adding a surfactant ingredient such as lecithin, especially with fat-free products, will aid machineability. Building in dwell time on the floor, by modifying the ratios of the sweeteners, can reduce product waste by accommodating for the length of processing time or any unforeseen down time." Filling a need  Filled cereal bars are the second type of bar in the grab-and-go snack-bar category. These bars are typically characterized by a thick, fruit-flavored paste surrounded by a soft, cake-like cookie dough containing varying levels of grains.   While all products have their formulation and processing secrets, Brian Strauss, head of experimental baking at the American Institute of Baking, Manhattan, KS, explains some general similarities that apply to the manufacturing of these bars. "The first stage is mixing; that is typically done in a horizontal mixer with a sigma bar configuration. The sigma blade contributes good blending of the ingredients in the shortest amount of time with the least amount of energy going into the dough. It is important to just incorporate the ingredients together rather than work it like a bread dough."   The equipment choices for making filled cereal bars vary. Typically, manufacturers use a two- or four-roll extruder (similar to a wire-cut machine) or a Rheon machine specifically designed for this type of product. They extrude the dough at the same time a filling is extruded into its center. "If the bar is to have sealed edges, a process called cold cutting, using a blunt knife, crimps and seals the edge of the dough around the filling portion before the product is baked," says Strauss. "Bars with open ends are typically cut after the baking process to prevent problems with filling boil-out." Baking typically requires a continuous-band oven.   "The water activity is an important factor in regard to the interaction between filling and crust," notes Strauss. "The aw of the filling has to be compatible with the dough component to promote moisture transfer into the cookie crust after baking, to make it more soft and palatable. The aw of the filling must be low enough to lower the boiling point to prevent boil-out during the baking cycle, and to prevent it from making its own steam which will then crack the dough during the baking process." Strauss recommends that the aw of a equilibrated bar be around 0.70 to 0.75. "While water activity of the two components can be measured during formulation, it is the equilibrated water activity that is of real importance and this can only be assessed with time."   Although the dough for filled cereal bars is similar to that of cookies, it takes on cake-like characteristics. It has a higher moisture than cookie dough, and is mixed slightly longer than a wire-cut or rotary-molded dough. The dough needs to be pliable so that it can be formed without cracking or breaking. It also requires some strength, because of the extrusion process. Ingredients must be evenly distributed in the dough to prevent uneven dough-wall thickness.   Soft wheat flour, with a protein content around 9.0% to 9.5%, is used for most bars. A more chunky style also contains whole or coarse grains or bran. Says Strauss, "The biggest impact these added grains have is their water-absorbing characteristics. The more high-water-absorbing ingredients, the more water is needed for the dough. Trying to compensate for water-absorbing grains may alter water activity and lead to a very sticky dough. Large-particle grains can be problematic because they interrupt the dough matrix. They also can lead to problems with the dough extrusion by clogging up or getting caught up on the end of the extruder nozzle."   In other ways, filled bars require many of the same technologies as a typical cookie dough. Sweeteners commonly used include sucrose, liquid sugar, corn syrup, invert sugar or a combination of these. These provide a sweetness while modifying water activity. There must be enough liquid sugar to obtain the desired humectancy without making the dough too sticky to process. The higher the liquid sugar level, the more sticky the dough will be.   Fat in this type of bar is typically a partially hydrogenated vegetable shortening. Emulsifiers such as mono- and diglycerides, DATEMs and lecithin help retain air and leavening gases, promote even, tender crumb structure, modify dough texture and assist with band release. Hydrocolloids and specialty starches manage moisture as the bar equilibrates, contributing to tenderness and mouthfeel.   A leavening system compatible with the processing method must be selected to obtain the desired volume and cell structure. Leavening systems typically work best in combination. A fast-acting leavening acid will establish air cells and a nucleation size that is expanded by the gas liberated in the later phase of the process. This leads to a more even texture and a more controlled product. Sweeteners will also impact leavening. Granular sweeteners promote better leavening due to air bubbles trapped in the fat surrounding the particles of sweetener during the creaming stage. Released carbon dioxide and steam fill these bubbles, promoting a finer crumb structure.   Ultimately, the dough system requires a lot of trial and error. Matching the flow characteristics of the filling with that of the dough so that they move together to form an evenly filled bar is important, as is achieving the required water activity for finished-product quality and acceptability. The good news is that various avenues of assistance are available to the food developer, including short courses and technical assistance from organizations such as The American Institute of Baking, which can help resolve many formulation issues. Energy bars  Energy bars provide protein, complex carbohydrates, fiber, good-for-you fats, health-specific vitamins and minerals, and even phytochemicals. An energy bar can be any style - a granola or baked-and-filled variety, or a smooth and creamy bar resembling a confectionery product.   In the past, energy bars lacked pleasing flavors and textures. Fortification-related flavor issues caused some difficulty, as did the texture problems caused by excessive density (some products required vice-like jaws to consume). Today, many of these technical glitches have been worked out, resulting in a much more palatable bar.   The nutritional make-up varies in the ratio of fats, carbohydrates and proteins. Lately, high-protein, low-carbohydrate diets have received much publicity, so bars have followed suit. But there is still a market for nearly every combination of nutrients and caloric levels. Chocolate BarsAlmost everything tastes better dipped in chocolate, and even a thin layer of creamy coating adds value, eye appeal and flavor to a bar - though its health-food status may come into question. Various coating options are available and some are strictly defined: Dark chocolate must contain no less than 35% by weight of chocolate liquor, and consists of sugar, chocolate liquor and cocoa butter with vanilla optional. Milk chocolate must contain no less than 10% by weight of chocolate liquor and no less than 12% by weight of milk solids. It also consists of sugar, chocolate liquor and cocoa butter with vanilla optional. "Chocolate must be solely made with cocoa butter, and to date, it is not permissible for U.S. manufacturers to use any vegetable fat in chocolate," says Irene Yang, research and development project scientist with the Guittard Chocolate Company, San Francisco. White chocolate does not contain any chocolate liquor, and therefore it is not actually chocolate. It is typically a blend of cocoa butter, dairy ingredients, sugar and flavorings. Compound coatings are a class of products made with hard vegetable fats, other than cocoa butter, that have a wide range of melt points. Other ingredients include cocoa, sugar and flavoring. "Hydrogenation of vegetable oils is important to impart the desired stability and functional properties needed," says Yang. "Compounds incorporate fats that will attempt to mimic cocoa butter and act like chocolate. Compounds are never blended with chocolate because cocoa butter is not compatible with most of the vegetable oils, and would lead to an unacceptable product that was fluid and would not temper or hold its shape properly." Yogurt coatings are compound coatings containing yogurt powder and/or other dairy products and hydrogenated vegetable shortening instead of cocoa butter. Carob coatings are also compounds, using carob rather than cocoa. Carob contains less than 1% fat; however, the coating is made through the addition of hydrogenated vegetable oil and sugar. Yang suggests evaluating the following factors when considering a coating: Chocolate vs. compound. Compound is easier to handle, is more forgiving, and does not require tempering. The flavor of a good compound can rival that of a mediocre chocolate. Chocolate allows for a clean ingredient label. Economics: Chocolate costs more than compounds. The coating should be selected based on the target market. Some more affordable chocolate products and better compounded products have an acceptable quality. Application: What are the desired finished characteristics, and the manufacturing and processing capabilities encountered? Get the exact handling instructions from the manufacturer for best results. Cereal grains  No matter what the style, the defining ingredient in a cereal bar is the grain. Grain kernels are usually divided into three layers. Structurally, the kernel consists of the nutritionally dense pericarp (or bran), germ and endosperm.   Processing may be limited to removing the hull and leaving the whole grain, but other processes can separate out the different fractions and reduce particle size. Grains can be processed leaving varying degrees of the bran, germ and endosperm. Wheat loses its hull during the cleaning and separation step, so it is handled as a naked grain. The pericarp in wheat is removed after a conditioning step, followed by rolling and sifting. Grains such as rice and pearled barley have a tightly attached pericarp, and removal requires abrasion. Grains processed in this manner still have the germ attached, which makes them subject to rancidity. The remaining endosperm can be left in one piece, broken into pieces called grits, ground into meal or flour, or made into a puff or flake. A grain's bran portion can be stabilized and used to increase insoluble fiber levels and contribute protein, fat, vitamins and minerals.   Product texture can be varied not only with the type of grain selected, but also the form. Combining grits or flakes with crisped grains can create a light texture and tender product. The particle size affects how a grain performs, as well as the finished bar texture. "The oat kernel is soft, so product texture will be softer," explains Gary Fulcher, professor of food science at the University of Minnesota, St.Paul. "The size and thickness of the oat flake impacts the visual aspects of the bar, but also texture of the finished product and manufacturability. Larger oats provide more grain identity and contribute a different biting characteristic. Smaller grains hydrate more readily and have more water-binding capacity. With hydration, this makes the polysaccharides and proteins more functional."Many different grains can be used in cereal bars:
  Oat hulls are removed after the stabilization process, and what remains is called a groat. This may be used whole or ground into flour, but is most commonly used flattened. Rolled oats are made by steaming the groat and quickly flattening with a roller. Steaming makes the grain more flexible and helps denature any residual lipase enzymes that may have survived the stabilization. Quick-cooking oats are made by cutting the oats into three to four pieces before rolling; these thinner oats cook in one minute. Instant oats are thinner yet, and lose their identity more easily.   The oat endosperm contains about 7% oil. It requires stabilization through a heat and steam process that inactivates the enzymes and helps prevent rancidity. According to Bonner, this stabilization is responsible for the development of the characteristic oat flavor.   Improper heat treatment of oats can promote oxidative rancidity. Antioxidants can extend shelf life 10% to 20%; however, if grains are handled properly during toasting, they are generally not required. Pre-toasting, to increase flavor notes, can be harmful. "The level of heat required to achieve the desired flavor will also promote oxidative rancidity, and once the free-radical reaction is started it does not know where to stop," says Bonner. "So although the reaction only reaches the surface of the grain, it will continue throughout even though the center of the product has not been toasted."   Barley has a nutty flavor and chewy texture. It is used as pearled barley, with the hull removed, and as grits, flakes or flour. Fulcher explains that barley is a popular choice due to its beta-glucan levels, which are higher than those found in oats. A new waxy, hull-less form of barley has even higher levels of beta-glucan than regular barley. This, however, can cause problems in processing; when hydrated, it can contribute a high degree of viscosity and form a gluey material. In high-moisture systems, a pearled malted barley, with lower beta-glucans, might be a better choice.   Wheat is available in many forms. The whole grain is used in the form of wheat berries, or bulgur wheat, which is a parboiled, whole or crushed partially debranned wheat. The endosperm can be reduced into grits or milled into flour, and the bran can be used as an ingredient by itself. Wheat flour's properties depend on whether it comes from hard or soft wheat, and on the portion of the endosperm it comes from. It is available in both red and white forms. According to Fulcher, "red wheat tends to have a slightly stronger bitter flavor due to the phenolic compounds, and will generate a dark color when it is heated. White wheat would probably be the choice for a snack-bar application."   Corn endosperm is the portion most commonly consumed. The kernel is subject to rancidity due to high fat levels in the germ and bran, so the endosperm is usually separated from these to extend shelf life. This grain is utilized as grits, meal or flour. It is available in yellow and white varieties, which may impact the finished product's appearance.   Rice is harvested with an intact hull. Brown rice's hull is removed, but the bran and germ fractions are retained, while white rice's bran and outer layer of endosperm are removed by abrasion. These can be cut into grits or flaked, puffed or ground into flour.   Rye is related to wheat, and is similarly processed. Its distinct flavor may impact the flavor of the finished product. Unhulled rye kernels, called rye berries, add chewy texture. Rye is also found in flakes, grits and flour. Rye is very dark and will impact the finished product's appearance. White rye flour, the innermost area of the endosperm, contributes little color so it can be used in color-sensitive applications.   Other grains include buckwheat, triticale, spelt, kamut, quinoa and millet. These grains are less available commercially, and command higher prices. Their connotations of health, however, provide label appeal. Not just for breakfast  Manufacturers can blend in ready-to-eat cereals for a more open, porous snack bar. Oven- or gun-puffed grains add new textures, shapes, flavors and colors. Historically, rice has been the puffed grain of choice, but specialty puffed grains such as amaranth and bulgur wheat are now available. Low density means more costly grains can be used economically because little grain is actually used.   For oven-puffed rice, the dried kernel is softened, bumped to destroy the internal structure, and heated at around 300°C for approximately 30 seconds. The grain expands to three to five times its original size, creating an open internal texture. Gun-puffed rice, made by extruding dried dough pellets from a high-temperature, high-pressure valve, has a more dense and spongy texture, but can also be used in this application.   Extruded cereals are another option, and many branded breakfast cereals can be found in bar form. These cereals are made by cooking moistened flour inside a twin-screw extruder, then pushing the mass through a die. The pressure differential outside the extruder and the flashing-off of moisture produces a light and crispy particulate. A variety of creative shapes can be made by altering the die configuration. The finished texture is very dependent upon the chemical makeup of the grain variety. Specialty starches can be added to modify puffing and crisping characteristics, aid structural support and alter bulk density.   Flakes, made by cooking, drying, rolling and flaking individual grains, can also be used; however these forms break easily in processing. Flakes will not produce the open structure found in a bar formulated with a puffed or extruded product. Binding together  Granola bars require something other than flour to hold them together. The binding matrix greatly impacts the finished product. The binding syrup used in granola bars contains sweeteners, water, oil and flavors.   The sweetening options are extensive, and their effect goes well beyond sweetening. According to Doris Dougherty, food scientist with A. E. Staley Manufacturing Company, Decatur, IL, "alternate functions of a sweetener are to lower water activity, contribute to browning when baked, provide humectancy, aid in binding unbaked chewy-style bars, modify texture by providing either crispness or chewiness, and increase shelf life. A chewy-style granola bar, for example, would be sweetened with a more hygroscopic group of sweeteners, whereas a crunchy granola bar may use a sweetener with a higher glass-transition temperature, such as sucrose, to maintain the crunchy texture during storage." (For more information on using sweeteners, see "The Sweet Taste of Success" August 1998 Food Product Design.)   In addition to formulation functions, sweeteners in energy bars are promoted for their ability to deliver energy, whether it be in a quick jolt, or a slow and evenly sustained release. The choices are hotly debated from a nutritional perspective. Traditional sweeteners such as sucrose, high-fructose corn syrup and crystalline fructose are inexpensive and functional; however, they clash with varieties that appear more "natural." High-fructose corn syrup has taken an especially hard hit with accusations of depleting chromium levels in the body, causing temporary low blood sugar, dehydration and gastric distress.   Fruit pastes from prunes, raisins and apples provide humectancy, fat-mimetic qualities, sweetness, flavor, fiber, vitamins and minerals, all in the form of a natural carbohydrate source. Dehydrated fruit juices supply flavor and increase solids levels.   Nut butters, whether from peanuts, almonds, pecans or even roasted soynuts, are a flavorful source of protein and essential fatty acids. Soynut butter works well as a peanut butter substitute for formulating allergen-free bars. Defatted nut flours incorporate nut nutrition and flavor without all of the fat. Oils well  Most bar formulations contain fats. In addition to energy and essential fatty acids, fats and oils provide lubrication and mouthfeel, and assist with flavor release and help with machineability. "Typically I recommend canola oil," says Neal Hammond, new product director, Pacific Grain Products, Woodland, CA. "The consumer assumes that canola oil is a clean, healthful product. If labeling is less of a concern, then the less expensive soybean/cottonseed oil can be used. Peanut or sesame oil are good choices if the nut flavors are desired."   Hydrogenated fats increase bar shelf life by reducing susceptibility to oxidative rancidity. They also contribute a different mouthfeel; melting in the mouth occurs gradually and gives a continuous coating effect. The trans isomers formed by hydrogenation might be a health concern, a consideration when selecting fats.   Surfactants are often already combined with a fat source, or can be added independently. Deoiled lecithin has a low flavor impact, contributes to product release during manufacturing, prevents sucrose crystallization, helps retain moisture, and is an excellent source of nutritional choline. Adding lecithin can often lower the level of fat needed. Its lubricating properties improve processing of fat-free bars, making the dough less sticky and easier to handle. Including inclusions  A mixture of whole grains by itself might lack some excitement, so manufacturers of syrup-bound bars differentiate their products with inclusions. Kids' bars incorporate all their favorites, such as chocolate chips, marshmallows, cookie pieces and candy bits. For more appeal, extruded RTE cereal provides bright colors in fun and flavorful shapes.   Bars targeted towards adults typically need a more nutritious image. With 10% to 25% protein, nuts contribute variety, flavor and crunch. Nut substitutes made from wheat or soy can be flavored with a characterizing allergen-free nut flavor such as peanut, walnut or pecan. Seeds such as sunflower, sesame and pumpkin also have wholesome appeal. Flax has become an especially popular seed due to its high levels of linolenic and linoleic fatty acids.   Fruit, always a nutritious, value-added ingredient, comes in innumerable forms - dried or low-moisture ingredients, flakes, granules, nuggets, powders, dices and slices. Low-moisture fruits typically have a lower water activity than evaporated fruits, so they are the best choice for bars where controlled water activity is critical to prevent microbial deterioration, color degradation and texture change over time.   Because fruits are often a more expensive portion of the bar, inexpensive substitutes have been developed. For example, bland-tasting dried fruits, such as apples, can be colored and flavored with a more expensive characterizing fruit such as cranberry, raspberry or peach. Protein powers  Protein is a strategic selling point, particularly for energy bars and those designed as a "meal-in-a-bar" or nutritional supplement. "The direct consumers are people from all walks of life - athletes, hospital patients, young, old, men, women, blue collar, white collar," says Ody Maningat, Ph.D., corporate director, R&D and technical service, Midwest Grain Products, Inc., Atchison, KS. He notes that the market is sizable: According to Business Trends Analysts, Inc., the total retail sales of health/natural foods was $8.02 billion in 1998 and will grow to $12.34 billion in 2002. Of the total, health/natural snack food retail sales represented $2.81 billion in 1998 and $3.97 billion is projected for 2002. Market size of energy bars is $500 million.   "The bars currently in the market contain protein ranging from 6% to 64% of the Daily Value, depending on serving size," notes Maningat. "The recipes we have formulated contain protein that represents about 20% of the Daily Value per serving. We believe that 40% of the Daily Value is attainable with proper formulation where flavors, sweeteners, and other ingredients can be adjusted."   Depending on the project criteria, a number of protein sources are available for bars. One of the most commonly used vegetable protein sources is soy protein concentrate. Soy flour is too low in protein and too high in beany flavor, while isolates, at 90% protein, might be cost prohibitive. Concentrates, at 70% protein, contain all the necessary essential amino acids, are high in dietary fiber, and contain significant amounts of calcium, magnesium, phosphorus and potassium. With excellent moisture-retention characteristics, they can hold three to seven times their weight in water, which keeps bars moist and improves mouthfeel. They have both emulsification and fat-absorbing characteristics, which benefit higher-fat systems. Texturized soy protein (TSP) provides protein in a crisp nugget that blends with other grains without changing the texture of the bar matrix.   Another vegetable source for protein is wheat. "We know that wheat proteins are compatible with grain-based bar ingredients and a range of 20% to 40% of the Daily Value should have no adverse effect on product quality," says Maningat. He recommends three types of wheat protein for this application: wheat protein isolate, texturized wheat gluten and peptide-bonded glutamine. All are good options for manufacturers looking for GMO-free ingredients.   For protein fortification and functional properties, he recommends a wheat protein isolate with a protein content of 90%. It functions as a binder to hold ingredients together in a bar and helps set the structure of the bar or cookie and increase its strength. Another alternative is a texturized wheat gluten produced by extrusion technology. This provides a crunchy texture to a granola-type bar in addition to being a rich source of protein (60%).   For more bioactive bars, formulators might look at peptide-bonded glutamine. "Glutamine peptide is a bio-active peptide that is important in sports nutrition and clinical nutrition," explains Maningat. "In sports nutrition, it plays a key role in prevention of fatigue and overtraining syndrome in athletes. It helps athletes recover faster after exercise and reduces the risk of infections after prolonged strenuous exercise. It enhances glycogen storage in the muscle. In clinical nutrition, glutamine peptide speeds up the recovery of critically ill patients. It is required by the body's defense system during stress." Peptide-bonded glutamate is a low-molecular-weight, water-soluble wheat protein with a clean, non-bitter flavor. It exhibits improved emulsification and foaming capacity. The ingredient has 75% protein content and functions as a rich source of glutamine peptide (about 30%).   Nuts in the form of butters, defatted flour, and chopped nutmeats also add protein, with the added benefit of flavor. However, due to their high fat content they are typically not used as the sole protein source.   Animal protein sources include egg white and dairy ingredients. These are excellent protein sources, but would not be acceptable in the vegetarian market. Nonfat dry milk contains only 36% protein, but at 80% protein, whey protein is a good choice for fortification. "Whey protein contributes to water-binding characteristics, gelation and Maillard browning," notes Kimberlee Burrington, coordinator of the Whey Applications Program at the Wisconsin Center for Dairy Research, Madison. "Whey is bland in flavor, where soy can contribute more flavor than may be desired. Whey is also perceived as a natural and label-friendly ingredient."   Sodium or calcium caseinates, containing 90% protein, promote emulsification, water binding and increased viscosity. An added benefit is their whippability for creating a chewier texture in bars with creamy centers. Aside from contributing calcium, the opacity of calcium caseinate can create a creamy, white nougat-like appearance. Often, blends of soy, whey and casein present the best of all ingredient options. No bar to nutrition  Some bar manufacturers wanting to promote their products as a good source of fiber as defined by the FDA use additional fibers to bulk up the content. Grains can range in fiber content from 2% (corn) to 11% (buckwheat), but many bars require supplemental sources. Bran is often considered a high-fiber ingredient, but typically it contains less than 50%. More concentrated forms of fiber include pectins, gums, psyllium-seed husk, oat-hull fiber and pea fiber. Whether soluble or insoluble, fiber can impact product processing by affecting water-binding capacity, finished-product texture, flavor and appearance.   In fortified bars, stability, flavor and nutritional assays become key concerns when selecting a nutrient blend. RTE cereals are typically fortified to meet 25% of the Daily Value, but energy bars can reach levels of 100% or more. To compensate for losses over time, many levels are increased by 50% or higher to ensure label claims at the end of shelf life. This can lead to objectionable flavors and, possibly, colors.   Herbs and nutraceutical supplements are the latest way to add value to energy bars. Bee pollen, chromium picolinate, isoflavones, ginkgo biloba, ginseng, spirulina, antioxidants and probiotics are just a few examples of the ingredients added to promote increased brain power, oxygen absorption or free-radical scavenging. Often, the level required to achieve any therapeutic effect from these ingredients is too high to make the food palatable. Also, whether or not these ingredients contribute the same degree of beneficial health effects as the original sources remains to be seen. Sweet taste of success  A good flavor system is important in any product. In cereal bars, well-balanced flavors cover up any naturally occurring objectionable notes in the ingredients, such as strongly flavored grains, protein or nutritional supplements. In the case of granola bars, the starch in the grains is not completely gelatinized due to the lack of hydrating water and heat, thus flavors and sweeteners are important in covering up any undesirable flavor notes coming from the raw starch.   Flavors often react chemically and/or physically with the fat, protein and carbohydrate fractions of the snack bar. These interactions include flavor complexing and/or masking, partitioning, and altered delivery time, which can unbalance the system. It is important to discuss the ingredients that make up the base with the flavorist so that the proper system can be selected.   Sweeteners also affect the flavor of a product by contributing a certain intensity and by changing the flavor character and delivery. The overall sweetness of a product also impacts flavor usage. The rule of thumb is that mildly sweetened products require lower flavor usage levels because the flavor comes through more clearly. With very highly sweetened products, higher flavor usage levels are required as the sweetness intensity increases, masking the overall flavor.   Sweeteners also contribute their own flavor. Sucrose has a clean sweetness; honey has a floral sweetness; molasses, malt syrup and brown sugar contribute dark notes; while polyols contribute bitterness or a cooling sensation. Non-nutritive sweeteners can also contribute bitter or metallic notes. The characterizing flavors of sweeteners such as honey, brown sugar and molasses can supplement the flavor of less expensive sweetening systems as an economical alternative. Characterizing flavors can be used if the functional properties of a particular sweetener are unwanted.   Processing will also impact flavor usage. As granola bars do not see high-heat treatments, evaporative losses are minimized, so less flavor should be needed for these applications. The process does not promote Maillard-reaction and caramelization flavors, so they must be added. Baked bars also require the use of bake-stable flavorings containing low levels of alcohol, which has a tendency to flash off.   Hurdling the challenge of bar formulation means achieving a balance of flavor, nutrition and functionality. But once the balance is successfully achieved, the product will leave the competition behind.  Lisa Kobs, M.S., is a Minneapolis-based food scientist and technical writer with a focus on new product development.Back to top

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