July 1, 1999
By: Kimberlee J. Burrington
The appeal of cookies and crackers spans all ages and occasions. Whether they're fun, convenient, indulgent, healthy, upscale, or otherwise, it's the marketing person's challenge to develop concepts for new cookies or crackers and gauge the appeal that they will have for the consumer. Then, it's up to the product developer to transform these concepts into finished products with the taste, texture and appearance that will keep the consumer coming back for more. Fortunately, more and better ingredients, processes and packaging help product designers formulate these snack favorites. And yet, with all of the latest technology to choose from, some of the basics are still necessary.
Why the cookie crumbles Cookies are a unique example of a snack food that, in years past, was a homemade item for most people. For a few, they still are. And while some consumers want homemade taste, texture and appearance in the cookies they buy at the store, comparing a homemade, fresh-out-of-the-oven cookie to one sitting on the shelf, with a shelf life of up to 6 months, is just not fair. (Besides, that crispy-on-the-outside, chewy-on-the-inside homemade cookie won't stay like that for long.) In fact, it's the same consumers that make homemade cookies that often ask what "preservatives" are in the store brands that make them taste good for so long.
It may come as a surprise to them that most store cookies have the same basic ingredients as homemade cookies - flour, shortening (even butter), sugar, sometimes eggs, baking soda, salt and flavor. However, the ability to vary, combine and add to these ingredients, and achieve the desired organoleptic qualities, requires the creativity and knowledge of a food scientist.
Flour, sugar, shortening and chemical leaveners are the primary functional ingredients of cookies. Varying the types and quantities of these ingredients yields different dough rheologies and finished eating qualities, which are often classified by the processes - rotary, wire-cut, deposited and coextruded - used to produce the cookies.
For a rotary-molded cookie, such as a sandwich-cookie base, dough is forced into molds on a rotating roll. As the roll turns, the baking band extracts the formed dough piece from the molds. To maintain the molded design of the cookie, rotary doughs contain very low levels of shortening and sugar to prevent excessive spread. Oils do not function well in this case, because they lack shortening's ability to hold dough together during the molding process.
Wire-cut cookies have more sugar and shortening than rotary-molded cookies. (Your favorite chocolate chip cookie on the shelf is most likely a wire-cut cookie.) Relatively high amounts of water and eggs are used, so that the dough will hold together during the cutting process. A higher water content means that excessive mixing or handling of the dough can lead to over-development of gluten and decreased tenderness. A tender product is produced by incorporating shortening with the flour into the dough or batter, prior to adding water. Any fat retards the adsorption of formula water by the flour, and thereby limits gluten protein development.
Flour is the main ingredient in most cookies. Cookie flour is predominantly milled from soft wheat varieties. Unlike bread doughs, gluten development is not present in optimally mixed cookie doughs due to the limitation of water, and competition between gluten proteins and sugar ingredients for water's association. Water level and sugar concentration play a role in restricting gelatinization and irreversible swelling of starch in the flour, although internal baking temperatures do not reach a level where this change could occur.
Shortening in cookies coats the flour particles and renders them less available to water. Generally, cookies are formulated with high levels of sugar and vegetable shortening, or butter, and low levels of water. Both rotary-molded and wire-cut cookies can contain fat and sugar levels of up to 50% to 75% of the flour weight.
Sugar or other sweeteners determine dough and product properties. Sucrose contributes sweetness and flavor, as well as surface color via caramelization. Granulated sugar has several effects on finished cookies. As sucrose content increases, it acts as a hardening agent, creating a crisp, firm texture. Granulation affects creaming, spreading of the cookies during baking, and surface texture of the cookies. As cookies are baked, undissolved sugar melts and the dough spreads on the cookie's baking surface. Coarse forms of granulated sugar dissolve less readily than fine granulations; a coarser granulation of sugar results in less spreading of the dough and more surface cracking of the baked cookie. Surface cracking results from the recrystallization of the sugar at the surface of the cookie.
Chemical leaveners such as sodium bicarbonate and ammonium bicarbonate are the most common agents used to leaven cookies. Carbon dioxide generated during heating enhances the leavening action of steam and entrapped air. Leavening cookies produces an increase in total volume of the cookie and an alteration of the width of the cookie in relation to its height, which is referred to as spread ratio. Spread can also be influenced by flour chlorination, by adding emulsifiers to the dough, or by adding certain enzymes.
Concerning crackers In contrast to cookies, crackers contain little or no sugar. They are formulated with higher-protein flours, often a mixture of hard and soft wheats. Crackers contain somewhat high levels of fat (10% to 20%) and low levels of water (20% to 30%) compared to bread. Both yeast-fermented and chemically leavened varieties are common.
Fermented crackers use a sponge-and-dough process in which sponge fermentation takes about 12 to 18 hours. Once the sponge is ripe, it is mixed with the remaining flour and other ingredients, and sodium bicarbonate is added to bring the acidic dough back to pH 7.0. Unlike cookies, gluten development is important in a cracker to create the right dough rheology and finished texture. After 2 to 5 hours, the dough is processed by coarsely rolling, lapping and layering it, then reducing the layers through sheeting rolls. Chemically leavened crackers skip the fermentation time and have a relatively short lay time prior to rolling.
The remaining processes are the same for both fermented and chemically leavened crackers. Before baking, the dough sheet is continuously cut into crackers and rolled with docking pins. The docking pins press the dough together to facilitate steam release from the crackers and help keep the layers from separating. The high-temperature, short-time bake puffs the thin dough sheets into crackers by vaporizing internal water. Salting is done prior to baking. If oil is sprayed or seasoning applied to the crackers, this occurs after the bake. Low moisture content in the finished product is important for preserving the crisp and brittle, but tender, cracker texture. Most crackers contain approximately 2% moisture.
Choosing the right fat Shortenings lubricate, aerate and affect eating quality and spread in a cookie. Fats with higher levels of solids tend to have the least effect on spread, while fats with very low solids have a greater effect. "Cookies typically use margarines, all-purpose shortening, filler-fat shortenings, butter and butter blends as shortening sources," says Bob Johnson, team manager for food processor R&D, Bunge Foods Corp., Bradley, IL. "Butter blends are an economical way to add the flavor and functionality of butter to a cookie. They contain 20% to 60% butter in combination with hydrogenated vegetable oil, mono- and diglycerides, salt, lecithin, sodium benzoate, flavor and vitamin A," he adds.
All-purpose shortenings are the type most commonly used in cookies and crackers. These shortenings are not emulsified, because in some applications, the emulsifier may become too intimately mixed with the dough, resulting in a less desirable product. Performance of an all-purpose shortening is very dependent upon adequate control of the mixing process. To maintain a consistent plasticity, bakers formulate with strong beta-prime-tending fats. "All-purpose shortenings typically have a solid fat index ranging from 42% at 10°C to 8% at 40°C," says Johnson.
Crackers generally get most of their fat content from spray oil applied after the bake - a small amount of dough fat is present for texture and machinability. "Spray oils for crackers are usually high-stability oils which are either identity-preserved oils that have higher stability, or are partially hydrogenated and fractionated," notes Johnson.
Dough control The chemical leavener sodium bicarbonate, also called baking soda, was first used about 500 years ago, when it was discovered that it raises and tenderizes baked foods without a time-consuming fermentation. Originally the bicarbonate was reacted with naturally present food acids such as lactic acid from buttermilk, or added acids such as tartaric acid (cream of tartar) or vinegar.
One of the first leavening acids used was monocalcium phosphate (MCP), followed by sodium aluminum sulfate (SAS); combining these two acids gave rise to double-acting baking powder. Today, there's also anhydrous monocalcium phosphate (MCP-Anh), sodium acid pyrophosphate (SAPP), dimagnesium phosphate (DMgP) and dicalcium phosphate dihydrate (DCP).
These acids react with the bicarbonate source at different rates and temperatures. Each acid has specific neutralizing and equivalence values that aid in determining the quantity needed. Integrating these acids with a bicarbonate source is not as critical in a cookie or cracker for structure-setting and final-product quality as in other baked products. (For more information, see "Leavening Systems: Making Products Rise and Shine" in the March 1995 issue of Food Product Design.)
Cookies, and some crackers, are leavened by steam, carbon dioxide from the decomposition of soda, and ammonium bicarbonate. Sodium bicarbonate in cookie doughs both raises the pH and gives some leavening effect. However, the higher pH can have an inhibitory effect upon the structure-setting reactions, and the finished cookie may actually have a lower height.
Typically, the faster-acting leavening acids, such as MCP or cream of tartar, are not used in cookies, because the creaming stage incorporates air bubbles that serve as nuclei for the leavening gases generated during baking. If MCP is added to the dough, carbon dioxide is generated during mixing and the early stages of baking. Cookie height and actual volume are increased with MCP.
Ammonium bicarbonate is frequently used at 0.5% to 1.0% flour basis in lower-moisture cookie doughs, such as rotary doughs. This ingredient is not recommended for soft cookies, or in a cookie with a finished moisture content greater than 5%, because traces of ammonia may be retained, giving an ammonia taste. Ammonium bicarbonate does not affect cookie pH, but it increases cookie volume. It must be uniformly distributed throughout the dough, and should first be dissolved in water, and then added to the mixer, because undissolved particles cause large "blowouts" in the product.
Enzymes are another important type of ingredient affecting the physical properties of dough. The two classes of enzymes important for baking are amylases, found in certain cereal grains, and proteases from microorganisms such as yeast and fungi. Amylases, which are added to or already present in the flour, help control the speed of yeast fermentation by releasing starch molecules for yeast digestion. Proteases vary in function. Exoproteases liberate the terminal amino acids of protein molecules, enhancing color formation during baking by allowing participation of free amino acids in Maillard reactions. Endoproteases are more effective for dough softening, due to cleavage of the internal peptide bonds.
Cookies, except for those that might be sheeted, do not require supplementation with enzymes. If a sheeting process is required, then proteolytic enzymes of bacterial origin, such as Bacillus subtilis, are recommended because their optimum pH (7.3 to 7.5) activity is close to that of cookie dough. Dough temperature is critical, as the activity of the enzyme doubles with each 50°F increase in temperature.
Enzymes make cracker doughs more elastic, so that cutting and sheeting are easier. Proteases can reduce the mellowing time of sponge doughs by as much as 25%. For straight or no-time doughs, the mixing time is not changed, but a definite improvement in machinability occurs.
Crackers can also utilize reducing agents such as L-cysteine, sodium bisulfite and other bisulfite compounds to modify gluten functionality by cleaving its disulfide bonds. These reactions increase dough extensibility; reduce the development times of gluten formation (thus decreasing the required mix time); and soften the dough. Fumaric and sorbic acids also affect doughs by decreasing their elastic properties.
Emulsifiers in cookie and cracker formulas improve ease of extrusion; control greasiness; increase moisture retention; provide fat-sparing characteristics; improve mixability; and facilitate release in rotary-molded cookies. Lecithin is one of the most common emulsifiers used; others include mono- and diglycerides, diacetyl tartaric acid esters in cookies, and sodium stearoyl lactylate in crackers.
Adding strength and endurance Fiber from many sources can be added to cookies and crackers. These include amaranth, bran, barley, cellulose, citrus, corn bran, flaxseed, fructooligosaccharides, fruit, inulin, oat bran, oat fiber, peas, prunes, psyllium, resistant starches, rice bran, soy, sugar beet, sunflowers, vegetables, wheat bran and white wheat, as well as some gums and stabilizers. Gums that add to fiber content include carrageenan, guar, gum arabic, konjac, locust bean gum, sodium carboxymethylcellulose and xanthan gum.
These all contain different amounts of soluble and insoluble fiber. (More information on the benefits and functionalities of these fibers can be found in "New Ways to Apply Fiber," October 1996 Food Product Design and in "Dietary Fiber: A Healthy Discussion," January 1999 Food Product Design.)
Many fibers today have been improved by providing controlled water absorption and customized particle size, with no off-flavors. Some may be well-suited to a particular cookie or cracker - it's a matter of trial and error, and lots of baking and tasting, to discover what fits a formula.
"Oat fiber is a multifunctional ingredient that is especially well-suited to cookie and cracker applications," observes Rob Hardy, marketing manager, Opta Food Ingredients, Bedford, MA. "Oat fiber's functionalities include structure reinforcement, improved shelf life and adding dietary fiber," he says.
Says Cathy Porcella, senior manager, applications and technical service, Opta Food Ingredients, "Oat fiber can be added to a cracker formula at a 1% to 2% usage level to decrease defects such as checking. The long flexible structure of the fiber provides strength to the cracker, which reduces the amount of breakage."
If breakage isn't an issue, but you have a soft cookie with some shelf life needs, fibers also function well for this purpose. "Oat fiber improves the shelf-life of a soft cookie by its high water-holding capacity and ability to maintain moistness," says Porcella. A 2% to 3% usage is a typical level to extend shelf life. For a fiber claim, 3% to 5% oat fiber will be necessary.
For special dietary products with beneficial effects exceeding those of typical fiber, some other ingredient choices exist. "Ingredients such as konjac flour and resistant starch both have application in diabetic-type products because of their slow digestibility and resulting sustained energy release," says Hardy. "Both ingredients have been shown to have a prebiotic effect in the gastrointestinal tract by promoting the growth of beneficial bacteria."
Konjac is a very high-molecular-weight polysaccharide composed of glucose and mannose sugars, while resistant starch results from the typical retrogradation of starch. High-amylose corn starches are generally the source for resistant starches, which are not digested in the small intestine, but are fermented in the large intestine. Like soluble fiber, they increase transit time in the GI tract, increase fecal bulk, and release short-chain fatty acids in the colon.
Creating better organoleptics Liquid sugars such as invert syrup, high fructose corn syrup, corn syrups and honey are added primarily as humectants and sweeteners in soft cookies. These sugars do not contribute to spread and do not recrystallize. Their humectancy also extends shelf life of soft cookies by reducing water activity. Brown sugar is added for sweetness, texture and flavor. In some cases, a combination of molasses and granulated sugar is substituted for brown sugar, because of lumping problems that can occur when brown sugar absorbs moisture during storage. If sweetness without calories is a requirement, there are many approved non-nutritive sweeteners that are stable under baking temperatures. Sucralose, acesulfame-K and certain encapsulated forms of aspartame are a few that will hold up in the oven.
Eggs, typically added in dried form as whole egg powder or egg white powder, are commonly used, but not ubiquitous, in cookies on the shelf today. Eggs provide foaming, emulsification and binding attributes. They contribute to a more tender texture, but might be cost-prohibitive in some cases.
Dairy ingredients such as milk powders or whey are used in cookies and crackers for their contributions to structure, flavor and browning characteristics. In the early days of dairy ingredients, they sometimes replaced flour in cookies because of the cost advantage. Later, bakers discovered dairy ingredients' other benefits, including improved shelf life.
Carbohydrates also have a place in cookies. Many starches have been developed for use in reduced-fat bakery applications. Starches contribute to the finished structure of cookies, and pregelatinized types are used for moisture retention and softness in soft cookies.
Flavors and seasonings "Taste still rules when it comes to consumers' purchasing habits for cookies and crackers," says Teri Mascuch, marketing manager, McCormick & Company, Inc., Hunt Valley, MD. One of the most pleasant and universally accepted flavors for cookies is vanilla. Vanilla notes can be added in many forms and types, from gourmet Bourbon vanilla to economical vanillin.
There are also many other flavors that give cookies a distinctive flavor note. "Sweet-brown, chocolate, and cooked-milk flavors are popular for new cookie applications," says Mascuch. "Cooked-milk flavors like dulce de leche and tres leches are causing interest in new cookie applications. Cooked-milk flavors are common for Hispanic consumers, and these influences are becoming more mainstream." Look for these flavors in new cookie introductions - many of them are already showing up in ice cream.
Sweet flavors are always a treat, but what about the savory side of the aisle, the crackers? "Popular flavors for crackers are cheese flavors - Cheddar-types and smoother, milder cheeses that come from the Hispanic market," says Mascuch. Cracker flavors can be put into the dough, as well as added as a seasoning blend for extra impact.
Cracker seasonings often follow the consumer trends for salty-snack seasonings. "One of the trends in the 12-to-15 year old consumers is their taste for savory seasonings on snack foods," says Nancy Farace, technical marketing manager, McCormick & Company, Inc. "They prefer corn-based products, with cheese, tomato, garlic, red pepper, and some heat added to the product. This seasoning preference can be applied to cracker tastes as well."
Adding fun and variety One of the ways to differentiate cookies and crackers is by appearance. Changing shapes, sizes, toppings and inclusions adds fun and variety to snacking choices. Shapes and sizes alone have created a whole new world of cookies and crackers, for young and old alike. (We've come a long way from animal crackers.) The food scientist is limited only by the dies and cutters that a manufacturer is willing to make, and the cost of making new ones.
In some cases, food product designers may want to extend or improve the appearance of a topping by atypical means. "There are colored pieces that can be used as an inclusion or a topping in a cookie or cracker that have good integrity during the mixing and baking process," says Farace. "They are made by an extrusion process, and are either made with corn starch, wheat flour or corn flour. One application for these pieces gives a look of Parmesan cheese to a topping, without browning problems.
"Colored particulates can be used to visually replace spices and herbs in seasoning blends as well," continues Farace. "This allows for control of color and flavor in the finished product. For instance, they can be used in a seasoning mix to give the appearance of added parsley without the adherence problem that parsley has."
For more than just color in a topping or inclusion, try adding fruit and flavor. Choose pieces from an array of fruits to add interest and differentiation to a new cookie. "If a product developer is interested in a fruit piece that retains its integrity during mixing, there are diced pieces containing 50% to 20% fruit," says Jennifer Burke, senior food technologist, Universal Flavors, Fenton, MO. "They are low in water activity, high in solids, and come in different sizes and flavors. They contain fruit, pectin, sugar and flavor, so they have a clean label."
Another way to deliver fruit in a cookie is with fillings that can be coextruded with dough. Fruit fillings for cookies have gone way beyond fig paste. "Flavors for bakery fillings seem to be following the trends of top-selling desserts in restaurants," observes Burke. "Fruit cremes, white chocolate and cheesecake flavors are popular for filled-cookie applications."
Don't forget the chocolate Chocolate on the inside, chocolate on the outside, or chocolate used as an inclusion - for some cookie-lovers, chocolate just has to be included. Blending chocolate liquor with sugar, dry-milk solids, lecithin, vanilla and/or vanillin composes most of the chocolate ordinarily consumed.
Chocolate is delivered in many forms in cookies. Labels commonly list chocolate liquor, chocolate chips, milk chocolate, cocoa powder, dutched cocoa, white chocolate and chocolate-flavored coating.
Cost, temperature stability and fat bloom are probably the biggest issues with chocolate products in cookies. Compound coatings are most commonly used for partially or totally enrobing cookies in a chocolate-flavored shell. Under current U.S. standards of identity (21 CFR section 163), the term "chocolate" is allowed only for products made with chocolate liquor and cocoa butter. Compound coatings tend to be less expensive, more stable to temperature changes, and more resistant to bloom than chocolate coatings.
"Viscosity is the most important property of coatings, followed by color, fineness, and fat percentage," says Ted Hanneman, director of R&D, Barry Callebaut USA, Inc., St. Hyacinthe, Quebec, Canada. Instead of cocoa butter, compound coatings utilize hard fats such as partially hydrogenated lauric fats (palm kernel oil), or partially hydrogenated, fractionated vegetable oils (soybean or cottonseed). The melting curves for these fat systems are not as steep as cocoa butter and they do not require tempering. "The faster the fat melts, the better the coating tastes," says Hanneman. In warm climates, a compound coating with a high melting point will not smear on wrappers or on the consumers fingers.
"Chocolate chips or chunks may deliver a soft or hard finished baking quality," says Hanneman. "Foodservice or home suppliers prefer a softer chip after the bake so it is soft to bite into. Chips for industrial use are formulated with a higher level of dextrose, so they are firmer after bake and do not smear in packaging equipment." He continues, "In a high-moisture cookie, bloom problems in a chip can be avoided by making sure that the chips have been exposed to enough heat in the oven to set the chip and physically entrap the fat inside the chip."
Chocolate chips come in a multitude of flavors, sizes and shapes. Chocolate-chip manufacturers differentiate their products by changing sweetness, adding milk solids, or by adding different vanillas or vanillin. Sweet chocolate chips contain a minimum of 15% chocolate liquor. Bittersweet, or semisweet, is the darkest edible chocolate, with the highest percentage of cocoa butter, at least 35%. Sweet and semisweet chocolate are usually formulated with 12% milk solids. Milk chocolate must contain more than 12% milk solids and greater than 10% chocolate liquor. White chocolate chips are a blend of cocoa butter, milk, sugar, and flavor, and have a similar composition to milk chocolate. Technically, white chocolate is not chocolate because no chocolate solids other than cocoa butter are present.
Another way to deliver chocolate to a cookie formula is pan-coating chocolate morsels with a colorful candy shell.
Cocoa is the powdery remains of chocolate liquor after most of the cocoa butter has been removed. Dutched cocoa is cocoa powder that has undergone treatment with an alkalizing agent to modify color, flavor and dispersability. Dutched cocoa is often used in a cookie to provide more chocolatey flavor and darker color. Extreme treatments produce black cocoa powder, which helps give the characteristic flavor and color of an Oreo®-type sandwich cookie.
Just nuts Nuts add visual, textural and flavor appeal to cookies and crackers. Few food items have as much of an international appeal as nuts - most cultures have been exposed to nuts of many varieties. Commercially cultivated nuts include almonds, apricot nuts, Brazil nuts, butternuts, cashews, chestnuts, hazelnuts, heartnuts, hickory nuts, macadamias, pistachios, walnuts, pinenuts and, of course, peanuts.
"Pistachios are a new nut for use as an ingredient in cookies," says Tom Mack, director of quality assurance, Paramount Farms, Lost Hills, CA. "Pistachios are available in whole kernels, dices, and now slices. The technology is available to achieve more than one shell fragment per 100 lbs. of pistachios or almonds."
Nuts are all high in fat, most over 70%. The presence of a high lipid content can present special problems for processing and storage of products containing nuts. Damage to the kernel during shelling can result in enzymatic, hydrolytic or oxidative rancidity (mainly due to unsaturated lipids) that leads to a shortened shelf life. "Better stability is a benefit to using pistachios because they do not develop rancidity like other nuts," says Mack. On the benefit side, nut lipids are very important precursors for the formation of roasted or toasted nut flavor. Nut proteins and carbohydrates also play a flavor role, as precursors for Maillard-reaction flavors.
Baking contributes to the formation of additional flavor compounds in nut-containing cookies. Some formulas can take advantage of this by using raw nuts, given that the typical roasted-nut flavor will develop during the baking process. Roasted nuts yield an even stronger nut flavor in the baked cookie. Two classes of flavor compounds are responsible for heated-nut flavors. One is a series of various lactones, such as g-octalactone and g-decalactone, which are derived from direct thermally induced lipid degradation. The other class is heterocyclic-nitrogen or oxygen-containing compounds, represented by pyrazines and furans.
Wrapping it all up More and more bakers are choosing packaging materials not only for their barrier properties and ability to maintain finished-product integrity, but also for their visual appeal.
Using packaging to strengthen a brand identity is increasingly important on crowded grocery shelves. Enhanced graphics, shiny or matte-finished film, superior design, digital printing, more colors, and the ability to reseal the package can make that tasty cookie or cracker even more appealing. Convenient package sizes are also a big attraction for cookie and cracker eaters.
Stand-up pouches and canisters offer convenience, product differentiation and good barrier properties. Both are recloseable and portable. New polyester films for oven- and microwave-safe lids and flexible-packaging applications, as well as better liner sealants for easy-open access and improved seal integrity, also offer improved packaging options. Additionally, metallized OPP (oriented polypropylene) structures present an alternative to metallized polyester, foil or some coated films.
With tasty and convenient products on the inside, and a good-looking package on the outside, the stage is set for successful product introductions that take advantage of both tried-and-true techniques and innovative technologies for cookies and crackers.
Kimberlee J. Burrington is the whey applications program coordinator for the Wisconsin Center for Dairy Research in Madison, WI. She received her B.S. and M.S. degrees in food chemistry from the University of Wisconsin-Madison. Her industry background is in bakery and dairy.Back to top
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