Uncovering Chocolate and Compound Coatings

March 2003

Uncovering Chocolate and Compound Coatings

By Ronald C. Deis, Ph.D.Contributing Editor

Take a walk around any mall and notice the number of stores devoted to chocolate. Mentioning chocolate to a consumer may elicit many thoughts, feelings and cravings: a flavor, an aroma, a sensation, a texture or an expectation.

By an interesting twist of fate, it turns out that this flavor we crave is also good for us. How often does that happen? Recent studies have shown that chocolate, in addition to satisfying our taste buds, may reduce the risk of cancer and heart disease, and its primary saturated fats do not raise cholesterol levels. Eating chocolate also boosts serotonin levels in the brain, helping calm and relax us, and increases endomorphins, lifting our mood. Chocolate tastes good, makes you feel good and wards off potential future health problems — what’s not to love?

A deep demandAccording to a poll conducted last year by the Chocolate Manufacturers Association (CMA), Vienna, VA, 57% of women and 46% of men chose chocolate as their favorite flavor (strawberry and/or other berry flavors, and vanilla tied for second at a distant 12%). The Vienna, VA-based National Confectioners Association conducted a survey noting consumers prefer milk chocolate 2-to-1 over dark chocolate, but preference for dark chocolate climbs with age, so this ratio is slowly changing as baby boomers get older.

Chocolate confections represent a big business that continues to grow, even in tough times. CMA adds that in 2001, U.S. apparent confectionery consumption was 7.0 billion pounds, with 3.1 billion pounds of this being chocolate. On a dollar basis, chocolate is an $8.5 billion business wholesale, translated into $13.1 billion at retail. The overall business continues to grow, accelerated by increases in gift-box chocolates, sugar-free and diet products, and snack and granola bars.

What should we call it?Let’s start by defining chocolate — first by use, then by regulatory standards of identity for the type of chocolate, set by FDA in cooperation with industry. Consumers are most familiar with chocolate sold by the bar as “eating” chocolate, a name that is self-explanatory. These contain 28% to 32% cocoa butter and, as noted before, can be milk chocolate or “sweet” dark chocolate.

Chocolate for industrial use is referred to as couverture chocolate, and is used for panned candies, truffles, dipped chocolates, molded and shaped chocolates, baked goods, nutritional bars, and ice cream. Couverture’s high fat content (28% to 32%) imparts easy melting and tempering, great texture, and makes it easier to work with in enrobing and dipping applications. It is most widely used in biscuit and nutritional-bar applications, closely followed by confectionery. Other uses are ice cream (bars and cones) and other baked products.

Rather than using chocolate, many coated baked products and nutritional bars opt for a compound coating, which is less expensive and, sometimes, easier to use. Compound coatings use hard vegetable or “tropical” fats in place of cocoa butter.

Developers interested in baking with chocolate may instead choose baking, or “bitter,” chocolate, which has a lower cocoa-butter content and high chocolate-liquor content compared to all other varieties, giving it a more intense flavor. Baking chocolate does not include any sugar, but may be flavored with vanilla.

Using cocoa powder in baked-product applications can also convey chocolate flavor. Cocoa powder is the powder remaining after most of the cocoa butter is removed from chocolate liquor, but it can have a wide range (0% to 24%) of cocoa-butter content. Another form of this are “dutched” cocoas, which have been alkalized — dutched — to modify color, flavor and dispersion properties. These are often marked by an intense black color. “For round numbers, about one-third of cocoa powder produced is natural,” says J. William Ryan, vice president, confectionery sales and marketing, ADM cocoa division, Milwaukee, “and the remaining two-thirds is alkalized. The bakery segment is the largest user.”

Title 21 of the Code of Federal Regulations (CFR), part 163, states the industry has specified “requirements for specific standardized cacao products.” Standards are defined for: cacao nibs, chocolate liquor, breakfast cocoa, cocoa, low-fat cocoa, cocoa with diocetyl sodium sulfosuccinate for manufacturing, sweet chocolate, milk chocolate, buttermilk chocolate, skim-milk chocolate, mixed dairy-product chocolates, sweet cocoa and vegetable-fat coating, sweet chocolate and vegetable-fat coating, and mild chocolate and vegetable-fat coating. These definitions include specific required ingredients, optional ingredients and labeling requirements for certain exceptions.

Milk chocolate must contain at least 12% milk solids and not less than 10% chocolate liquor. As stated in the standard of identity, a sweet, or dark, chocolate must contain at least 15% chocolate liquor and less than 12% milk solids. German chocolate (not a standardized name) — a sweet chocolate often used in baking — originated with an English immigrant, Samuel German, who marketed the product in Massachusetts. Bittersweet, or semi-sweet, chocolate is the darkest eating variety, and must contain at least 35% chocolate liquor. In January 2003, the FDA published the final rule (21 CFR, section 163.124) for white chocolate, which contains no chocolate solids other than cocoa butter. It must contain at least 20% cocoa butter, at least 14% total milk solids and no more than 55% nutritive carbohydrate sweetener. This standard resulted from a 1993 CMA petition to alleviate the need for temporary marketing permits to use the name “white chocolate.” Prior to 1993, these products were labeled “cocoa-butter confectionery.”

Tracing traditionCacao originated in Mexico, but the Spanish found that the cacao tree (Theobroma cacao) — responsible for producing the fruit pod in which cacao beans are found — would grow in any tropical region within about 20 degrees of the equator. Cacao trees are cultivated today throughout South and Central America, the West and East Indies, and West Africa. West Africa produces nearly 70% of the world’s output, pooling the resources of the Ivory Coast (by far the largest producer of cocoa today), Ghana, Nigeria and Cameroon. Other sources include Indonesia, Brazil, Malaysia and Ecuador. These trees grow about 20 ft. in height and are susceptible to many diseases, as well as damage from the sun and wind. The average cacao tree produces 20 to 30 pods per year, each yielding only about 2 oz. of dried beans. The pods are cut open on the ground and the beans are immediately fermented, then dried in the sun. “Different bean origins have different characteristics,” notes Ryan, “so we try to meet our customer’s needs by offering a variety of cocoas that vary in fat content, flavor, pH and color.”

For the past five years, the connection between the harvesting of the beans, and slave- and child-labor practices has been the subject of great controversy, primarily in the West African countries that produce the bulk of the world’s supply. Much of the problem was perpetuated by the low prices for cocoa due to oversupply. The chocolate industry responded by establishing the Geneva-based International Cocoa Initiative (ICI). This organization works with the International Labor Organization (ILO), Geneva, and other government organizations to better understand cocoa-related labor issues and farming practices. In November 2002, the ICI, the ILO and these other organizations announced the formation of pilot programs to address slave- and child-labor issues, and to improve farming practices.

Upon receipt, processors first thoroughly clean the cacao beans, then traditionally roast them in gas-fired drums at 400ºF and, finally, rapidly cool them. The beans are shattered into fragments, called nibs, and separated from their shells.

One of the newer processing approaches is to heat the beans with infrared heat. This expands the shell so that processors can easily crack it off, which allows more-effective roasting of the nibs prior to grinding. The nibs are commonly milled in hammer mills, then finely ground in a stone or ball mill to produce a fine mass and remove grittiness, resulting in a chocolate liquor. “What makes a good liquor,” states Ryan, “depends on different origins; low, medium and high roasting; and dwell time. These conditions all influence and distinguish flavor.”

Another roasting method is to actually roast the liquor at this point. This liquor can then undergo several processes. Hydraulic pressing of chocolate liquor yields cocoa butter and cocoa powder. For baking chocolate, the liquor is “conched” to further refine and develop the flavor and richness of the product. Conching is a mechanical kneading of the chocolate mass to intimately mix all phases, remove moisture and volatile flavors, and improve viscosity and melting characteristics. Lecithin and cocoa butter can be added to improve viscosity and handling characteristics. The chocolate is then processed through five-roll refiners to reduce particle size to less than 25 microns. After this, it is tempered and moulded, then cooled into blocks for use as unsweetened baking chocolate.

Producing any standardized chocolate product is then a formulating process that depends on the needs of the final user. For example, milk chocolate contains 10% to 20% chocolate liquor, about 45% sugar, about 20% cocoa butter and approximately 15% whole milk solids; a sweet, or dark, chocolate could contain about 35% chocolate liquor, approximately 50% sugar and about 15% cocoa butter. Manufacturers mix these ingredients together, conch the mass, and then roll-refine it to a desirable particle size, temper it, mould it into final form and cool it. White chocolate is similarly processed using only cocoa butter, sugar and milk solids. The percent sweetener, cocoa butter and chocolate liquor depends on the final destination of the product — bakery, confectionery, ice cream, etc. Each product use dictates sweetness, bitterness, darkness, smoothness, flow characteristics and use of optional flavoring ingredients as outlined in the standards of identity.

Compounding the processCompound coatings are based on lauric or nonlauric hard butters, rather than on cocoa butter, and cocoa powder frequently replaces a large portion of chocolate liquor. The components of a compound coating are often dictated by the end product or by the imagination of the coating producer, rather than by the standards.

Particle-size constraints are very different due to the types of products coated. Refining a coating to 25 microns or less is often not required for coatings applied to part of a nutritional bar or a cookie that breaks into larger pieces in the mouth.

In the past, compound coatings have traditionally included domestic hard butters containing some trans fatty acids. Often, these are needed both for their higher melt points and increased stability, especially in the presence of sensitive nutraceuticals. As consumer awareness of saturated fats and trans fatty acids has increased, fat manufacturers have been able to provide alternate processing techniques to control trans-fatty acid content.

Chocolate and compound coating differ greatly in preparation for application to the final product. Chocolate contains cocoa butter, which is polymorphic in nature. Cocoa butter requires tempering to obtain the stable form V (or beta) crystal form to maintain the proper gloss and snap of a good coating. To properly temper it, the chocolate mass must be cooled below its setting point, then rewarmed to a temperature higher than the melting point of the unstable beta-prime crystals, but lower than the melting point of the stable beta crystals. This is 88º to 90ºF for milk chocolate (because of the milk protein) and 90º to 92ºF for semi-sweet chocolate. The stable seed crystals are allowed to grow and mature, producing a more stable, compact structure that gives the best gloss and shelf life. Compound coatings, on the other hand, are simply cooled to 5º to 10ºF above the melting point of the coating.

Regardless of their manufacture, couverture chocolates and coatings are generally applied onto a center in one of three general ways:

Enrobing. This is the least-expensive method, and the one often used for baked goods and nutritional bars. Centers are carried on a wire mesh through an enrober that coats them under a curtain of chocolate and/or floats them through a pool to coat the bottoms. An air curtain controls weight; if desired, a pattern can be applied through use of a stringer.

Panning. Chocolate is sprayed on the centers as the centers rotate in revolving pans, then cool air is blown in the pans to harden the chocolates.

Dipping. This process — generally done by hand by small-scale producers — consists of many intricate steps, making it more expensive than other methods.

Flavoring a compound coating to taste like a chocolate is often a challenge, due to differences in fats and in the solids ingredients. According to Julie Snarski, manager of applications and product development, David Michael & Co., Philadelphia: “Chocolate enhancers have recently been developed to allow coating manufacturers to produce compound coatings which taste like a milk chocolate or a dark chocolate. Because compound coatings are not standardized products, we work with the specific customer to optimize their formulations. Fortified chocolates are also a technical challenge in that the ingredients often mask flavors or leave a bitter aftertaste.” Increased flavoring is sometimes required to overcome the flavors of nutraceutical components in a bar’s base, or nutraceutical components or proteins may be included in the coating itself. Manufacturers of many of the earlier nutritional bars tended to heavily flavor the compound coating to mask protein flavors in the base itself, but some of the more recent bars on the market have moved toward other processing technologies to lighten the off-flavor impact of nutraceuticals.

A sweet sugar-free marketFor centuries, the primary sweetener in chocolates and compound coatings has been sugar. However, sugar-free chocolates and couvertures — though still only a small percentage of total production — is one of the most rapidly growing areas in the marketplace. This increase has continued for several reasons: a rise in rates of obesity and type 2 diabetes; technological improvements in sugar-free bulking agents to replace the functionality of sucrose, and continuing improvement in formulations that result in better-tasting sugar-free confections; and dietary needs and/or low glycemic awareness.

The sugar alcohols, or polyols, most often considered when designing sugar-free compound coatings are maltitol, mannitol, xylitol, lactitol, isomalt and erythritol. Mannitol was used in most of the original formulations 10 to 20 years ago, but was eliminated from most general use due to its high cooling effect and laxation potential. Its replacement, crystalline maltitol, is a disaccharide polyol with many physical and chemical characteristics similar to sucrose. Maltitol is noncariogenic, has 2.1 kcal/gram (versus 4.0 kcal/gram for sucrose) and has 90% of the sweetness of sucrose. Maltitol has worked extremely well in chocolate and compound-coating applications — both in chocolate-confection applications and in enrobed products, such as nutritional bars. When replacing sucrose in a chocolate formulation, several points require consideration:

Moisture. A chocolate system is fat-based, and any moisture contributes to variable viscosity problems and problems in remelting.

Hygroscopicity. The coating manufacturer does not want an ingredient that has the potential to pick up any moisture.

Heat of solution (cooling effect). For the most part, the consumer expects a cooling sensation from a chewing gum, not a chocolate.

Solubility. Any sucrose replacer that does not solubilize rapidly in the mouth tastes like chalk.

Melting point. Sucrose replacers that melt in-process form glasses, which can lead to texture problems.

Laxation. Developers should remember that the lower the potential of laxation, the better.

Form. Is the product crystalline, anhydrous, a monohydrate or a dehydrate? What form does it want to take? Processing usually helps it achieve these goals.

Cost-effectiveness and/or availability. Nothing is as cost-effective as sucrose, but availability is a good characteristic, as well.

Until the recent boom in sugar-free chewing gum, chocolates, cookies and nutritional bars, crystalline maltitol fulfilled many of these criteria nicely. Availability has become an issue, but, according to Peter Jamieson, research technologist, SPI Polyols, Inc., New Castle, DE: “The industry has responded as well as possible to the needs of coating manufacturers. We are suggesting that coating manufacturers take a broader look at how to replace maltitol in their sugar-free applications while we look at ways to continue to meet crystalline-maltitol demands. We have been successful in extending maltitol with either mannitol and/or our spray-dried hydrogenated starch hydrolysate powder (HSH). Use of the HSH not only mediates the cooling effect of mannitol, but it also mediates laxation potential, as well (powdered HSH has very little potential for laxation).” This very soluble and nonhygroscopic sweetener has excellent availability.

Many high-protein bars on the market often include more than sweeteners and fat in the coating. It is not uncommon to find a higher-than-normal level of dairy or soy proteins in the coating, as well as in the bar. In these, the coating manufacturer needs to balance moisture and sweetness to obtain the best product with reasonable remelting and enrobing characteristics.

Much of the sugar-free compound coating on the market enrobes other products, such as nutritional bars — a market that continues to grow at a rapid pace. The sugar-free confection market, led by the success of Kansas City, MO-based Russell Stover Candies Inc. (a 20.8% increase in sales over 52 weeks ending Oct. 22, 2002, according to Chicago-based Information Resources Inc. data), has also spurred a need for the development of centers for these confections — caramels, liquids, fondants, etc. The baked-goods and ice cream categories have created a need for sugar-free chocolate chips and inclusions — many of which are maltitol-based. From all indications, the sugar-free inclusion market is starting to grow, possibly heralding further growth for 2003 in the no-sugar-added ice cream and baked-goods markets.

Chocolate — a health food?More and more research is being reported about the positive effects of chocolate, and researchers are re-examining previously reported negatives. Chocolate, for example, is very rarely observed to cause an allergic reaction by itself. However, chocolate candy may often contain ingredients that cause allergic reactions, such as milk, soy lecithin, gluten, peanuts and tree nuts. So, unless a production line is dedicated to one product, there is a significant possibility for cross-contamination from other products. Many recalls over the past few years can be attributed to this. Processors must be careful to identify potential cross-contamination lines; manufacturers are required to place a warning label on products made on these lines.

Perhaps the best news for chocolate is the presence of cocoa polyphones. Studies indicate that the darker the chocolate, the higher the level of flavonols, such as procyanidins, catechins and epicatechins — all identified in lowering the risk of type 2 diabetes, asthma, heart disease, and lung and prostate cancer. While many studies have reported the antioxidant benefits of red wine, fruits and vegetables — even beer — chocolate offers even more significant benefits than these products. A 40-gram milk-chocolate bar contains 205 to 300 mg of polyphenols, equivalent to a 5-oz. glass of red wine. Ongoing human studies at The Pennsylvania State University, University Park, have shown that consumption of cocoa powder and dark chocolate significantly improves cholesterol ratios, with a higher ratio of high-density lipoproteins to low-density lipoproteins, resulting in a lowered risk for heart disease. Research completed at the University of Scranton, Scranton, PA, has shown that the quality and amount of antioxidants in chocolate products far exceeds that found in black tea, red wine, raisins and other plant products. Cocoa powder ranks highest in antioxidant content, followed by dark chocolate and milk chocolate.

Raymond C. Glowaky, Ph.D., senior vice president of scientific affairs, CMA, adds that the American Cocoa Research Institute, Vienna, VA, has funded these and several other studies over the past four years. He also notes that 40 years of research has shown that cocoa butter does not raise blood-cholesterol levels, potentially due to its high stearic-acid content. The major fatty acids in cocoa butter are stearic acid (35%), oleic acid (35%), palmitic acid (25%) and linoleic acid (3%). Diabetics may also take heart that, because of the amount of fat in chocolate, small amounts of chocolate do not have a negative effect on postprandial blood sugar. In other words, the glycemic index of chocolate is relatively low.

Organic chocolate is another growing market. According to CMA, the demand for organic chocolate has increased during the 1990s and the beginning of the 21st century. Annual market growth during the last three years reached 10% to 15%. Very small companies that sold their products primarily in health-food stores or specialty shops first produced certified-organic chocolate. Now, supermarkets also sell these organic chocolates, but relatively few chocolate manufacturers still dominate this market.

A tight link exists between chocolate and compound coatings and a number of rapidly growing markets, including chocolate confections, nutritional and sports-market bars, baked goods, ice cream, and frozen desserts. These sectors are driving the rapid growth of chocolate and coating manufacture, even though the chocolate-bar market is increasing at a relatively slow rate. As the population ages, and diets continue to revolve around carbohydrate content, the demand for sugar-free and no-sugar-added chocolates and coatings will also expand. As older consumers seek out ingredients for a healthful lifestyle, these ingredients will also to change the future of this industry. Learning from fat-free’s rise and decline, manufacturers continue to formulate for better-tasting products with a process that, if continued, should ensure a sweet future for the chocolate and compound-coatings markets.

Ronald C. Deis, Ph.D., is the director, product and process development at SPI Polyols, Inc., New Castle, DE. Deis has 20 years of experience in the food industry, both in food ingredients (starches, polyols, high potency sweeteners, bulking agents) and in consumer-product companies (cookies, crackers, soups, sauces). He has been a short-course speaker (polyols, fat replacers) and a freelance writer on a number of food-science-related subjects in food journals, and has contributed chapters on sweeteners and fat replacers for several books.

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