Alkalized Cocoa Powders Bill Dyer Blommer Company

ocoa powder has gained a significant ever, a variety of new applications, particu- Camount of attention in the industry, larly in the dairy and bakery industries, and not only because of its volatile price, but increased consumption in developing coun- also because of the increase in the con- tries have increased demand for cocoa pow- sumption of cocoa powder in non-confec- der. There have been several other factors tionery applications (i.e., dairy and bakery in the last two years that have contributed segments). Because of this growth in use, it to a shortage of supply and increase in cost is important to understand the uses and of cocoa powder. For instance, the use of applications of various powders.This paper equivalents and pgpr (a vis- gives an overview of cocoa powder as it cosity-reducing emulsifier) has reduced the applies to its process and application; iden- demand for cocoa butter, thus reducing the tifies the types of cocoa based on the alka- cocoa butter/cocoa powder production, and lization process; determines its flexibility outsourcing by large manufacturers that and limitations in a given application; and were once large producers of cocoa butter shows how to select a cocoa powder for a and cocoa has taken some manufac- specific application. turing capacity off line. An increase in demand for cocoa powder coupled with sta- WHAT IS COCOA POWDER? tic demand for cocoa butter has created a Dyer is the director of The FDA defines cocoa powder as the global shortage of quality cocoa powders technical sales and food prepared by pulverizing the mater- and soaring prices. This cocoa supply issue service at Blommer Chocolate Company. ial remaining after part of the cocoa will remain until the demand for cocoa pow- He joined the company has been removed from ground cocoa nibs. der is rationalized in line with the relative in 1996. It is the product obtained by grinding the demand for cocoa butter. Dyer previously worked solids remaining after cocoa butter has Like any other ingredient, cocoa pow- at Loders Croklaan, been pressed out of . This ders have a specific role in food applications. Durkee Industrial Foods, separation of and cocoa but- They are expected to deliver flavor and color and Gill and Duffus Products. ter is achieved typically through hydraulic while not imparting any negative attributes. pressing. Chocolate liquor contains about Not all cocoa powders are the same and no 54 percent cocoa butter; after pressing, one cocoa powder meets the requirements cocoa solids will have about 10–12 per- for all applications.This means one needs to cent cocoa butter. have a very clear understanding of whether Cocoa powder evolved in the chocolate a cocoa can or cannot perform its functions industry as a by-product. The original pur- in a given application. pose of pressing chocolate liquor was to obtain cocoa butter, which is utilized in the COCOA POWDER PRODUCTION manufacture of chocolate coatings. How- In order to learn about and understand dif- Bill Dyer ➤

128 57th PMCA Production Conference, 2003 Alkalized Cocoa Powders ferent types of cocoas and how they can This knowledge is a very helpful tool An increase in be used in various applications, we need to predict a flavor profile in powders demand for cocoa to start with a brief overview of the cocoa based on a type of bean or a blend of sev- powder coupled process, from selection of beans through eral beans. Problems can arise due to vari- with static demand alkalization. With this in mind, three sub- able climate conditions during a given for cocoa butter jects will be discussed briefly: cocoa beans, year, changing the profile for a given ori- has created soaring roasting process and types of roasters. gin. Political instability can affect the prices and a global More time will be spent on alkalization availabilities of specific types of beans in shortage of quality processes and cocoa applications. specific quantities at times. These unpre- The following terminologies will be used dictable variables have prompted the cocoa powders. frequently in the rest of this paper: industry to put more emphasis on pro- • Nib — Shell-free pieces. cessing, specifically roasting and alka- • Chocolate liquor — Paste resulting from lization, which are the two key process- grinding nibs. ing steps that can assure quality and • Press cake — Cocoa solids remaining in the press pot after part of the cocoa but- maintain quality consistently. ter has been removed by hydraulic press (the fat content is generally 10 percent Roasting to 12 percent). In general, there are three ways to roast • Kibbled press cake — Pieces of crushed cocoa beans or cocoa nibs. press cake after they are removed from Fluid bed roasters are designed for bean the press. roasting. In these roasters cocoa beans are • Alkalization — A process where nibs, in constant motion from hot air on an oscil- chocolate liquor or crushed press cake (coarse cocoa powder) is treated with a lating conveyor. These roasters are com- suitable alkali solution and, subsequent monly used for large-volume operations to alkali treatment, the moisture is where the objective is to roast one or two removed during drying and/or the roast- types of beans. ing process. Cocoa powders derived The second category of roaster is the from these processing options are static bed roaster where a bed of beans or referred to as nib-alkalized cocoa, liquor- alkalized cocoa or cake-alkalized cocoa. nibs is conveyed horizontally or vertically Cake-alkalized cocoa is also referred to through various heating and cooling zones. as powder-alkalized cocoa. There are two types of static bed roasters. • Cake alkalization/powder alkalization — In the first type, a bed of nibs or wet nibs refers to the alkalization process where (after alkalization) travels horizontally crushed cocoa press cake is treated with through several zones where the wet nibs a suitable alkali solution. are first dried, then roasted and finally Beans cooled. This type is more practical in the The making of cocoa powder is a many- nib alkalization process because this step process that begins with the bean. roaster can be used not only for roasting, Each step at each stage of cocoa powder but drying as well. production can have a large impact on the Flavor Notes of Cocoa Beans final powder product application. In “The Origin Typical Flavor Profile Application of Cocoa Powders in Choco- Indonesia Bitter to acrid late Confectionery,” Hans Kattenberg very Malaysia & New Guinea Acid to astringent clearly shows the correlation between West Africa Rich cocoa flavor beans from various origins and their char- Ecuador Floral/perfumy acteristic flavor notes (Figure 1). Figure 1 ➤

57th PMCA Production Conference, 2003 129 Alkalized Cocoa Powders

By controlling the The second type of static bed roaster is limited to the types of cocoa beans avail- degree of more suited to cocoa beans and not nibs. able for blending and to the type of cocoa alkalization, the The beans travel vertically through sev- bean roasters. Conversely, there are many types of alkali eral heat zones. Roasting is achieved by types of alkalized cocoa powders. By con- applied, the cocoa forcing heated air through the bed of beans trolling the degree of alkalization, the types as it travels through each zone. With this of alkali applied, the cocoa bean types and bean types and at roaster, there are options to sterilize the at which stage of the cocoa process the alka- which stage of the beans with a pressure cooker-type system lization takes place, a whole spectrum of cocoa process the prior to roasting.This approach allows one alkalized cocoa powders can be produced. alkalization takes to obtain liquors and powders free of place, a whole spore-forming bacteria. ALKALIZATION spectrum of The third roasting method utilizes the The alkalization process has been well doc- alkalized cocoa rotary drum. Rotary drum roasters are umented by Mike Kostic. In “Cocoa Alka- powders can be used in nib roasting and are the most lization” he covers in detail the types of produced. widely used form of roasters.They are also alkali and the types of alkalizing methods. used in the nib alkalization process.After The purpose of alkalization is threefold: the alkalization treatment, wet nibs are • To neutralize the acidity of the cocoa beans dried and roasted in drum roasters. Hot and remove astringent cocoa flavor. air is blown into a rotary drum, causing • To promote reaction between cocoa pig- maximum exposure of nibs to heat. Uti- ment and alkali in the presence of oxy- lizing this method, process parameters can gen and heat to develop colors ranging be customized to achieve a range of fla- from light brown to red, and in some cases very dark colors. vors and colors for natural cocoa powders • To promote flavor development by pro- (nonalkalized cocoa powders). moting reaction between and reducible sugars present in the cocoa Powders beans. Cocoa powders are categorized based on Alkalized cocoa powders can be obtained two factors. First, cocoa powders are cate- by using any one of these approaches: gorized by the percent of cocoa butter in liquor alkalization, powder alkalization or the powder. Powders with 10 to 12 percent nib alkalization. Each process results in cocoa butter are referred to as low fat certain advantages and disadvantages. cocoas. Fat contents of 16 to 18 percent are called medium fat cocoa. Fat contents Liquor Alkalization of 22 to 24 percent are called breakfast Liquor alkalization is ideal to get mild-fla- cocoa or high fat cocoa. vored alkalized cocoa powders. However, Secondly, cocoa powders are further dif- the process is limited to the amount of mois- ferentiated based on whether or not pow- ture that can be added during alkali treat- ders were processed with alkali at the nib, ment. The ideal amount of water required liquor or cake stages. Powders not processed to promote optimum reaction during alkali with alkali are referred to as cocoa or nat- treatment is not possible with liquor because ural cocoa, and alkalized cocoas are referred water and cocoa butter are not miscible and to as simply cocoa processed with alkali or there is a potential for degradation of the . cocoa butter, also leading to viscosity issues Today, 95 percent of the powders used in in the finishing of the process. Limited the food industry are low fat. Natural cocoa amounts of water added to liquor to pro- powder varieties are few because they are mote alkali treatment will yield a narrow ➤

130 57th PMCA Production Conference, 2003 Alkalized Cocoa Powders range of color and flavor profiles. Similar Nib Alkalization There is less to nib-alkalized cocoa, there is added cost Nib alkalization provides the best option. detrimental impact with this method of production since the There is less detrimental impact on the on the composition cocoa butter obtained from this process composition of nibs during alkalization of nibs during requires deodorization. because the components of the nibs are alkalization still in their natural state. By contrast, in because the Powder Alkalization or Cake chocolate liquor alkalization, all of the Alkalization components of the cocoa butter is released and nonfat com- Powder alkalization is a less sophisticated nibs are still in ponents are in emulsion phase, making the process requiring a basic reacting vessel their natural state. alkalization less effective.A stronger alkali with heat and vacuum capabilities. In this treatment to liquor can lead to detrimen- process press cake is crushed to a coarse tal effects on cocoa butter. The powder is powder prior to treatment with a suitable even more sensitive to alkalization. In pow- alkali solution. It is a cost-effective option ders, the nonfat components, specifically because, unlike nib or liquor alkalization, and starch, are concentrated the cocoa butter is not factored into the cost because the fat is removed and they are of cake-alkalized cocoa. However, the color subjected to a maximum exposure as a and flavor attributes of cake-alkalized pow- result of particle size reduction from grind- ders are limited. Powder alkalization is use- ing into powder. Given the physical and ful in making very dark cocoa powders chemical state of starting material for alka- where flavor is not a criterion. Cocoa pow- lization, it should not be surprising to us ders consist of 19 to 20 percent protein and that nib alkalization offers the best results 10 to 15 percent starch.The increased sur- for color and flavor attributes in cocoa. face area in the powder to be alkalized Another benefit of nib alkalization is that exposes these proteins and starches to heat during this process spore-forming thermo- and moisture. As a result, during the dry- phylic and mesophylic bacteria are greatly ing process protein is denatured, giving reduced. The reduction of these bacteria is unfavorable textural effects in dairy and in especially beneficial to the dairy industry as some confectionery applications. Starches the presence of spore formers in dairy prod- go through irreversible chemical modifica- ucts, such as cocoa-flavored milk beverages, tions due to heat and hydration and as a can shorten the shelf life drastically. result are jellified. Chemical and physical The disadvantage of nib alkalization is changes of proteins and starches during that powders derived from this process are powder alkalization also have an impact on expensive. Every pound of nib-alkalized grinding capabilities of batches after the cocoa results in one pound of cocoa butter, alkalization process. It is difficult to grind and cocoa butter pressed from nib-alka- alkalized cocoa cake to achieve a fineness of lized liquor must be deodorized, which is 99.5 percent through 200 US mesh, which is an added manufacturing cost. the industry standard. Grinding through- Cocoa butter has the highest commod- put rates drop significantly in order to ity value in the butter/powder equation, achieve a good fineness. The impact on therefore the cost of the powder is dictated grinding also relates to the degree of alka- by the cost of cocoa butter involved in nib lization; the higher the degree of alkalization alkalization (Figure 2). Also, nib alkaliza- in the cocoa, the greater the decrease in tion is more capital intensive, adding to grinding throughput rates. manufacturing complexity and cost. ➤

57th PMCA Production Conference, 2003 131 Alkalized Cocoa Powders

Another benefit of MATRIX OF PH VERSUS COLOR IN 75 percent water) is measured by a Hunter- nib alkalization is COCOA POWDERSXXXXXXXXXXXX Lab colorimeter. that during this As we discussed, the objective of alkaliza- APPLICATIONS process spore- tion is to neutralize the acidity and promote Cocoa powders are used in a wide range of forming the color development in cocoa powders. There is a close correlation between color applications in the food industry. It is the thermophylic and and pH of cocoa powders. Powders with only ingredient that remains as a by-prod- mesophylic light brown colors have a pH of 6.5 to 7.0 uct in a chocolate plant where chocolate bacteria are greatly and the pH of darker and red powders liquor is pressed and yet it is an ingredi- reduced. ranges from 7.0 to 8.0. Very dark powders ent that is in great demand in the bakery, such as black can have a pH of up to 8.2. dairy and beverage industries. This is seen in Figure 3 where the color of cocoa paste (25 percent cocoa powder, Color of Cocoa Powders in Applications Before we discuss the applications, we need Cocoa Butter/Powder Prices to address the unique property of colors

3.00 $4,500 seen in cocoa powders.The colors of cocoa

$4,250 2.75 $4,000 powders in a given application can be 2.50 $3,750 defined similar to food colors, i.e., lakes 2.25 $3,500

$3,250 2.00 (which are dyes plated on a carrier), or $3,000 1.75 $2,750 dyes (which are water-soluble pigments). 1.50 $2,500

$2,250 1.25 The visual perception of powder colors $2,000 1.00 $1,750 and applications of powders in oil-based Futures Price 0.75 $1,500

$1,250 or anhydrous products are analogous to 0.50 Butter & Cake Ratios $1,000 0.25 lakes except cocoa powder’s visual appear- $750

0.00 $500 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 ance is more complex. The powder color 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 Butter Ratio Cake Ratio Futures Price can vary depending on the cocoa butter as Figure 2 well as the orientation of the cocoa butter crystals in the powder. During shelf life, due to fluctuations of temperature, the Cocoa Powders — pH versus Color cocoa butter crystals will melt and recrys- tallize, but never in the original orienta- BLACK B A tion, and the crystals may even shift to the DARK L surface of the cocoa particle.This constant DUTCH PH shift in fat crystals changes the appearance RED of powders, resulting in different color per- DUTCH ception of the same powder, and is often mistaken for color degradation or for a DUTCH deviation in color control from the speci- fication.The higher the fat content in pow- NATURAL der, the greater the changes in visual per- 051015 20 25 ception. While the visual appearance of the powder may be alarming, due to cocoa The L value is indicative of darkness, the A value is indica- tive of red color and the B value is indicative of brown butter bloom, it will not affect the prod- color in cocoa powders uct application. Figure 3 In a water-based application, the pig- ➤

132 57th PMCA Production Conference, 2003 Alkalized Cocoa Powders ments are dissolved like dyes and the per- Particle Size Relationship to Due to the higher ception of color is different.Two powders Application flavor and color may look similar in their raw form before The industry standard for fineness of intensity of alkalized being placed in an application, but appear cocoa powders is a minimum of 99.5 per- cocoa powders, a differently in a water-based application. cent through a US 200 mesh, which means reduction in the Conversely, two powders may appear dif- 99.5 percent of the particles must be amount of powder ferent in their raw form and yet result as under 74 microns.The fineness is less crit- can be achieved in similar colors in application. In Figure 4 ical in baked goods and compound coat- compound formulas. the three powders appear to be different in ings. Fineness is less detectible in baked color, and the color measured by Hunter- goods; in compound coatings a further Lab agrees with visual perception. These particle size reduction is done during the three cocoa powders are the same but they refining process.The most critical role of were exposed to different temperatures cocoa particles is in water-based applica- over time, resulting in a change in the tions such as icings, toppings, syrups, pud- visual color. dings, fillings, nougats, aerated creams and Typical cocoa powder flavors and their truffles. In these applications, cocoa par- applications can be seen in Figure 5. ticles will swell due to hydration leading In bakery, dairy, beverage and other to a perception of coarse texture. The water-containing product applications there degree of swelling of particles depends is enough water for colors to leach out of Powder Color at Various Temperatures cocoa particles to deliver the appealing col- ors in the finished product. In confectionery applications such as confectionery coatings, meltaways, oil- or fat-based fillings and in some truffles, water-soluble colors do not play a role because they cannot deliver col- ors in oil phase. But what is perceived is the color of the cocoa itself. There are no oil-soluble pigments in the cocoa bean and if they are present in trace amounts, they are removed along with cocoa butter dur- ing pressing.

Compound Coatings In compound coatings, the benefits of nib- alkalized cocoa powders are very easily Figure 4 assessed. Due to the higher flavor and color intensity of alkalized cocoa powders, a Cocoa Powders — Typical Flavors and Applications reduction in the amount of powder can be Type of Cocoa Typical Flavor Common Applications achieved in compound formulas (Figure 6). Natural—nonalkalized Milk, cocoay notes Compounds, syrups, bakery toppings, confectionery The graph in Figure 7 shows the sensory Alkalized—light dutch Mild, cocoay notes with mild Dairy, beverage, creams, assessment of the two products referred alkali undertones syrups, toppings, confectionery Alkalized—red Moderate to strong alkali Bakery, dairy, beverage, to in Figure 6.The compound coating with notes creams, confectionery alkalized cocoa at a lower application level Alkalized—dark Milk to moderate alkali notes Bakery, confectionery functions similar to natural cocoa without Alkalized—black Intensely unique alkali flavors Cookies, coloring agent compromising color and flavor attributes. Figure 5 ➤

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The most critical on several factors in various cocoa pow- Denatured proteins and jellified starches role of cocoa der applications: may behave differently compared to the particles is in • Type of alkalized cocoa powder same components found in nib-alkalized water-based • The amount of water in the formula cocoa powders. applications. In • Processing heat In an attempt to demonstrate this behav- • Time line from process to consumption ior two test models were selected. In the these applications, (aging process and shelf life) first model (Figure 8) samples of cocoa cocoa particles will Powder-alkalized cocoa powders respond powder and water suspension (1 part cocoa swell due to to heat and hydration differently compared and 10 parts water) were stored at 65°C hydration leading to nib-alkalized cocoa powders. This dif- for 24 hours to simulate an accelerated to a perception of ference could be due to the state of pro- shelf-life condition. Samples were collected coarse texture. teins and starches in the cocoa powder. from the top, middle and bottom of each suspension. Compared to the particle size Compound Coatings — Natural Versus Alkalized of dry powders We see an increase in the population of large particles. Compound Coating with Compound Coating with In the second model, a filling was made Natural Cocoa Powder Alkalized Cocoa Powder with the same cocoa powders as before Sugar 33.8% Sugar 33.8% Fractionated palm kernel oil 31.0% Lactose 4.0% but using the formula in Figure 9. Natural cocoa 8.0% Fractionated palm kernel oil 31.0% Corn syrup, condensed milk and cocoa Skim milk 23.8% Cake-alkalized cocoa 2.0% powder blends were stored at 65°C for 0.3% Nib-alkalized cocoa 2.0% Salt 0.08% Skim milk 23.8% 24 hours to simulate an accelerated shelf Vanillin 0.02% Lecithin 0.3% life condition. Artificial flavor 0.02% Salt 0.08% Sensory (Figure 10) and particle size analy- Vanillin 0.02% sis of the fillings show that cake- or powder- Artificial flavor 0.02% alkalized cocoa powders result in a grittiness Figure 6 as a result of swelling of the particle. Flavor Profile of Compound Coatings Natural versus Alkalized Cocoa PH of Cocoa Powders in Applications Although the neutralizing of acids in cocoa Cocoa powders does have flavor benefits, a higher degree of alkalization can result in per- formance problems. Following are some Alkalized Sweet of the critical factors related to applica- tions and pH of cocoa powders: In baked goods, especially in products Caramel where leavening agents are used, higher Natural Alkalized pH cocoa powders will interfere with leav- Figure 7 ening agents, causing larger air bubbles in cake and overspreading of cookies. Particle Size Analysis of Nib- and Cake-Alkalized Cocoa In puddings and pie fillings, excess free Dry Particle Size 20 grams of cocoa in 200 ml of water alkali in cocoa powders interfere with at 160°F incubated for 24 hours jelling mechanisms of starch molecules Nib Cake Nib Cake Top Mid Bottom Top Mid Bottom and, as a result, end products either take a <74 microns 100 100 99.79 99.50 99.25 98.53 96.62 96.44 long time or fail to thicken. <44 microns 99.92 100 98.02 97.32 96.81 96.19 91.60 91.46 In chocolate syrups and toppings, pH of Figure 8 the finished product is targeted to be in ➤

134 57th PMCA Production Conference, 2003 Alkalized Cocoa Powders the range of 4.0 to 4.5 because at this range For water-based applications, cocoa pow- Although the preservatives such as sorbate ders may be evaluated in milk. A simple neutralizing of acids are more effective. Therefore a blend of and quick method is to suspend 2 g of in cocoa powders natural and lightly alkalized cocoa pow- cocoa and 2 g of sugar in 100 ml of warm does have flavor ders is ideal in such applications. The low fat milk (100°–110°F). Milk provides a benefits, a higher improper selection of cocoa powders can white hue, which aids in seeing subtle dif- degree of often result in a change of viscosity due to ferences in color, and its slight sweetness alkalization can particle swelling. will aid in identifying differences in flavors result in performance or unacceptable flavors. SUMMARY Talk to your cocoa supplier to learn problems. We are certain that there is a difference more about cocoa processing. ■ between nib-alkalized cocoa powders and powder-alkalized cocoa powders in milling REFERENCES powders, in flavor and color, and also in Chocolate and Cocoa Edited by Ian Knight. Blackwell Science Ltd., 1999. water-based applications. We are also cer- Kattenberg, Hans R. Manufacturing Confec- tain that the cocoa bean contains high tioner, 1995. amounts of protein and starch, and that pro- Kostic, Michael J. Manufacturing Confectioner, tein and starch are sensitive to heat and 1997. Meursing, E.H. Manufacturing Confectioner, hydration. However, there is no research 1980. evidence to confirm the relationship Trout, Richard. Manufacturing Confectioner, between the application responses of alka- 2000. lized cocoa powders and the state of pro- teins and starches. We are not certain Confectionery Filling whether modification of proteins and Corn syrup 8.0% starches in powder-alkalized cocoa powders Condensed milk 35.26% leads to difficulties in milling cocoa pow- Fondant 34.78% ders and swelling of particles in response to Coconut oil 14% Cocoa 7.5% heat and hydration in applications. Lecithin 0.1% Given the information on how cocoa Salt 0.11% was processed, one can make a prudent Vanillin 0.11% assessment on how best to use this pow- Artificial flavor 0.14% der in a specific application. Figure 9

Application Suggestions: Identify the application objectives and Flavor Profile of Confectionery determine if the application is water-based Fillings — Cake-Alkalized versus Nib- Alkalized Cocoa or fat-based. In fat-based applications powders should Alkalized be selected based on color assessment using a protocol that is consistent.A quick Graininess Cocoa method to assess the color in cocoa is to place 10–20 g of samples to be tested along with a color standard in a 95°F hot cabi- net for 30 minutes and visually evaluate "Fudgy" Sweet colors or measure color by using a col- Cake Alk. Nib Alk. orimeter. Figure 10

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