WWW.AGRIMOON.COM Lesson 42 CHOCOLATE LIQUOR, COCOA BUTTER AND COCOA BUTTER REPLACERS/EXTENDERS 42.1 Introduction In the previous lesson we learnt about the cocoa bean varieties and some preliminary cocoa bean processing methods. Herein processing of cocoa beans into several products like chocolate liquor, cocoa powder, cocoa butter, etc. will be dealt. 42.2 Processing of Cocoa Bean 42.2.1 Roasting 42.2.1.1 Objectives of Roasting v Reduction of moisture v Release of the beans from the shell v Develop chocolate flavour v Changes the colour of the beans (nibs) affecting the appearance of the finished chocolate. 42.2.1.2 Batch or Continuous roasters may be used: § Hot air treatment § Saturated steam treatment § Infra-red treatment Depending on the bean type, the beans are heated to 110-220oC. Temperatures from 70-200oC are reported depending on machine, and also on the use that will be made of the beans. Certain type of milk chocolate requires beans with a very mild roasting. When pressing process is involved, a high roast is used to: (i) obtain sufficient reduction in bacteria count, and (ii) good reduction in thermo-resistant spores. Prior to roasting, beans may taste astringent, bitter, acid, musty, unclean, nutty or even chocolate-like. Roasting reduces the acidity; significantly decreases the concentration of volatile acids (especially acetic acid) reducing the acidic taste. Roasted beans possess typical intense aroma of cocoa. 237 FOOD TECHNOLOGY – I a) Flavour generation Maillard browning forms glucosylamines or fructosylamines Other compounds formed include pyrazines, pyrroles, pyridines, imidazoles, thiazoles andoxazoles. The pyrazine content of certain cocoa bean types is mentioned in Table 42.1. Table 42.1. Concentration of pyrazines depending on the cocoa bean utilized Cocoa bean type Concentration of pyrazines Ghanaian roasted beans 698 mg/100g beans Tobasco beans (Mexico) 142 mg/100g beans Production of aldehydes from amino acids plays an important role in flavour balance of final chocolate; generation of carbonyls also takes place. 42.2.1.3 Roasting methods Some of the methods used for roasting of cocoa beans are detailed hereunder. i) Bean roasting This involves roasting of whole cocoa beans. a) Advantage Loosens the shell making it easier to remove. b) Disadvantages i. Shells from raw cocoa beans contain in dry state about 2% fat vs. 5-6% in roasted beans. ii. Combustion gases produced foreign materials on shell which is detrimental to flavour of cocoa mass. iii. Energy is lost when the shell is removed. ii) Nib roasting a) Advantage i. Particles roasted are of more uniform size. ii. Poorer cocoas can be upgraded by use of reducing sugar solutions or other treatments during roasting. 238 WWW.AGRIMOON.COM b) Disadvantage It is necessary to remove the shell from unroasted beans. iii) Mass roasting It is done continuously in thin-layer columns; need to have particles of a uniform size to obtain uniform heating. Heating can be done in scraped surface heat exchanger. a) Advantages i. Uniformity of heat treatment is ensured. ii. Bacteria on shell gets inactivated; lower initial bacterial count; better microbiological status. The moisture content is critical for the roasting procedure, which must not be started when the beans have < 2.5% moisture, otherwise poor flavour develops. 42.3 Grinding The cocoa nib consists of 55% cocoa butter and 45% solid material coming from plant cells; the latter is ground finely. When eating chocolate or drinking chocolate milk, no grittiness should be felt in the mouth. In cocoa powder/chocolate, we desire a narrow particle size distribution. Grinding confers the following advantages: Ø Facilitates pressing operation. Ø Improves the rheological properties of chocolate. Several grinding steps are followed; desired fineness is 15-70 um. Pre-grinding is carried out with Disc mills, hammer mill, pin mill. Ultimate fineness is achieved with Triple stone mill, Vertical ball mills (attrittors). In chocolate industry, roller mills with five rolls are most commonly used for refining the mass; used to grind chocolate mass, after adding preground sugar and milk powder. 42.4 Types of cocoa mass Cocoa mass may be used for the production of: (a) Chocolate or (b) For pressing i.e. production of cocoa butter and cocoa powder. The mass for processing is already alkalized. 239 FOOD TECHNOLOGY – I Cocoa powder is either alkalized or non-alkalized. Alkalized cocoa powder contains potassium carbonate, sodium carbonate, sodium hydroxide or magnesium, all of which neutralizes the naturally occurring acids and make the powder easier to dissolve in liquids. Cocoa powder may also contain added starch (i.e. corn starch) to keep it free from caking during storage. Unsweetened cocoa powder is used primarily in baking. Sweetened cocoa powder is often mixed with hot milk or water to product „hot chocolate‟ or „hot cocoa‟. 42.5 Quality criteria for cocoa mass The quality parameters for cocoa mass is presented in Table 42.2. Table 42.2 Quality criteria for cocoa mass Parameters Value Fat 50-58 Moisture Max. 2.50 pH 5.2-6.0 Shell content, % Max. 1.75 Total bacteria Max. 10,000/g Moulds Max. 50/g Yeasts Max. 50/g Enterobacteria/g Negative E. coli/g Negative Salmonella/25 g Negative 42.6 Cocoa Powder After roasting and winnowing (removing the outer shell from the cocoa beans) they are ground making cocoa liquor. The heat which is generated melts the cocoa fat thus generating a liquor, and sometimes additional heating is employed. The liquor hardens to unsweetened chocolate when it cools below 35 oC. Pressure is employed to the cocoa liquid (while slightly heated) to remove some of the fat which is referred to as cocoa butter. The remaining cocoa solids contain 10-25% cocoa butter. The solids are then ground to cocoa powder. 240 WWW.AGRIMOON.COM Sometimes the cocoa is made alkaline by treatment with potassium carbonate; this is called „Dutched cocoa ‟. This gives a darker color and a stronger flavor. 42.6.1 Production of Cocoa powder The press cakes are ground to powder, which is packed after complete cooling. The alkalizing process can be used to create many types of cocoa powder with differing colours. 42.6.1.1 Alkalizing: It was developed in the 19th century in Holland and hence often referred to as „Dutching‟ process. Cocoa nib (less frequently cocoa mass, cake or powder) is treated with an alkaline solution. The process is executed by adding a solution of an alkali (mostly potassium carbonate/potash) to the cocoa; legal maximum being 3% potash calculated on nib. The process improves the quality of cocoa powder in two ways: v It results in a milder taste – mainly the result of the neutralization of the light acidity of fermented cocoa beans. v It makes the colour darker. Careful control of reactions can lead to different shades of colour – Orange, red, brown and even black. The specific colour is reached by choice of reaction conditions such as temperature, time, amount and concentration of the alkaline solution. A light alkalization might improve the flavour, if highly acidic cocoa beans are used. The pH of cocoa powder will not be very much above 8.0, even after using the maximum quantity of potash. 42.6.1.2 Pressing The cocoa mass is pumped to horizontal hydraulic presses, with pots lined up face to face, each equipped with very fine mesh filter screens. When all the pots are filled with mass at a temperature of 90 oC, the hydraulic ram is set in motion and the cocoa butter begins to flow through the screens on both sides of pot (each). The pressure is then increased to 400 bars. The hard cocoa cakes remaining are then discharged from the press. Cocoa butter collected also has small amount of tiny nonfat particles and so filtered through filter paper. 42.6.1.3 Blending of cocoa cake, grinding and cooling Blending of pieces of broken cake before grinding allows standardization of colour, or preparation of blends with intermediate colours. The press cakes are broken and then ground to powder in pin or other mills. The cocoa powder leaves the mill hot. Hence, it should be completely cooled before packing otherwise the setting fat will turn it into hard lumps inside the package. 241 FOOD TECHNOLOGY – I 42.6.2 Types of cocoa powder Pressing can be performed to a fat content in the cake of 20% (giving cocoa powder) or to 10% (giving low-fat cocoa powder), while alkalizing process creates many different colours. Cocoa powder with 20% fat is the common household type. The food industry uses mostly low-fat cocoa powder (10%) in many differentcolours. 42.6.3 Packaging, transport and shelf life Paper or tin is used for retail packaging; for bulk 25 kg multiple paper bags are used. When packed in air and moisture-proof containers, the flavour remains good even after 10 years. Only some fading of colour may be noticed, comparable with fat bloom on chocolate. This disappears when the cocoa is used in milk. 42.7 Cocoa Butter Pure press butter needs no cleaning at all (besides filtration), but is frequently deodourized for use in milk chocolate in order to obtain the desired milk flavour. 42.7.1 Deodourization and blending Crude cocoa butter has a strong flavour. This is desirable in dark chocolate. In milk chocolate much more cocoa butter is used and cocoa flavour would become too strong, suppressing the milk flavour. To get cocoa butter with a weakflavour, or no flavour at all we can resort to steam deodorization of cocoa butter and blending crude and deodourized butter to desired flavour. 42.7.2 Composition of cocoa butter Palmitic, Stearic and oleic acid generally account for ~95% of the fatty acids in cocoa butter. Of the remaining acids, linoleic acid is present at the highest level. Cocoa butter comprises of 52-57% of the cotyledon dry weight. The triglycerides consist of 37% oleic, 32% Stearic, 27% palmitic and 2.5% linoleic acids (as % of total fatty acids). POS, SOS and POP by far are the predominant triglycerides. 42.7.3 Properties of cocoa butter Cocoa butter is one of the most expensive natural fats, due to its unique melting behaviour. Some important properties of cocoa butter is provided in Table 42.3. The quality of cocoa butter is based on: v Hardness of fat at room temperature, and v Melting and solidification behaviour. 242 WWW.AGRIMOON.COM Table 42.3 Properties of Cocoa butter Parameters Pure pressed cocoa butter Expeller/Refined cocoa butter FFA, % Max. 1.75 1.75 Unsaponifiable, % Max. 0.53 0.50 Moisture and volatiles, % Max. 0.20 0.20 33-42 33-42 Iodine value Cocoa butter has a much narrower melting range than any other fat. Cocoa butter starts melting at 31.7 oC and is completely fluid at 33.3oC. This quality is fundamental to chocolate. Chocolate should be hard, even in hot weather and it should not stick to the fingers. On eating, the cocoa butter in the chocolate should melt completely in the mouth or else get waxy sensation in the mouth. At room temperature, a substantial part of the triglycerides in cocoa butter are solid (~60%), whereas all become liquid in the mouth. The melting takes up a considerable amount of heat, causing a cooling in the mouth which greatly contributes to the pleasant taste sensation, when eating chocolate. When chocolate is cooled and the fat solidifies, a considerable decrease in volume takes place. This contraction makes it easy to release chocolate articles from their moulds. 42.7.4 FSSAI requirement for Cocoa Butter Cocoa butter means the fat obtained by expression from the nibs of the beans of Theobroma cocoa L. It shall be free from other oils and fats, mineral oil and addedcolours. It shall conform to the following standards (Table 42.4): Table 42.4 FSSAI requirements for Cocoa butter. Free fatty acids (calculated as % oleic acid) Not more than 1.5 Iodine value 32 to 42 Melting point 29 to 34oC Butyro refractometer reading at 40oC 40.9 to 48.0 OR Refractive Index at 40oC 1.4530-1.4580 Saponification value 188 to 200 243 FOOD TECHNOLOGY – I 42.7.5 Packaging, transport and shelf-life of cocoa butter Cocoa butter is packed in 30 kg slabs or transported and stored in a liquid form. The shelf life of cocoa butter is good, due to its high degree of saturation and the shelf life of solid cocoa butter is several months to a year, if properly packed and stored. 42.8 Cocoa Butter Extenders/Replacers Since Cocoa butter is highly expensive, the food industry tries to utilize some cocoa butter alternatives that may reduce the cost of the resultant product, at the same time have properties similar to the one provided by cocoa butter. 42.8.1 Cocoa butter equivalents (CBE) They have characteristics and properties similar to those of cocoa butter and can be mixed with cocoa butter in any proportion. 42.8.2 Cocoa butter extenders (CBX) They do not necessarily have the physic-chemical characteristics similar to those of cocoa butter and they are used as extenders, where partial replacement of cocoa butter is to be used. 42.8.3 Cocoa butter substitute (CBS) fats They have their own physic-chemical properties which may not be similar to those of cocoa butter. CBS serve as the cheaper source of fats which perform as cocoa butter and which can be processed like cocoa butter. These fats include Sal, Mowrah, Kokum, Mango, etc. Cocoa butter replacer fats, which replace cocoa butter partially or fully in different chocolate or chocolate products, can be classified into three groups: (1) Laurics (hydrogenated palm kernel oil or hydrogenated coconut oil) (2) Hydrogenated fat fractions (3) Fats with symmetrical disaturated, monounsaturated glycerides, so called cocoa butter equivalents (CBEs). The first two types are not compatible with cocoa butter and are used in cheaper products. The use of these fats produces blooming and softening of the product. Blooming results from incomplete fat crystallization. The examples of some cocoa butter alternatives are furnished in Table 42.4. 244 WWW.AGRIMOON.COM Table 42.5 Cocoa butter alternatives – typical examples, properties and composition Alternatives Plant fat types Functions Main Triglycerides Cocoa Butter Equivalents Palm oil, Illipe butter, Shea butter, Kokum butter, Sal fat Non-lauric frat, Does not alter the properties of cocoa butter in mixture POP, POS, SOS Cocoa butter Replacers Soya oil, Rape seed oil, Cotton Partially compatible with different trigylcerides PEE, SEE Cocoa Butter Substitutes Coconut oil, Palm kernel oil, MCT Lauric fat, suitable for 100% substitution only LLL, LLM, LMM P – Palmitic, S – Stearic, O – Oleic, E – Elaidic, L – Lauric, M – Myristic, MCT – Medium chain triglycerides The fats called CBEs are totally compatible with cocoa butter and can be mixed with it in any proportion without affecting the physical characteristics of cocoa butter. Palm oil contains high amount of POP glyceride; some natural butter such as Shea contain SOS in large quantities and Illipe is rich in both SOS and POS. Thus, a judicious mixture of solvent fractioned palm oil, solvent fractionated shea and illipe make a blend with matches with cocoa butter. Sal or Sal fractions are the main CBE of Indian origin. ******☺****** 245
