Title of Invention	METHOD OF PREPARING CHOCOLATE AND CHOCOLATE PRODUCED BY SAID METHOD
Abstract	The invention relates to a method of producing chocolate. The method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride to a chocolate mass, the carboxylic acid not being tartaric acid. The invention also provides a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride, the carboxylic acid not being tartaric acid. In particular, the carboxylic acid ester of a diglyceride in the present invention is a citric acid ester of a diglyceride, preferably added to the chocolate mass before or during conching.

Title of Invention

METHOD OF PREPARING CHOCOLATE AND CHOCOLATE PRODUCED BY SAID METHOD

Abstract

The invention relates to a method of producing chocolate. The method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride to a chocolate mass, the carboxylic acid not being tartaric acid. The invention also provides a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride, the carboxylic acid not being tartaric acid. In particular, the carboxylic acid ester of a diglyceride in the present invention is a citric acid ester of a diglyceride, preferably added to the chocolate mass before or during conching.

Full Text	METHOD OF PRODUCING CHOCOLATE ADDING A CARBOXYLIC ACID ESTER OF A DIGLYCERIDE TO A CHOCOLATE MASS, AND A CHOCOLATE COMPOSITION PRODUCED BY SAID METHOD. FIELD OF THE INVENTION The present Invention relates to a method of producing chocolate. The method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride to a chocolate mass, the carboxylic acid not being tartaric acid. The invention also provides a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride, the carboxylic acid not being tartaric acid. In particular, the carboxylic acid ester of a diglyceride in the present invention is a citric acid ester of a diglyceride, preferably added to the chocolate mass before or during conching. BACKGROUND OF THE INVENTION Interface active substances, known as emulsifiers, are used in the food industry to ensure the right suspension of one phase in another, as in the mixture of oil and water. The amphlphillc character of Interface active substances allows more or less hydrophobic substances to be suspended with more or less hydrophilic substances. Thereby, interface active substances contribute to more appetising food qualities by improving appearance and consistency. Emulsifiers are also used in the chocolate industry as additives In the production of chocolate to improve the appearance and consistency of chocolate products. The appearance and consistency are in the same way improved when using emulsifiers In chocolate imitations, so called compounds. An important aspect in the production of chocolate Is flow properties of the melted chocolate mass. To get an optimal product it is of great importance to be able to regulate the flow properties of the chocolate mass. The flow properties are also important for later applications of the chocolate mass, such as in use as couverture, enrobing fillings, nuts, moulding, etc, The flow properties of a chocolate mass are characterised by the plastic viscosity and the yield value. The yield value is related to the force to start the flow of the chocolate, and the plastic viscosity is related to the work that Is required to keep the chocolate flowing. Chocolate Is pseudo plastic In that the apparent viscosity decreases when the shearing stress is Increased. Chocolate has a positive yield value, which means that an initial amount of energy is required to start flow of the chocolate. Substances such as soy lecithin, ammonium phosphatlde and PGPR (polyglycerol polyricinoleate) are generally used within the chocolate and candy industry to adjust the flow properties of chocolate. Soy lecithin and other vegetable lecithin's are glycerol phospholipids, a group of substances coming out as by-products from the refining of vegetable oils. In general, the biggest fractions of glycerol phospholipids are characterised by its chemical structure as being glycerol esterified in the 1-posltlon and In the 2-position with fatty acids, while the 3-position is esterified with a group of phosphate. Lecithin is effective in improving the flow properties of chocolate and is widely used for commercial benefit as a partial cocoa butter replacer. It has been reported that the addition of 0.1-0.3% soy lecithin reduces the viscosity by more than 10 times its own weight of cocoa butter. In the chocolate industry there Is a long felt need for a substitute to soy lecithin. Soy lecithin is characterised by an Intense taste and. smell of soy. Especially during storage, soy lecithin gives the chocolate a bad taste. Also, lecithin is frequently based on GMO soy, which at the moment is not allowed in all countries. The effect by adding lecithin Is a reduction of the viscosity with increasing addition up to 0,7% wt. after which addition of lecithin gives a negative effect on viscosity. Lecithin does generally not Influence and thus reduce the yield value, which may be a drawback using lecithin. Thus, alternative emulsifying agents have been introduced to overcome the problems involved by using lecithin. One such alternative emulslfler is described in the European patent application, EP 1069831 Al, in which a low fat chocolate and a low fat chocolate product Is prepared. The main focus Is to Improve the emulsification of the chocolate to achieve better plastic viscosity and yield value. Among the emulsiflers used to obtain the effect is lecithin and dlacetyl tartaric esters of mono- and dlglycerides. Another European patent, EP 0667746 Bl, describes a chocolate composition with a low fat content and a process to prepare the composition. The composition comprises at the most 1% of an emulsifier to Improve the flow properties of the chocolate. Applicable emulsiflers are mono-'and diglycerides, lecithin and also diacetyl tartaric esters of mono- and diglycerides. The Danish patent application, DK A 9700390, describes the application of a citric acid ester of a monoglyceride as viscosity regulating emulsifler in chocolate. In the examples It Is described that the citric acid ester Is added to a compound, a vecao, and the plastic viscosity and the yield value are determined versus a soy lecithin reference. Surprisingly, using a citric acid ester of a diglyceride in the present invention has turned out to be considerably more effective than conventional emulslfiers described In the art. Furthermore, by using mixtures of citric acid esters of diglycerides and monoglycerides, an additionally Improvement has been achieved with still better results. SUMMARY OF THE INVENTION Accordingly, In a first aspect the present invention provides a method of producing chocolate, the method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxyllc acid ester of a diglyceride, to a chocolate mass, the carboxyllc acid not being tartaric acid. In a further aspect, the present Invention provides a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride, the carboxyllc acid not being tartaric acid. In particular, the carboxyllc acid ester of a diglyceride In the present Invention Is a citric acid ester of a diglyceride, preferably added to the chocolate mass before or during conchlng. DETAILED DESCRIPTION OF THE INVENTION One object according to the present Invention Is to obtain a reduction and/or a control of the flow properties including the plastic viscosity and the yield value, which will Imply a number of advantages. When using a carboxylic acid ester of a diglyceride, such as a citric acid ester of a diglyceride, It Is possible to reduce the total fat content in the chocolate and still keep flow properties known from chocolate containing high fat content. This ensures economic advantages by reducing the costs of cocoa butter, but also by reducing the fat energy percentage In the chocolate. In addition to the above mentioned advantages, another object is to obtain process advantages owing to the fact that a reduction/adjustment of the viscosity and the yield value of the melted chocolate will make It far more easy to mould the chocolate in bars or figures. Also, the use of chocolate as couverture, enrobing fillings, nuts, etc may be easier. Chocolate moulded, generally may be somewhat more viscous than coating chocolates since the chocolate may be vibrated into a mould over a longer period of time than allowed In enrobing. Furthermore, the use of a carboxyllc acid ester of a diglyceride, such as a citric acid ester of a diglyceride, ensures homogeneity between the Individual productions securing a uniform quality of the chocolate products. Another advantage of the present invention may be the emulsifier's effect on the temper of the chocolate compared to other emulslflers used in chocolate , i.e. the crystallization of the cocoa butter. The emulsifler of the present invention ensures easy formation of, and a high fraction of, the correct crystallization form of the cocoa fat, as this may be important for the texture and for the organoleptic qualities of high quality chocolates. Also, considerations must be made to the fact that the crystallized article will shrink in the moulds, which means that there is a need for easy release from the moulds. Thus, the present invention relates to a method of producing chocolate, the method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxyllc acid ester of a diglyceride to a chocolate mass, the carboxylic acid not being tartaric acid. In the present context, It should be understood that "chocolate" relates to what Is traditionally regarded as "real chocolate" and so called "compounds", which are chocolate Imitations. Thus, the term "chocolate" in the present context may comprise cocoa mass, cocoa fat and sugar. Cocoa fat accordingly should be Interpreted as being selected from the group consisting of cocoa butter, cocoa butter substitute, cocoa butter equivalent, cocoa butter replacer, and any mixture thereof such as used In the application of vecao. Additionally, the chocolate mass may comprise a milk additive. The chocolate mass may additionally comprise any other additive to alter the physical or chemical properties of the chocolate, such as non-fat cocoa solids, sugar substitutes, natural and artificial flavors (e.g., vanillin, spices, coffee, ethyl vanillin, salt, brown nut-meats, natural vanilla, etc., as well as mixtures of these), antloxldants (e.g., preservatives such asTBHQ, tocopherols and the like), proteins, and the like. It follows that "chocolate mass" Is a mixture of the Ingredients in "chocolate", and the two terms should be Interpreted in the same way in the context of the present invention. The process of making chocolate is reviewed In B. L. Zoumas and E. J. Flnnegan, "Chocolate and Cocoa", Klrk-Othmer Encyclopedia of Chemical Technology, Vol. 6 (3rd Ed., Wiley-Interscience, New York) 1-19 (1985). Some of the considerations present in the production of chocolate are described below, though a person skilled in the art Is aware of considerations not explicit mentioned in the text. During the production of chocolate, the chocolate mass undergoes a mechanic conching process. The mechanical conching process takes place after the Ingredients have been well mixed and the chocolate mass subsequently has been rolled. During conching, the chocolate mass obtains Its physical properties and characteristic aroma. The crumbled chocolate mass Is subjected to an intensive mixing ensuring that all dry particles are coated by fat, thus converting the chocolate mass to a liquid suspension with solid coated sugar particles, which gives the chocolate a good smooth texture when eaten. A mixing-kneading process allows moisture and volatile components to escape while smoothing the chocolate paste and is critical to the flavour and texture development of the chocolate. Alternatively to the conching step, a liquefying step mixes refined flakes under high shear over a short period of time. The refined flakes are quickly converted to a suspension of solids in a continuous fat phase. The lack of flavour development can be corrected by pretreating the liquor and cocoa butter. Additional fat and emulslfiers are then traditionally added in the standardizing or finishing step to adjust viscosity to final specifications. The final step in obtaining the desired rheology of the chocolate Is tempering, a process of Inducing satisfactory crystal nucleatlon of the liquid fat in the chocolate. If the chocolate Is Improperly cooled, the resulting chocolate will have a grainy texture as well as poor color and appearance. Finished chocolate is a suspension of very fine particles (usually less than 50 microns) in fat. The particles usually consist of cocoa solids and crystalline sucrose as well as milk solids in the case of milk chocolate. The cocoa solids In the chocolate liquor and the milk solids have normally been processed so that they are fine enough to be Incorporated Into a chocolate mixture. Sucrose, however, requires considerable size reduction since extra fine grade sucrose, for example, typically varies in crystal size from about 40 to 1000 microns. To fulfil the function as an ingredient in chocolate, therefore, these sucrose crystals should be reduced In size to less than about 50 microns.. It is known that at least about 50% of the surface area of particles in milk chocolate are produced by the presence of particles below two microns In size. The presence of these ultra fine particles Increases viscosity and Increasing amounts of fat, e.g., cocoa butter, are required to coat such particles In order for the chocolate to flow properly In manufacturing operations. It is well known in the art that the amount of fat present in chocolate will affect the flow properties of the chocolate, I.e., the addition of fat to a chocolate decreases both the yield value and the plastic viscosity. Consequently, fat content may therefore be varied according to the intended use. Chocolates contain a very large amount of small sugar particles. Fat does not cover the surface of the sugar particles very easily and consequently, anything which will form an interface between the sugar and fat will aid in the flow of the chocolate. Emulsifiers, may produce such an Interface by coating the surface of the solid particles, In particular, the sugar. Thus, an emulsifying agent may be added to the chocolate mass. In the present invention carbohydrate sweeteners, In the following termed sugars, with varying degrees of sweetness intensity are useful as additives In the preparation of chocolate and may be any of those typically used In the art. These sugars include, but are not limited to, sucrose, (e.g., from cane or beet), dextrose, fructose, lactose, maltose, glucose syrup solids, corn syrup solids, invert sugar, hydrolysed lactose, honey, maple sugar, brown sugar, molasses and the like. The nutritive carbohydrate sweetener, preferably sucrose, will be present in the chocolate as crystals or particles. Particle size of Ingredients Is also known to influence the viscosity of chocolate. As a general rule, viscosity will Increase with decreasing particle size. An excess of fine particles below 5 microns whether derived from the sugar, milk, or chocolate liquor/powder component, will make the chocolate extremely thick and difficult to manage during pumping, depositing, and enrobing operations. Coarse particles which exceed 60 microns will tend, however, to give the chocolate a gritty sandy texture which Is unacceptable to consumers. Preferably, the particle size is around 20 microns, but In some applications it is suitable with particles in the range between 20 to 60 microns. To ensure the right flow properties of the chocolate in the present invention, a chocolate emulsifying agent Is added to the chocolate mass. The term "chocolate emulsifying agent" should be Interpreted as an emulsifying agent applicable In chocolate, which is able to alter the flow properties of the chocolate mass and which Is edible. An emulsifying agent In the following Is abbreviated an emulslfier. The emulslfier Is preferably gdded during conchlng of the chocolate mass according to the present Invention. Depending on the composition of the chocolate, the emulslfier may be added In the beginning of the conching. The emulslfier alternatively may be added in one or more doses while conchlng or It may be added in the end of the conching, for example If the viscosity of the chocolate mass should not be lowered too much. Alternatively, the emulsifier may'be added to the chocolate mass before conching. This addition may have some advantages, for instance practical advantages. Preferably, the emulsifier of the present Invention Is a carboxylic acid ester of a diglyceride, the carboxylic acid not being tartaric acid, more preferably the emulsifier is a hydroxy carboxylic acid ester of a diglyceride, more preferably the carboxylic acid is a hydroxy tricarboxylic acid ester of a diglyceride and most preferably the emulsffier is a citric acid ester of a diglyceride. Tartaric acid is not comprised in the group of carboxylic acid ester of a diglyceride and for brevity, the following text does not disclaim tartaric acid, though it should be understood as such. To ensure the right emulsion, the emulsifier preferably comprises at least 10% wt. of a carboxylic acid ester of a diglyceride In the present invention. Alternatively, the emulsifier comprises at least 20% wt. of a carboxylic acid ester of a diglyceride, such as at least 30% wt., 40% wt., 50% wt., 60% wt., 70% wt., 80% wt., 90% wt., or at least 95% wt. In particular, the emulsifier comprises at least 11% wt., 12% wt., 13% wt., 14% wt., 15% wt., 16% wt., 17% wt., 18% wt., 19% wt. of a carboxylic acid ester of a diglyceride, or at least 21% wt., 22% wt., 23% wt., 24% wt., 25% wt., 26% wt., 27% wt., 28% wt., 29% wt. of a carboxylic acid ester of a diglyceride, or at least 31% wt., 32% wt., 33% wt., 34% wt., 35% wt., 36% wt., 37% wt., 38% wt., 39% wt. of a carboxylic acid ester of a diglyceride, or at least 41% wt., 42% wt., 43% wt., 44% wt., 45% wt., 46% wt., 47% wt., 48% wt., 49% wt. of a carboxylic acid ester of a diglyceride, or at least 51% wt., 52% wt., 53% wt., 54% wt., 55% wt., 56% wt., 57% wt., 58% wt., 59% wt. of a carboxylic acid ester of a diglyceride, or at least 61% wt., 62% wt., 63% wt., 64% wt., 65% wt., 66% wt., 67% wt., 68% wt., 69% wt. of a carboxylic acid ester of a diglyceride, or at least 71% wt., 72% wt., 73% wt., 74% wt., 75% wt., 76% wt., 77% wt., 78% wt., 79% wt. of a carboxylic acid ester of a diglyceride, or at least 81% wt., 82% wt., 83% wt., 84% wt., 85% wt., 86% wt., 87% wt., 88% wt., 89% wt. of a carboxylic acid ester of a diglyceride, or at least 91% wt., 92% wt., 93% wt., 94% wt., 95% wt., 96% wt., 97% wt., 98% wt., 99% wt. of a carboxylic acid ester of a diglyceride. In addition to the carboxylic acid ester of a diglyceride, the emulsifier may comprise a further emulsifying agent. This further emulsifying agent Is selected from the group consisting of a carboxylic acid ester of a monoglyceride, a carboxylic acid ester of a diglyceride, a phospholipid, a phosphollpld derivative, a polyglycerol ester of polyriclnolic acid, an ammonium phosphatide and any combination thereof. Phospholiplds may preferably be lecithin. In another embodiment this further emulsifying agent may be lecithins enriched in either phosphatldyl choline or phosphatldyl ethanolamlne or both, mono- and dlglycerides, diacetyl tartarlc acid esters of mono- and diglycerides, monosodium phosphate derivatives of mono- and diglycerides of edible fats or oils, sorbitan monostearate, polyoxyethylene sorbltan monostearate, hydroxylated lecithin, lactylated fatty acid esters of glycerol and propylene glycol, polyglycerol esters of fatty acids, propylene glycol mono- and dlester of fats. In addition, other emulsifiers that can be used in the present invention, include ammonium salts of phosphatidic acid, sucrose esters, oat extract, etc., any emulsifier found to be suitable in chocolate or similar fat/solid system or any blend provided the total amount of emulsifier does not exceed 1% by weight. Thus, any combination between the carboxylic acid ester of a diglyceride and a further emulsifying agent Is comprised in the present invention. This combination may be between the carboxylic acid ester of a diglyceride and one, two, or more of the further emulsifying agents. For example the combination may be a carboxylic acid ester of a diglyceride and a further carboxylic acid ester of a monoglycerlde. The selection of a suitable further emulsifying agent may depend on the required flow properties In the final chocolate product. Accordingly, the further emulsifying agent may be added to the chocolate mass up to the missing amount of emulsifier. If e.g. the carboxylic acid ester of a diglyceride Is added in an amount of 10% wt., then the further emulsifying agent may be added in an amount of up to 90% wt. If a further emulsifying agent is added to the chocolate mass, the further emulsifying agent may comprise up to 90% wt. of the chocolate mass In any Individual specified amount. On the other hand if the carboxylic acid ester of a diglyceride is added in an amount of 20% wt., the further emulsifying agent may comprise up to 80% wt. of the added emulsifiers, etc. Preferably, the further emulsifying agent in the present Invention is a carboxylic acid ester of a monoglyceride. The carboxylic acid ester of a monoglycerlde may preferably be a hydroxy carboxylic acid ester of a monoglycerlde, and most preferably be a citric acid ester of a monoglyceride. In a presently preferred embodiment, the chocolate emulsifying agent essentially consists of a carboxylic acid ester of a monoglyceride and a carboxylic acid ester of a diglyceride. A presently more preferred embodiment of the Invention Is to add a citric acid ester of a diglyceride and as a further emulsifying agent add a citric acid ester of a monoglyceride. Accordingly, In a useful embodiment the chocolate emulsifying agent essentially consists of a citric acid ester of a monoglyceride and a citric acid ester of a diglyceride. When using the term "essentially", it Is understood In the art that the purity of the fractions may never be 100%. There may be contaminants or other residues in the fractions, such as triglycerldes, free glycerols, etc. In one presently preferred embodiment, when the chocolate essentially consists of a carboxylic acid ester of a diglyceride and a further emulsifying agent, such as carboxylic acid ester of a monoglyceride, the carboxylic acid ester of a diglyceride preferably is In the range of 30 to 90% wt., more preferably 40 to 90% wt., still more preferably 50 to 90% wt., still more preferably 50 to 80% wt., still more preferably 50 to 70% wt, most preferable 50 to 60% wt. such as around 50% wt. Thus, the ratio between carboxylic acid ester of a diglyceride and a further emulsifying agent, such as carboxylic acid ester of a monoglyceride, comprising the emulsifier is from 3:7 to 9:1, more preferably from 4:6 to 9:1, still more preferably from 1:1 to 9:1, still more preferably from 1:1 to 8:2, still more preferably from 1:1 to 7:3, most preferable from 1:1 to 6:4, such as around 1:1. Disregarded In the ratios are contaminants, other residues in the fractions, or free fatty acids such as triglycerldes, free glycerols, etc. The emulsifier applied in the present invention may be derived from a natural occurring fatty acid or derivatives thereof. The naturally occurring fatty acids may be selected from the group consisting of rapeseed oil, castor oil, maize oil, cottonseed oil, olive oil, palm oil, safflower oil, sesame oil, soybean oil, sunflower oil, and any mixture thereof and any derivative thereof. Preferably, the fatty acid is rapeseed oil or a derivative thereof. It should though be understood that the fatty acids might be derived from other sources in the present invention. In the presently most "preferred embodiment, the emulsifier Is derived from rapeseed oil or a derivative thereof. The carboxylic acid ester applied In the present invention preferably Is derived from naturally occurring fatty acids with iodine values of at least 45. Alternatively, the iodine value of the fatty acids Is at least 55, preferably around 55. Characteristic to the fatty acids Is that the esterlflcatlng fatty acids preferably are saturated or unsaturated fatty acids with 14 to 18 carbon atoms, more preferably with 16-18 carbon atoms. As an option the esterificating fatty acids are saturated or unsaturated fatty acids with up to 22 carbon atoms, such as up to 20 carbon atoms. The carboxylic acid ester of a diglyceride preferably has a saponlficatlon value of between 260 to 330, more preferably between 300-330. The carboxyllc acid ester of a diglyceride furthermore preferably has an acid value of between 10-80, more preferably between 50-70. In order to produce a chocolate with acceptable flow properties, it is also essential to keep the moisture content low. It is well known within the chocolate industry that moisture content has a significant effect on the flow properties of chocolate. If water is added to chocolate, a marked increase in viscosity occurs. It has been previously reported that both the yield value and plastic viscosity Increase with moisture levels above 1.1%. Between 0.6-1.1% moisture, the plastic viscosity is nearly constant whereas the yield value rises with Increasing moisture. This could be explained by the formation of layers of syrup on the surface of sugar , particles with an Increase in moisture, which increases the friction between the said particles. The most preferred carboxylic acid ester in the present invention, citric acid ester of a diglyceride, may be prepared by a reaction between citric acid and diglyceride. The ratio between the reactants, the reaction temperature and the reaction time Is determining the degree of esterfication. Diglyceride traditionally is prepared by trans esterflcation of triglycerldes with glycerol, by the invention is though not limited to this reaction. Heating the mixture of the prepared diglyceride and citric acid performs the esterlficatlon to give the citric acid ester of diglyceride. Diglyceride may be preheated before the addition of citric acid, and then the heating preferably Is continued until reaction temperature Is obtained. The temperature of the preheated diglyceride may generally be 80°C to 120°C and preferably 90°C to 110°C and more preferably 100°C. The reaction temperature may generally 100°C to 160°C and preferably 120CC 150°C and more preferably about 140°C. The reaction mixture Is typically maintained at a pressure of 10 to about 760 mmHg and more preferably maintained at a pressure form about 20 to 200 mmHg and most preferably about 50 mmHg. Prior to and/or during the reaction, the reaction mixture may advantageously be covered with an Inert gas such as nitrogen. The water being released during the reaction may continuously be removed from the reaction mixture by evaporating and condensing the water vapour. The weight ratio of citric acid to diglyceride In the reaction mixture broadly may range from 1:10 to about 1:2. Preferably the weight ratio Is from 1:10 to about 1:4 and more preferably about 1:5. Generally, the esterificatlon reaction may be performed for about 1-20 hours and preferably 5-10 hours and more preferably 8-10 hours. Conchlng for extended periods of time (longer than 4 hrs.) at elevated temperatures (above 100 DEG F.) is well known to be an effective method for removing water and offlavours from chocolate paste. The initial ingredients should be selected to have low moisture, and chocolate processing should be done so that moisture uptake from the atmosphere by hygroscopic ingredients Is kept to a minimum. The addition of chocolate emulsifying agents in the present Invention is in the amount of between 0,2 to 1,0% wt. of the chocolate mass, more preferably between 0,4 to 0,8% wt., most preferably between 0,5 to 0,6% wt. The amount of added emulsifier depends for Instance of the flow requirement of the chocolate mass. The chocolates of the present Invention may contain a trace of water. It Is preferred that they contain less than 1% moisture, preferably less than 0.75% by weight, in order to meet the flow requirements. Higher moisture is very detrimental to the yield value and plastic viscosity. Finally, the second aspect of the present Invention is a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxyllc acid ester of a diglycerlde. The composition Is provided by the present method according to the invention and thus all features and embodiments as described In the text above can be combined in all relevant ways with the second aspect of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig.l is a comparison of functionality as Yield Value and Plastic Viscosity for citric acid esters with different monoglycerlde percentage. The prepared citric acid esters are also compared with two commercial citric acid esters from the marked. Fig.2 is a comparison of functionality as Yield Value and Plastic Viscosity for mixtures of citric acid ester of monoglyceride and citric acid ester of diglyceride. Fig.3 Is a comparison of functionality as Yield Value for different dosage of different citric acid esters. Fig.4 Is a comparison of functionality as Plastic Viscosity for different dosage of different citric acid esters. Fig. 5 is a comparison of functionality as Yield Value and Plastic Viscosity for different citric acid esters In Compound. Fig. 6 Is a comparison of functionality as Yield Value and Plastic Viscosity for different citric acid esters made In pilot scale. EXAMPLES A general procedure for determining the yield value and plastic viscosity in chocolate. The functionality of the citric acid esters in chocolate was determined by measure of yield value and plastic viscosity. The measure was made on a Haake Viscometer RV1 by a rotor-cup system. The rotor was a Z38 DIN53018. After the measure, the yield value and plastic viscosity were determined by the use of the rheology casson-model. Example 1: Citric acid esters with variation of the ratio of monoglyceride and diglyceride. Glycerides In varying ratio of monoglyceride and diglyceride were charged to a reaction flask. The reaction flask was equipped with a mechanical stlrrer, nitrogen Inlet, vacuum capabilities to 1 mmHg, steam outlet, thermometer and temperature controlled heating mantel. The glycerides were heated until 100°C with good agitation. Citric acid, 20% In weight, was added to the glycerlde, and then the heating was continued until 140CC. After the addition of citric acid, the pressure in the reaction flask was gradually reduced to 50 mmHg. The reaction was continued for 5 hours. Then the reaction mixture was cooled to below 80°C before discharge. After the completion of the reaction, the resulting citric acid esters were analysed for functionality In a milk chocolate. The result of the analyses of functionality are summarised In the below table 1 and fig. 1. MG Is the fraction of monoglyceride, and positive signs in last two columns mean a better result compared to the reference compound Lecithin. In figure 1, a number of measurements of the plastic viscosity are stated In a 32% chocolate In which the ratio of monoglyceride and diglyceride Is from 98/2 to 5/95. From the measurements it appears that the 98/2 diglyceride citric acid ester gives a much better, I.e. lower, plastic viscosity compared to the citric acid ester of monoglyceride, where the mono percentage at the distillation is exceeding 90%. It Is particularly interesting to observe the functionality (the efficiency) of different citric acid esters of mono- and diglycerides, when changing the proportion between the two glycerides that the efficiency of the emulsifiers increases with an optimum at approximately a 1:1 mixture of the two glycerides. When exceeding the 50% monoglyceride moiety content, the functionality of the esters rapidly decreases with increasing content of monoglyceride. For diglycerides of a commercial purity of minimum 98% diglyceride and a maximum of 2% monoglyceride as an unavoidable contaminant, the corresponding citric acid ester derivative thus has shown to be surprisingly efficient reducing both viscosity and yield value in a chocolate mass. The reduction is In the order of between 0.5 to 1 time compared to traditionally applied emulsifiers, such as soy lecithin. By way of comparison, some single values from tests with citric acid esters of monoglycerides are shown in the form of two commercial products: Citrem 211 and Citrem 5010. The same picture is observed at analogue tests of the citric acid esters, as stated above, but by choosing other types of chocolate, for example pure bitter, and rich in fat, and compounds. Obviously citric acid esters based on diglycerides or up to 50/50 mixtures with monoglycerides give a good reduction of both the plastic viscosity and of the yield value of chocolates and compounds. At a higher ratio of the including monoglyceride the efficiency decreases. Table 1: (Table Removed) Example 2: Mixtures of a citric acid ester of a monoglyceride and a citric acid ester of a diglyceride, with variation of the ratio. A citric acid ester of a monoglyceride (96%) and a citric acid ester of a diglyceride (97%) were made according to Example 1. From the two citric acid esters, mixtures with a varying ratio of monoglyceride and diglyceride were separately mixed In a reaction flask. The reaction flask was equipped with a mechanical stlrrer, a nitrogen Inlet, a thermometer and temperature controlled heating mantel. The mixtures were heated until 80°C, when good agitation. After 5 mln. of agitation at 80°C, the mixtures were discharged. After the completion of the mixing, the resulting citric acJd esters mixtures were analysed for functionality In a milk chocolate. The result of the analyses of functionality are summarised In the below table 2 and fig. 2. MG is the fraction of monoglyceride, and positive signs In last two columns mean a better result compared to the reference compound Lecithin. Table 2: (Table Removed) Example 3: Functionality of citric acid esters, with different dosage, in chocolate. A citric acid ester of a monoglyceride (96%), a citric acid ester of a dlglyceride (97%) and a citric acid ester of 50% monoglyceride and 50% diglycerlde, were made according to Example 1. A typical commercial lecithin was used as the reference compound. Functionality of different dosage of the citric add esters was determined In a milk chocolate, then compared with the reference compound. The result of the analyses of functionality Is summarised In the below table 3 and figure 3-4. MG is the fraction of monoglyceride, DG Is the fraction of diglycerlde, and positive signs in last two columns mean a better result compared to the reference compound Lecithin. In the present example It has been demonstrated that the esterlfication with the citric acid can be done on the pure components, I.e. diglycerlde and monoglyceride. Esterlfication can also be done as prebelended mixtures of the two types of glycerides. No difference in the functionality of two corresponding formulations Is observed. Thus, the dlglycerides can e.g. be produced as a residue fraction (heavily boiling) from the distillation of the monoglycerides (light boiling). The monoglyceride citric acid ester can then be mixed in the required ratio to obtain the optimal point as to the functionality. In a more rational way the esterificatlon can also be done on the mono- and diglycerlde, i.e. the equilibrium mixture being normally available as a raw material from which the monoglyceride is distilled. This considerably simplifies the process. Costly and complicated distillation of the monoglyceride Is avoided, Implying that one process step Is eliminated before the esterificatlon with the citric acid, a fact which renders the process more attractive on a economical point of view than it will be by using the solution with the distilled monoglyceride. Table 3: (Table Removed) Example 4: Temper ability of milk chocolate, Lecithin versus citrlc-acld-ester Chocolate test system A standard milk chocolate system Is chosen as the chocolate model system to demonstrate in any of the tested emulslfiers Is affecting the tempering application of chocolate. The total fat content is around 32% wt. fat, and the amount of whole milk powder is 23% wt. Particle size of the milk chocolate Is max 25 micron. Since milk chocolate Is the most difficult type of chocolate to temper, this is the system that is chosen. It is tested If It is possible to temper all milk chocolates (added different emulslfiers) to a practical and producible state and furthermore If some of the emulslfiers course changes in the temperature settings needed to obtain a well tempered chocolate. Equipment Palsgaard is using a Aasted AK-10 pilot plant tempering machine to conduct the tempering process. For evaluation of the degree of temper a Exotherm 7400 is used. The cooling cell of the temper-meter Is set at 8,0°C. Temper table comments In order to understand the Information given in table 4, some comments must follow. The column saying "State at temperature 21.5°/20.7°/29.5°C" Is the start temperature for all the measurements. Slightly under tempered is better than under tempered (better meaning less influence at the cocoa butter crystallisation). The following Information about Inflexion at different temperatures It is desirable to get Inflexion (cocoa butter crystal formation) at as high a temperature as possible. So the perfect outcome would be If all Inflexions came at 22°C (or at higher temperatures). Conclusion All the 4 emulslfier can be tempered at both 0,60 and at 1,0% without any serious difficulties, but of the four tested emulsiflers, the citric acid ester of dlglyceride is found to be the easiest to temper. There is a general tendency in all the 4 tested emulsiflers and that is that they all are slightly easier to temper at 0,60% compared to 1,0% dosage. Also slightly colder water settings should be selected at the high emulsifler dosage In order to obtain good Inflexion curves this is another Indication of a beginning Influence of the crystallisation of the chocolate fat phase. Through measurements of the chocolate's temper the additive's effect on the crystallization conditions can be evaluated, as the object is to obtain a clear Inflextion at 22°C or higher. Measurements of a chocolate's temper by adding of diglyceride citric acid ester to a chocolate have proved that the chocolate becomes only a little undertempered, whereas a clear undertempering is observed when using lecithin, At the same time it is found that a dosage of 0,6% of diglyceride citrate gives the best tempering. Table 4: (Table Removed) Example 5: Functionality of citric acid esters In compound. A citric acid ester of monoglyceride (96%), a citric acid ester of dlglyceride (97%) and a citric acid ester of 50% monoglyceride and 50% diglyceride, were made according to Example 1. A typical commercial lecithin was used as the reference compound. Functionality with dosage at 0,6% of the citric acid esters was determined in a compound with Palm Olein as fat base. The fat percent was approx. 30. Lecithin was used as reference material. The result Is summarised in the below table 5 and figure 5. Negative sign in the last two columns mean a bad result compared to the reference material Lecithin. Table 5: (Table Removed) Example 6: Citric acid esters of monodiglyceride In pilot scale. A monodiglyceride (40kg), with the composition of 43% monoglycerlde, 42% diglyceride and 15% trtglycerlde, was charged to a reaction vessel. The reaction vessel was equipped with a mechanical stlrrer, nitrogen Inlet, vacuum capabilities to 50 mbar, steam outlet, thermometer and temperature controlled heating system. The glycerlde was heated until 100°C, under good agitation. Citric acid (10kg) was added to the glyceride, and then the heating was continued until 140°C. After the addition of citric acid, the pressure In the reaction flask was gradually reduced to 90 mbar. The reaction was continued for 12 hours. Then the reaction mixture was cooled to below 80°C before discharge. After the completion of the reaction, the resulting citric acid esters were analysed for functionality in a milk chocolate. The result of the analyses of functionality Is summarised in the below table 6 and figure 6. Negative sign, in last two columns, means a bad result compared to the reference compound Lecithin. Example 7: Citric acid esters of diglyceride in pilot scale. A diglyceride (42kg) with the composition of 4% monoglyceride 91% diglyceride and 5% triglycerlde was charged to a reaction vessel. The reaction vessel was equipped with a mechanical stirrer, nitrogen inlet, vacuum capabilities to 50 mbar, steam outlet, thermometer and temperature controlled heating system. The glycerlde was heated until 100°C, under good agitation. Citric acid (10,5kg) was added to the glycerlde, and then the heating was continued until 140°C. After the addition of citric acid, the pressure In the reaction flask was gradually reduced to 90 mbar. The reaction was continued for 9 hours. Then the reaction mixture was cooled to below 80°C before discharge. After the completion of the reaction, the resulting citric acid esters were analysed for functionality In a milk chocolate. The result of the analyses of functionality is summarised in the below table 6 and figure 6. Negative sign, In last two columns, mean a bad result compared to the reference compound Lecithin. Table 6: (Table Removed) The invention relates to a method of producing chocolate. The method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride to a chocolate mass, the carboxylic acid not being tartaric acid. The invention also provides a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride, the carboxylic acid not being tartaric acid. In particular, the carboxylic acid ester of a diglyceride in the present invention is a citric acid ester of a diglyceride, preferably added to the chocolate mass before or during conching.

Full Text

METHOD OF PRODUCING CHOCOLATE ADDING A CARBOXYLIC ACID ESTER OF A DIGLYCERIDE TO A CHOCOLATE MASS, AND A CHOCOLATE COMPOSITION PRODUCED BY SAID METHOD.
FIELD OF THE INVENTION
The present Invention relates to a method of producing chocolate. The method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride to a chocolate mass, the carboxylic acid not being tartaric acid. The invention also provides a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride, the carboxylic acid not being tartaric acid. In particular, the carboxylic acid ester of a diglyceride in the present invention is a citric acid ester of a diglyceride, preferably added to the chocolate mass before or during conching.
BACKGROUND OF THE INVENTION
Interface active substances, known as emulsifiers, are used in the food industry to ensure the right suspension of one phase in another, as in the mixture of oil and water. The amphlphillc character of Interface active substances allows more or less hydrophobic substances to be suspended with more or less hydrophilic substances. Thereby, interface active substances contribute to more appetising food qualities by improving appearance and consistency.
Emulsifiers are also used in the chocolate industry as additives In the production of chocolate to improve the appearance and consistency of chocolate products. The appearance and consistency are in the same way improved when using emulsifiers In chocolate imitations, so called compounds.
An important aspect in the production of chocolate Is flow properties of the melted chocolate mass. To get an optimal product it is of great importance to be able to regulate the flow properties of the chocolate mass. The flow properties are also important for later applications of the chocolate mass, such as in use as couverture, enrobing fillings, nuts, moulding, etc,
The flow properties of a chocolate mass are characterised by the plastic viscosity and the yield value. The yield value is related to the force to start the flow of the chocolate, and the plastic viscosity is related to the work that Is required to keep the chocolate flowing. Chocolate Is pseudo plastic In that the apparent viscosity decreases when the shearing
stress is Increased. Chocolate has a positive yield value, which means that an initial amount of energy is required to start flow of the chocolate.
Substances such as soy lecithin, ammonium phosphatlde and PGPR (polyglycerol polyricinoleate) are generally used within the chocolate and candy industry to adjust the flow properties of chocolate.
Soy lecithin and other vegetable lecithin's are glycerol phospholipids, a group of substances coming out as by-products from the refining of vegetable oils. In general, the biggest fractions of glycerol phospholipids are characterised by its chemical structure as being glycerol esterified in the 1-posltlon and In the 2-position with fatty acids, while the 3-position is esterified with a group of phosphate.
Lecithin is effective in improving the flow properties of chocolate and is widely used for commercial benefit as a partial cocoa butter replacer. It has been reported that the addition of 0.1-0.3% soy lecithin reduces the viscosity by more than 10 times its own weight of cocoa butter.
In the chocolate industry there Is a long felt need for a substitute to soy lecithin. Soy lecithin is characterised by an Intense taste and. smell of soy. Especially during storage, soy lecithin gives the chocolate a bad taste. Also, lecithin is frequently based on GMO soy, which at the moment is not allowed in all countries. The effect by adding lecithin Is a reduction of the viscosity with increasing addition up to 0,7% wt. after which addition of lecithin gives a negative effect on viscosity. Lecithin does generally not Influence and thus reduce the yield value, which may be a drawback using lecithin.
Thus, alternative emulsifying agents have been introduced to overcome the problems involved by using lecithin.
One such alternative emulslfler is described in the European patent application, EP 1069831 Al, in which a low fat chocolate and a low fat chocolate product Is prepared. The main focus Is to Improve the emulsification of the chocolate to achieve better plastic viscosity and yield value. Among the emulsiflers used to obtain the effect is lecithin and dlacetyl tartaric esters of mono- and dlglycerides.
Another European patent, EP 0667746 Bl, describes a chocolate composition with a low fat content and a process to prepare the composition. The composition comprises at the most 1% of an emulsifier to Improve the flow properties of the chocolate. Applicable emulsiflers
are mono-'and diglycerides, lecithin and also diacetyl tartaric esters of mono- and diglycerides.
The Danish patent application, DK A 9700390, describes the application of a citric acid ester of a monoglyceride as viscosity regulating emulsifler in chocolate. In the examples It Is described that the citric acid ester Is added to a compound, a vecao, and the plastic viscosity and the yield value are determined versus a soy lecithin reference.
Surprisingly, using a citric acid ester of a diglyceride in the present invention has turned out to be considerably more effective than conventional emulslfiers described In the art.
Furthermore, by using mixtures of citric acid esters of diglycerides and monoglycerides, an additionally Improvement has been achieved with still better results.
SUMMARY OF THE INVENTION
Accordingly, In a first aspect the present invention provides a method of producing chocolate, the method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxyllc acid ester of a diglyceride, to a chocolate mass, the carboxyllc acid not being tartaric acid. In a further aspect, the present Invention provides a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride, the carboxyllc acid not being tartaric acid. In particular, the carboxyllc acid ester of a diglyceride In the present Invention Is a citric acid ester of a diglyceride, preferably added to the chocolate mass before or during conchlng.
DETAILED DESCRIPTION OF THE INVENTION
One object according to the present Invention Is to obtain a reduction and/or a control of the flow properties including the plastic viscosity and the yield value, which will Imply a number of advantages. When using a carboxylic acid ester of a diglyceride, such as a citric acid ester of a diglyceride, It Is possible to reduce the total fat content in the chocolate and still keep flow properties known from chocolate containing high fat content. This ensures economic advantages by reducing the costs of cocoa butter, but also by reducing the fat energy percentage In the chocolate.
In addition to the above mentioned advantages, another object is to obtain process advantages owing to the fact that a reduction/adjustment of the viscosity and the yield value of the melted chocolate will make It far more easy to mould the chocolate in bars or figures. Also, the use of chocolate as couverture, enrobing fillings, nuts, etc may be easier.
Chocolate moulded, generally may be somewhat more viscous than coating chocolates since the chocolate may be vibrated into a mould over a longer period of time than allowed In enrobing.
Furthermore, the use of a carboxyllc acid ester of a diglyceride, such as a citric acid ester of a diglyceride, ensures homogeneity between the Individual productions securing a uniform quality of the chocolate products.
Another advantage of the present invention may be the emulsifier's effect on the temper of the chocolate compared to other emulslflers used in chocolate , i.e. the crystallization of the cocoa butter. The emulsifler of the present invention ensures easy formation of, and a high fraction of, the correct crystallization form of the cocoa fat, as this may be important for the texture and for the organoleptic qualities of high quality chocolates. Also, considerations must be made to the fact that the crystallized article will shrink in the moulds, which means that there is a need for easy release from the moulds.
Thus, the present invention relates to a method of producing chocolate, the method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxyllc acid ester of a diglyceride to a chocolate mass, the carboxylic acid not being tartaric acid.
In the present context, It should be understood that "chocolate" relates to what Is traditionally regarded as "real chocolate" and so called "compounds", which are chocolate Imitations. Thus, the term "chocolate" in the present context may comprise cocoa mass, cocoa fat and sugar. Cocoa fat accordingly should be Interpreted as being selected from the group consisting of cocoa butter, cocoa butter substitute, cocoa butter equivalent, cocoa butter replacer, and any mixture thereof such as used In the application of vecao.
Additionally, the chocolate mass may comprise a milk additive. The chocolate mass may additionally comprise any other additive to alter the physical or chemical properties of the chocolate, such as non-fat cocoa solids, sugar substitutes, natural and artificial flavors (e.g., vanillin, spices, coffee, ethyl vanillin, salt, brown nut-meats, natural vanilla, etc., as well as mixtures of these), antloxldants (e.g., preservatives such asTBHQ, tocopherols and the like), proteins, and the like. It follows that "chocolate mass" Is a mixture of the Ingredients in "chocolate", and the two terms should be Interpreted in the same way in the context of the present invention.
The process of making chocolate is reviewed In B. L. Zoumas and E. J. Flnnegan, "Chocolate and Cocoa", Klrk-Othmer Encyclopedia of Chemical Technology, Vol. 6 (3rd Ed.,
Wiley-Interscience, New York) 1-19 (1985). Some of the considerations present in the production of chocolate are described below, though a person skilled in the art Is aware of considerations not explicit mentioned in the text.
During the production of chocolate, the chocolate mass undergoes a mechanic conching process. The mechanical conching process takes place after the Ingredients have been well mixed and the chocolate mass subsequently has been rolled. During conching, the chocolate mass obtains Its physical properties and characteristic aroma. The crumbled chocolate mass Is subjected to an intensive mixing ensuring that all dry particles are coated by fat, thus converting the chocolate mass to a liquid suspension with solid coated sugar particles, which gives the chocolate a good smooth texture when eaten. A mixing-kneading process allows moisture and volatile components to escape while smoothing the chocolate paste and is critical to the flavour and texture development of the chocolate.
Alternatively to the conching step, a liquefying step mixes refined flakes under high shear over a short period of time. The refined flakes are quickly converted to a suspension of solids in a continuous fat phase. The lack of flavour development can be corrected by pretreating the liquor and cocoa butter.
Additional fat and emulslfiers are then traditionally added in the standardizing or finishing step to adjust viscosity to final specifications.
The final step in obtaining the desired rheology of the chocolate Is tempering, a process of Inducing satisfactory crystal nucleatlon of the liquid fat in the chocolate. If the chocolate Is Improperly cooled, the resulting chocolate will have a grainy texture as well as poor color and appearance.
Finished chocolate is a suspension of very fine particles (usually less than 50 microns) in fat. The particles usually consist of cocoa solids and crystalline sucrose as well as milk solids in the case of milk chocolate. The cocoa solids In the chocolate liquor and the milk solids have normally been processed so that they are fine enough to be Incorporated Into a chocolate mixture. Sucrose, however, requires considerable size reduction since extra fine grade sucrose, for example, typically varies in crystal size from about 40 to 1000 microns. To fulfil the function as an ingredient in chocolate, therefore, these sucrose crystals should be reduced In size to less than about 50 microns.. It is known that at least about 50% of the surface area of particles in milk chocolate are produced by the presence of particles below two microns In size. The presence of these ultra fine particles Increases viscosity and Increasing amounts of fat, e.g., cocoa butter, are required to coat such particles In order for the chocolate to flow properly In manufacturing operations.
It is well known in the art that the amount of fat present in chocolate will affect the flow properties of the chocolate, I.e., the addition of fat to a chocolate decreases both the yield value and the plastic viscosity. Consequently, fat content may therefore be varied according to the intended use.
Chocolates contain a very large amount of small sugar particles. Fat does not cover the surface of the sugar particles very easily and consequently, anything which will form an interface between the sugar and fat will aid in the flow of the chocolate. Emulsifiers, may produce such an Interface by coating the surface of the solid particles, In particular, the sugar. Thus, an emulsifying agent may be added to the chocolate mass.
In the present invention carbohydrate sweeteners, In the following termed sugars, with varying degrees of sweetness intensity are useful as additives In the preparation of chocolate and may be any of those typically used In the art. These sugars include, but are not limited to, sucrose, (e.g., from cane or beet), dextrose, fructose, lactose, maltose, glucose syrup solids, corn syrup solids, invert sugar, hydrolysed lactose, honey, maple sugar, brown sugar, molasses and the like. The nutritive carbohydrate sweetener, preferably sucrose, will be present in the chocolate as crystals or particles.
Particle size of Ingredients Is also known to influence the viscosity of chocolate. As a general rule, viscosity will Increase with decreasing particle size. An excess of fine particles below 5 microns whether derived from the sugar, milk, or chocolate liquor/powder component, will make the chocolate extremely thick and difficult to manage during pumping, depositing, and enrobing operations. Coarse particles which exceed 60 microns will tend, however, to give the chocolate a gritty sandy texture which Is unacceptable to consumers. Preferably, the particle size is around 20 microns, but In some applications it is suitable with particles in the range between 20 to 60 microns.
To ensure the right flow properties of the chocolate in the present invention, a chocolate emulsifying agent Is added to the chocolate mass. The term "chocolate emulsifying agent" should be Interpreted as an emulsifying agent applicable In chocolate, which is able to alter the flow properties of the chocolate mass and which Is edible. An emulsifying agent In the following Is abbreviated an emulslfier.
The emulslfier Is preferably gdded during conchlng of the chocolate mass according to the present Invention. Depending on the composition of the chocolate, the emulslfier may be added In the beginning of the conching. The emulslfier alternatively may be added in one or more doses while conchlng or It may be added in the end of the conching, for example If the viscosity of the chocolate mass should not be lowered too much. Alternatively, the
emulsifier may'be added to the chocolate mass before conching. This addition may have some advantages, for instance practical advantages.
Preferably, the emulsifier of the present Invention Is a carboxylic acid ester of a diglyceride, the carboxylic acid not being tartaric acid, more preferably the emulsifier is a hydroxy carboxylic acid ester of a diglyceride, more preferably the carboxylic acid is a hydroxy tricarboxylic acid ester of a diglyceride and most preferably the emulsffier is a citric acid ester of a diglyceride. Tartaric acid is not comprised in the group of carboxylic acid ester of a diglyceride and for brevity, the following text does not disclaim tartaric acid, though it should be understood as such.
To ensure the right emulsion, the emulsifier preferably comprises at least 10% wt. of a carboxylic acid ester of a diglyceride In the present invention. Alternatively, the emulsifier comprises at least 20% wt. of a carboxylic acid ester of a diglyceride, such as at least 30% wt., 40% wt., 50% wt., 60% wt., 70% wt., 80% wt., 90% wt., or at least 95% wt.
In particular, the emulsifier comprises at least 11% wt., 12% wt., 13% wt., 14% wt., 15% wt., 16% wt., 17% wt., 18% wt., 19% wt. of a carboxylic acid ester of a diglyceride, or at least 21% wt., 22% wt., 23% wt., 24% wt., 25% wt., 26% wt., 27% wt., 28% wt., 29% wt. of a carboxylic acid ester of a diglyceride, or at least 31% wt., 32% wt., 33% wt., 34% wt., 35% wt., 36% wt., 37% wt., 38% wt., 39% wt. of a carboxylic acid ester of a diglyceride, or at least 41% wt., 42% wt., 43% wt., 44% wt., 45% wt., 46% wt., 47% wt., 48% wt., 49% wt. of a carboxylic acid ester of a diglyceride, or at least 51% wt., 52% wt., 53% wt., 54% wt., 55% wt., 56% wt., 57% wt., 58% wt., 59% wt. of a carboxylic acid ester of a diglyceride, or at least 61% wt., 62% wt., 63% wt., 64% wt., 65% wt., 66% wt., 67% wt., 68% wt., 69% wt. of a carboxylic acid ester of a diglyceride, or at least 71% wt., 72% wt., 73% wt., 74% wt., 75% wt., 76% wt., 77% wt., 78% wt., 79% wt. of a carboxylic acid ester of a diglyceride, or at least 81% wt., 82% wt., 83% wt., 84% wt., 85% wt., 86% wt., 87% wt., 88% wt., 89% wt. of a carboxylic acid ester of a diglyceride, or at least 91% wt., 92% wt., 93% wt., 94% wt., 95% wt., 96% wt., 97% wt., 98% wt., 99% wt. of a carboxylic acid ester of a diglyceride.
In addition to the carboxylic acid ester of a diglyceride, the emulsifier may comprise a further emulsifying agent. This further emulsifying agent Is selected from the group consisting of a carboxylic acid ester of a monoglyceride, a carboxylic acid ester of a diglyceride, a phospholipid, a phosphollpld derivative, a polyglycerol ester of polyriclnolic acid, an ammonium phosphatide and any combination thereof. Phospholiplds may preferably be lecithin.
In another embodiment this further emulsifying agent may be lecithins enriched in either phosphatldyl choline or phosphatldyl ethanolamlne or both, mono- and dlglycerides, diacetyl tartarlc acid esters of mono- and diglycerides, monosodium phosphate derivatives of mono- and diglycerides of edible fats or oils, sorbitan monostearate, polyoxyethylene sorbltan monostearate, hydroxylated lecithin, lactylated fatty acid esters of glycerol and propylene glycol, polyglycerol esters of fatty acids, propylene glycol mono- and dlester of fats. In addition, other emulsifiers that can be used in the present invention, include ammonium salts of phosphatidic acid, sucrose esters, oat extract, etc., any emulsifier found to be suitable in chocolate or similar fat/solid system or any blend provided the total amount of emulsifier does not exceed 1% by weight.
Thus, any combination between the carboxylic acid ester of a diglyceride and a further emulsifying agent Is comprised in the present invention. This combination may be between the carboxylic acid ester of a diglyceride and one, two, or more of the further emulsifying agents. For example the combination may be a carboxylic acid ester of a diglyceride and a further carboxylic acid ester of a monoglycerlde. The selection of a suitable further emulsifying agent may depend on the required flow properties In the final chocolate product.
Accordingly, the further emulsifying agent may be added to the chocolate mass up to the missing amount of emulsifier. If e.g. the carboxylic acid ester of a diglyceride Is added in an amount of 10% wt., then the further emulsifying agent may be added in an amount of up to 90% wt. If a further emulsifying agent is added to the chocolate mass, the further emulsifying agent may comprise up to 90% wt. of the chocolate mass In any Individual specified amount. On the other hand if the carboxylic acid ester of a diglyceride is added in an amount of 20% wt., the further emulsifying agent may comprise up to 80% wt. of the added emulsifiers, etc.
Preferably, the further emulsifying agent in the present Invention is a carboxylic acid ester of a monoglyceride. The carboxylic acid ester of a monoglycerlde may preferably be a hydroxy carboxylic acid ester of a monoglycerlde, and most preferably be a citric acid ester of a monoglyceride.
In a presently preferred embodiment, the chocolate emulsifying agent essentially consists of a carboxylic acid ester of a monoglyceride and a carboxylic acid ester of a diglyceride. A presently more preferred embodiment of the Invention Is to add a citric acid ester of a diglyceride and as a further emulsifying agent add a citric acid ester of a monoglyceride.
Accordingly, In a useful embodiment the chocolate emulsifying agent essentially consists of a citric acid ester of a monoglyceride and a citric acid ester of a diglyceride. When using the term "essentially", it Is understood In the art that the purity of the fractions may never be 100%. There may be contaminants or other residues in the fractions, such as triglycerldes, free glycerols, etc.
In one presently preferred embodiment, when the chocolate essentially consists of a carboxylic acid ester of a diglyceride and a further emulsifying agent, such as carboxylic acid ester of a monoglyceride, the carboxylic acid ester of a diglyceride preferably is In the range of 30 to 90% wt., more preferably 40 to 90% wt., still more preferably 50 to 90% wt., still more preferably 50 to 80% wt., still more preferably 50 to 70% wt, most preferable 50 to 60% wt. such as around 50% wt.
Thus, the ratio between carboxylic acid ester of a diglyceride and a further emulsifying agent, such as carboxylic acid ester of a monoglyceride, comprising the emulsifier is from 3:7 to 9:1, more preferably from 4:6 to 9:1, still more preferably from 1:1 to 9:1, still more preferably from 1:1 to 8:2, still more preferably from 1:1 to 7:3, most preferable from 1:1 to 6:4, such as around 1:1. Disregarded In the ratios are contaminants, other residues in the fractions, or free fatty acids such as triglycerldes, free glycerols, etc.
The emulsifier applied in the present invention may be derived from a natural occurring fatty acid or derivatives thereof. The naturally occurring fatty acids may be selected from the group consisting of rapeseed oil, castor oil, maize oil, cottonseed oil, olive oil, palm oil, safflower oil, sesame oil, soybean oil, sunflower oil, and any mixture thereof and any derivative thereof. Preferably, the fatty acid is rapeseed oil or a derivative thereof. It should though be understood that the fatty acids might be derived from other sources in the present invention.
In the presently most "preferred embodiment, the emulsifier Is derived from rapeseed oil or a derivative thereof.
The carboxylic acid ester applied In the present invention preferably Is derived from naturally occurring fatty acids with iodine values of at least 45. Alternatively, the iodine value of the fatty acids Is at least 55, preferably around 55. Characteristic to the fatty acids Is that the esterlflcatlng fatty acids preferably are saturated or unsaturated fatty acids with 14 to 18 carbon atoms, more preferably with 16-18 carbon atoms. As an option the esterificating fatty acids are saturated or unsaturated fatty acids with up to 22 carbon atoms, such as up to 20 carbon atoms. The carboxylic acid ester of a diglyceride preferably has a saponlficatlon value of between 260 to 330, more preferably between 300-330. The
carboxyllc acid ester of a diglyceride furthermore preferably has an acid value of between 10-80, more preferably between 50-70.
In order to produce a chocolate with acceptable flow properties, it is also essential to keep the moisture content low.
It is well known within the chocolate industry that moisture content has a significant effect on the flow properties of chocolate. If water is added to chocolate, a marked increase in viscosity occurs. It has been previously reported that both the yield value and plastic viscosity Increase with moisture levels above 1.1%. Between 0.6-1.1% moisture, the plastic viscosity is nearly constant whereas the yield value rises with Increasing moisture. This could be explained by the formation of layers of syrup on the surface of sugar , particles with an Increase in moisture, which increases the friction between the said particles.
The most preferred carboxylic acid ester in the present invention, citric acid ester of a diglyceride, may be prepared by a reaction between citric acid and diglyceride. The ratio between the reactants, the reaction temperature and the reaction time Is determining the degree of esterfication. Diglyceride traditionally is prepared by trans esterflcation of triglycerldes with glycerol, by the invention is though not limited to this reaction.
Heating the mixture of the prepared diglyceride and citric acid performs the esterlficatlon to give the citric acid ester of diglyceride. Diglyceride may be preheated before the addition of citric acid, and then the heating preferably Is continued until reaction temperature Is obtained. The temperature of the preheated diglyceride may generally be 80°C to 120°C and preferably 90°C to 110°C and more preferably 100°C. The reaction temperature may generally 100°C to 160°C and preferably 120CC 150°C and more preferably about 140°C. The reaction mixture Is typically maintained at a pressure of 10 to about 760 mmHg and more preferably maintained at a pressure form about 20 to 200 mmHg and most preferably about 50 mmHg.
Prior to and/or during the reaction, the reaction mixture may advantageously be covered with an Inert gas such as nitrogen. The water being released during the reaction may continuously be removed from the reaction mixture by evaporating and condensing the water vapour.
The weight ratio of citric acid to diglyceride In the reaction mixture broadly may range from 1:10 to about 1:2. Preferably the weight ratio Is from 1:10 to about 1:4 and more preferably about 1:5.
Generally, the esterificatlon reaction may be performed for about 1-20 hours and preferably 5-10 hours and more preferably 8-10 hours.
Conchlng for extended periods of time (longer than 4 hrs.) at elevated temperatures (above 100 DEG F.) is well known to be an effective method for removing water and offlavours from chocolate paste. The initial ingredients should be selected to have low moisture, and chocolate processing should be done so that moisture uptake from the atmosphere by hygroscopic ingredients Is kept to a minimum.
The addition of chocolate emulsifying agents in the present Invention is in the amount of between 0,2 to 1,0% wt. of the chocolate mass, more preferably between 0,4 to 0,8% wt., most preferably between 0,5 to 0,6% wt. The amount of added emulsifier depends for Instance of the flow requirement of the chocolate mass.
The chocolates of the present Invention may contain a trace of water. It Is preferred that they contain less than 1% moisture, preferably less than 0.75% by weight, in order to meet the flow requirements. Higher moisture is very detrimental to the yield value and plastic viscosity.
Finally, the second aspect of the present Invention is a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxyllc acid ester of a diglycerlde. The composition Is provided by the present method according to the invention and thus all features and embodiments as described In the text above can be combined in all relevant ways with the second aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig.l is a comparison of functionality as Yield Value and Plastic Viscosity for citric acid esters with different monoglycerlde percentage. The prepared citric acid esters are also compared with two commercial citric acid esters from the marked.
Fig.2 is a comparison of functionality as Yield Value and Plastic Viscosity for mixtures of citric acid ester of monoglyceride and citric acid ester of diglyceride.
Fig.3 Is a comparison of functionality as Yield Value for different dosage of different citric acid esters.
Fig.4 Is a comparison of functionality as Plastic Viscosity for different dosage of different citric acid esters.
Fig. 5 is a comparison of functionality as Yield Value and Plastic Viscosity for different citric acid esters In Compound.
Fig. 6 Is a comparison of functionality as Yield Value and Plastic Viscosity for different citric acid esters made In pilot scale.
EXAMPLES
A general procedure for determining the yield value and plastic viscosity in chocolate.
The functionality of the citric acid esters in chocolate was determined by measure of yield value and plastic viscosity. The measure was made on a Haake Viscometer RV1 by a rotor-cup system. The rotor was a Z38 DIN53018.
After the measure, the yield value and plastic viscosity were determined by the use of the rheology casson-model.
Example 1: Citric acid esters with variation of the ratio of monoglyceride and diglyceride.
Glycerides In varying ratio of monoglyceride and diglyceride were charged to a reaction flask. The reaction flask was equipped with a mechanical stlrrer, nitrogen Inlet, vacuum capabilities to 1 mmHg, steam outlet, thermometer and temperature controlled heating mantel.
The glycerides were heated until 100°C with good agitation. Citric acid, 20% In weight, was added to the glycerlde, and then the heating was continued until 140CC. After the addition of citric acid, the pressure in the reaction flask was gradually reduced to 50 mmHg. The reaction was continued for 5 hours. Then the reaction mixture was cooled to below 80°C before discharge.
After the completion of the reaction, the resulting citric acid esters were analysed for functionality In a milk chocolate. The result of the analyses of functionality are summarised In the below table 1 and fig. 1. MG Is the fraction of monoglyceride, and positive signs in last two columns mean a better result compared to the reference compound Lecithin.
In figure 1, a number of measurements of the plastic viscosity are stated In a 32% chocolate In which the ratio of monoglyceride and diglyceride Is from 98/2 to 5/95. From the measurements it appears that the 98/2 diglyceride citric acid ester gives a much
better, I.e. lower, plastic viscosity compared to the citric acid ester of monoglyceride, where the mono percentage at the distillation is exceeding 90%.
It Is particularly interesting to observe the functionality (the efficiency) of different citric acid esters of mono- and diglycerides, when changing the proportion between the two glycerides that the efficiency of the emulsifiers increases with an optimum at approximately a 1:1 mixture of the two glycerides. When exceeding the 50% monoglyceride moiety content, the functionality of the esters rapidly decreases with increasing content of monoglyceride.
For diglycerides of a commercial purity of minimum 98% diglyceride and a maximum of 2% monoglyceride as an unavoidable contaminant, the corresponding citric acid ester derivative thus has shown to be surprisingly efficient reducing both viscosity and yield value in a chocolate mass. The reduction is In the order of between 0.5 to 1 time compared to traditionally applied emulsifiers, such as soy lecithin.
By way of comparison, some single values from tests with citric acid esters of monoglycerides are shown in the form of two commercial products: Citrem 211 and Citrem 5010. The same picture is observed at analogue tests of the citric acid esters, as stated above, but by choosing other types of chocolate, for example pure bitter, and rich in fat, and compounds. Obviously citric acid esters based on diglycerides or up to 50/50 mixtures with monoglycerides give a good reduction of both the plastic viscosity and of the yield value of chocolates and compounds. At a higher ratio of the including monoglyceride the efficiency decreases.
Table 1:

(Table Removed)

Example 2: Mixtures of a citric acid ester of a monoglyceride and a citric acid ester of a diglyceride, with variation of the ratio.
A citric acid ester of a monoglyceride (96%) and a citric acid ester of a diglyceride (97%) were made according to Example 1. From the two citric acid esters, mixtures with a varying ratio of monoglyceride and diglyceride were separately mixed In a reaction flask. The reaction flask was equipped with a mechanical stlrrer, a nitrogen Inlet, a thermometer and temperature controlled heating mantel. The mixtures were heated until 80°C, when good agitation. After 5 mln. of agitation at 80°C, the mixtures were discharged. After the completion of the mixing, the resulting citric acJd esters mixtures were analysed for functionality In a milk chocolate. The result of the analyses of functionality are summarised In the below table 2 and fig. 2. MG is the fraction of monoglyceride, and positive signs In last two columns mean a better result compared to the reference compound Lecithin.
Table 2:

(Table Removed)

Example 3: Functionality of citric acid esters, with different dosage, in chocolate.
A citric acid ester of a monoglyceride (96%), a citric acid ester of a dlglyceride (97%) and a citric acid ester of 50% monoglyceride and 50% diglycerlde, were made according to Example 1. A typical commercial lecithin was used as the reference compound. Functionality of different dosage of the citric add esters was determined In a milk chocolate, then compared with the reference compound. The result of the analyses of functionality Is summarised In the below table 3 and figure 3-4. MG is the fraction of monoglyceride, DG Is the fraction of diglycerlde, and positive signs in last two columns mean a better result compared to the reference compound Lecithin.
In the present example It has been demonstrated that the esterlfication with the citric acid can be done on the pure components, I.e. diglycerlde and monoglyceride. Esterlfication can also be done as prebelended mixtures of the two types of glycerides. No difference in the functionality of two corresponding formulations Is observed. Thus, the dlglycerides can e.g. be produced as a residue fraction (heavily boiling) from the distillation of the monoglycerides (light boiling). The monoglyceride citric acid ester can then be mixed in the required ratio to obtain the optimal point as to the functionality.
In a more rational way the esterificatlon can also be done on the mono- and diglycerlde, i.e. the equilibrium mixture being normally available as a raw material from which the monoglyceride is distilled. This considerably simplifies the process. Costly and complicated distillation of the monoglyceride Is avoided, Implying that one process step Is eliminated before the esterificatlon with the citric acid, a fact which renders the process more

attractive on a economical point of view than it will be by using the solution with the distilled monoglyceride.
Table 3:

(Table Removed)
Example 4: Temper ability of milk chocolate, Lecithin versus citrlc-acld-ester
Chocolate test system
A standard milk chocolate system Is chosen as the chocolate model system to demonstrate in any of the tested emulslfiers Is affecting the tempering application of chocolate. The total fat content is around 32% wt. fat, and the amount of whole milk powder is 23% wt. Particle size of the milk chocolate Is max 25 micron. Since milk chocolate Is the most difficult type of chocolate to temper, this is the system that is chosen. It is tested If It is possible to temper all milk chocolates (added different emulslfiers) to a practical and producible state and furthermore If some of the emulslfiers course changes in the temperature settings needed to obtain a well tempered chocolate.
Equipment
Palsgaard is using a Aasted AK-10 pilot plant tempering machine to conduct the tempering process. For evaluation of the degree of temper a Exotherm 7400 is used. The cooling cell of the temper-meter Is set at 8,0°C.
Temper table comments
In order to understand the Information given in table 4, some comments must follow. The column saying "State at temperature 21.5°/20.7°/29.5°C" Is the start temperature for all the measurements. Slightly under tempered is better than under tempered (better meaning less influence at the cocoa butter crystallisation). The following Information about Inflexion at different temperatures It is desirable to get Inflexion (cocoa butter crystal formation) at as high a temperature as possible. So the perfect outcome would be If all Inflexions came at 22°C (or at higher temperatures).
Conclusion
All the 4 emulslfier can be tempered at both 0,60 and at 1,0% without any serious difficulties, but of the four tested emulsiflers, the citric acid ester of dlglyceride is found to be the easiest to temper. There is a general tendency in all the 4 tested emulsiflers and that is that they all are slightly easier to temper at 0,60% compared to 1,0% dosage. Also slightly colder water settings should be selected at the high emulsifler dosage In order to obtain good Inflexion curves this is another Indication of a beginning Influence of the crystallisation of the chocolate fat phase.
Through measurements of the chocolate's temper the additive's effect on the crystallization conditions can be evaluated, as the object is to obtain a clear Inflextion at 22°C or higher. Measurements of a chocolate's temper by adding of diglyceride citric acid

ester to a chocolate have proved that the chocolate becomes only a little undertempered, whereas a clear undertempering is observed when using lecithin, At the same time it is found that a dosage of 0,6% of diglyceride citrate gives the best tempering.
Table 4:

(Table Removed)
Example 5: Functionality of citric acid esters In compound.
A citric acid ester of monoglyceride (96%), a citric acid ester of dlglyceride (97%) and a citric acid ester of 50% monoglyceride and 50% diglyceride, were made according to Example 1. A typical commercial lecithin was used as the reference compound. Functionality with dosage at 0,6% of the citric acid esters was determined in a compound with Palm Olein as fat base. The fat percent was approx. 30. Lecithin was used as reference material. The result Is summarised in the below table 5 and figure 5. Negative sign in the last two columns mean a bad result compared to the reference material Lecithin.
Table 5:
(Table Removed)
Example 6: Citric acid esters of monodiglyceride In pilot scale.
A monodiglyceride (40kg), with the composition of 43% monoglycerlde, 42% diglyceride and 15% trtglycerlde, was charged to a reaction vessel. The reaction vessel was equipped with a mechanical stlrrer, nitrogen Inlet, vacuum capabilities to 50 mbar, steam outlet, thermometer and temperature controlled heating system. The glycerlde was heated until 100°C, under good agitation. Citric acid (10kg) was added to the glyceride, and then the heating was continued until 140°C. After the addition of citric acid, the pressure In the reaction flask was gradually reduced to 90 mbar. The reaction was continued for 12 hours. Then the reaction mixture was cooled to below 80°C before discharge. After the completion of the reaction, the resulting citric acid esters were analysed for functionality in a milk chocolate. The result of the analyses of functionality Is summarised in the below table 6
and figure 6. Negative sign, in last two columns, means a bad result compared to the reference compound Lecithin.
Example 7: Citric acid esters of diglyceride in pilot scale.
A diglyceride (42kg) with the composition of 4% monoglyceride 91% diglyceride and 5% triglycerlde was charged to a reaction vessel. The reaction vessel was equipped with a mechanical stirrer, nitrogen inlet, vacuum capabilities to 50 mbar, steam outlet, thermometer and temperature controlled heating system. The glycerlde was heated until 100°C, under good agitation. Citric acid (10,5kg) was added to the glycerlde, and then the heating was continued until 140°C. After the addition of citric acid, the pressure In the reaction flask was gradually reduced to 90 mbar. The reaction was continued for 9 hours. Then the reaction mixture was cooled to below 80°C before discharge. After the completion of the reaction, the resulting citric acid esters were analysed for functionality In a milk chocolate. The result of the analyses of functionality is summarised in the below table 6 and figure 6. Negative sign, In last two columns, mean a bad result compared to the reference compound Lecithin.
Table 6:
(Table Removed)

The invention relates to a method of producing chocolate. The method comprising adding a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride to a chocolate mass, the carboxylic acid not being tartaric acid. The invention also provides a chocolate composition comprising a chocolate emulsifying agent comprising at least 10% wt. of a carboxylic acid ester of a diglyceride, the carboxylic acid not being tartaric acid. In particular, the carboxylic acid ester of a diglyceride in the present invention is a citric acid ester of a diglyceride, preferably added to the chocolate mass before or during conching.