GB2410172A - Chocolate flavour extract - Google Patents

Abstract

An extraction of chocolate flavour from low-fat chocolate powder, using an aqueous organic solvent to produce a highly water soluble chocolate flavour extract. This chocolate flavour extract may be in the form of a powder or a concentrated liquid and can be used in the manufacture of chocolate flavoured foods and beverages. The extractant is preferably a mixture of ethanol and water.

Description

CHOCOLATE FLAVOUR EXTRACT

Field of the invention

This invention relates to the extraction of chocolate flavour from chocolate powder with solvents.

Background of the invention

The conventional chocolate-making procedures are described in books like "Industrial Chocolate Manufacture and Use" edited by S. T. Beckett, (Third Edition, 1999, Blackwell Science) or "Chocolate, cocoa, and confectionery: Science and technology" edited by B. W. Minifie (Third

Edition, 1989, Van Nostrand Reinhold). In summary,

chocolate-making procedures use mixtures of cocoa, (i.e. could be cocoa liquor, cocoa powder, and/or cocoa butter) sugar (but not limited to sucrose and/or sugars substitutes such as polyols), emulsifiers (i.e. lecithin), vanilla or vanillin; for dark chocolate and with the addition of milk ingredients (i.e. whole milk powder semi-skimmed milk powder, skimmed milk powder, whey, casein and caseinates); for milk chocolates. Milk chocolate may be made by mixing the relevant individual powder ingredients including milk powder or by using the crumb process. In the crumb process milk is evaporated to about 30-40% solids, mixed with sugar and condensed under vacuum with rapid boiling at a maximum temperature of 75C until a concentration of about 90 solids whereby there is some sugar crystallization. This is then kneaded with cocoa liquor for about 20 minutes in a stiff magna is produced with additional crystallization.

The paste is then dried in vacuum ovens. The dried crumb is then milled and mixed with cocoa butter and refined, in very much the same way as the non crumb powdered milk chocolate. The refined chocolate mixture is then couched and tempered.

Depending on the origin and degree of fermentation of the cocoa beans, and processes (i.e. roasting and couching) chocolate flavour is developed. During roasting and couching, Maillard reactions take place and are very important contributors to the development of chocolate flavour. They involve a type of non-enzymatic browning which is a reaction between reducing sugars (carbonyl groups), amino acids and short peptides (free amino groups).

Fermentation, an early step in the processing of cocoa beans, is important to the development of suitable flavours and/or flavour precursors it is well known in the art that flavour in the final cocoa or chocolate is closely related to fermentation.

Roasting is one of the most important stages in the development of flavour. The process involves heating the beans to 110-220 C depending on the bean type and is needed for the reduction of moisture, release of the shell and development of chocolate flavour. One of the most important reactions during the roasting process is the non-enzymatic browning or Maillard browning (see Beckett pp 107). This complex reaction usually between free amino acids and reducing sugars has an important role in the flavour development. The roasting generates high quantities of free amino acids and high quantities of flavour precursors.

Conching can be described as the working of chocolate making ingredients into a fluid paste, with certain recipes this may include crumb and/or refiner flake and/or chocolate powder. Not only does couching allow very efficient mixing of the chocolate mass, it is also very important in the modification of flavour. Typically, couched chocolate is described as having a "mellow" chocolate flavour compared to unconched products in which the flavour of cocoa (and sugar if present) predominates.

As the moisture is removed during the couching process, it takes away many of the unwanted flavour components. In this way approximately 30% of acetic acid, up to 50% of low boiling aldehydes are volatized and most short-chain volatile fatty acids (see Beckett pp 113). In fact up to 80% of the volatiles are removed in the first hours of the couching process (see Beckett pp 113 & 117).

Conching of milk chocolate usually takes place at temperature of 45-70 C and of dark chocolate at temperature of 50-90 C although for creation of caramelisation notes temperatures of 45-75 C are necessary depending on time and type of sugar.

Investigations in flavour development suggest that the Maillard reaction is not complete at the end of the roasting process, and continues during couching (Ziegleder et al. Deutsche Lebensmittel Rundschau, 1982, 78(9), 315- 318). Further investigations have confirmed that chemical changes occurred during the couching process (Counet et al. J. Agric. Food Chem. 2002, 50, 2385-2391).

Conched chocolate powder can be obtained according to US 5882709. The process provides a method for production of a chocolate reduced in fat, which either contains sugar or is free of added sugar, and which has the taste and mouth feel of traditional chocolate. The process involves developing the chocolate flavour during a conventional chocolate-making procedure up to and including couching, and includes a step where the fat is removed by means of a cocoa liquor press. The resulting pressed cake is then broken up and nibbled into small pieces of about 10 mm diameter which are further milled to reduce the particle size. During this size reduction, a cryogenic system as well as cooling air may be required for turbine or pin mills when the chocolate being milled has a total fat content of more than 12% by weight. A separate air classifier is used after turbine or pin milling to remove fine particles of less than 5 m. A second air classifier is used to remove particles having a size of greater than m. For an air classifier, it is generally necessary to use cooled process air (typically at 0 C) in the case where the chocolate composition contains more than 15% total fat.

Processes described in US 2823124 and US 3579349 obtain cocoa flavour extracts by extracting cocoa products with water. The flavoured extract produced by this process, being completely water-soluble, is used in different beverages (milk, carbonated drinks, eta) and in many culinary applications.

EP 1139792 describes a method to obtain an aroma concentrate from cocoa, using a solid liquid extraction followed by a perevaporation technique. The patent describes and compares various extraction methods.

EP 1253200 Al reports a method for the production of cocoa and chocolate flavour based on polypeptide content.

The polypeptides and/or their fragments can be used in a process reaction with reducing sugars to produce chocolate flavour.

GB 2370213 A details a method for manipulation of the chocolate flavour using flavouring reactions at various temperatures and ingredients at ambient pressure.

A disadvantage of previous attempts to produce a similar suitable extract is that cocoa flavour extract is produced, rather than a real chocolate flavour extract.

Cocoa extracts are bitter so the flavour has to be modified to be more "chocolatey" by addition of sugars and vanilla flavour.

Summary of the Invention

The present invention provides a method for producing a water soluble chocolate flavour extract comprising, a) mixing low fat chocolate powder with an aqueous organic solvent to produce a suspension of solids in a liquid, b) removing solids from the liquid and c) at least partially removing the solvent from the recovered liquid to leave a chocolate flavour extract.

This is a method to recover and concentrate the chocolate flavour from low fat chocolate powder.

This invention also covers a chocolate flavour extract produced as described above. The chocolate flavour extract can be used in the manufacture of chocolate flavoured comestibles such as beverages and foods. Therefore this invention also covers a chocolate flavoured food comprising the chocolate flavour extract according to the present invention. Such foods include yoghurt, custard, jelly and other desserts, confectionery products, milk and/or water- based beverages, ice-creams, biscuits, baked products, savoury and other culinary products.

Figures Figure 1 is a flow diagram showing the chocolate flavour extraction process of the invention.

Figure 2 shows extractions of flavour molecules from traditional chocolate (left) and low fat couched chocolate powder (right).

Detailed Description of the Invention

The method for producing a water-soluble chocolate flavour extract starts with low-fat, free-flowing chocolate powder. As used herein chocolate powder refers to a composition in which the cocoa powder, sugars and other chocolate making ingredients have been allowed to interact and develop a chocolate flavour. Such interaction occurs in a flavour development step such as couching or a reaction step of a flavour development process described in applicant's co-pending application filed on the same date hereas, agent's reference HMJ03775GB.

Conched chocolate powder has many advantages compared with traditional chocolate, and the flavour development is the same for both. Conched chocolate powder has the taste and mouth feel of traditional chocolate. The only difference between these chocolate products is the fat content.

Suitable chocolate powder for use in the present invention e.g. couched chocolate powder, has the following advantages. One of the more important properties is the very small size of the particles. This improves the contact area between the solvent and the solid particles, rendering the flavour extraction a more efficient process. Another important property is the low fat content, which is about compared with 25-40 for traditional chocolate.

Traditional chocolate is a fat medium in which the solid particles are distributed. The flavour molecules are found in the solid particles, in the non-fat components, and these particles being wrapped in fat makes their aqueous solvent extraction (e.g. water-alcohol) inefficient as shown in Figure 2. In couched chocolate powder, the low fat content offers better contact between particles and solvent, improving the flavour extraction.

The use of couched chocolate powder has other technical advantages in the extraction procedure. The chocolate flavours can be extracted at room temperature while with traditional chocolate; the sample has to be warmed up (minimum 30 C) to melt the chocolate before extraction. The fat present in traditional chocolate also gives problems in the extraction procedure because two liquid phases are present (water-alcohol and fat), making the separation more complex and expensive.

A low fat chocolate powder has a fat content of less than 22 or 20, preferably less than 12, more preferably less than 10%, still more preferably less than 5, even more preferably less than 2% by weight of the chocolate powder and still even more preferably is substantially fat free. Chocolate powders having a higher fat content will not be free flowing, instead the powder will start to clump into a paste with the result that subsequent mixing with an aqueous solvent is less efficient or requires higher shear forces to achieve the same results.

The low fat chocolate powder is mixed with an aqueous solvent to produce a suspension of solids in a liquid. The aqueous solvent may be water, or a mixture of water and a solvent selected from the group consisting of C14alkanol, C24 glycol, Ci 4 dialkyl ketone or C14 alkyl ester of C2 alkanoic acid. It is preferred that the aqueous solvent is a hydroalcoholic (alkanolic) solvent since alkanols are relatively volatile and extract a range of flavour components having very desirable flavour, as well as aroma.

It is preferred that the aqueous solvent is a mixture of ethanol and water although mixtures of methanol, which extracts more polar components such as salts, may be suitable at some proportions. Very beneficial results have been seen with the solvent comprising 40 to 80 ethanol by volume.

When the low-fat chocolate powder is mixed with the aqueous organic solvent, the aqueous solvent is present in a higher amount than the powder. For example the ratio of low-fat chocolate powder to aqueous solvent is between 1:2 and 1:25 w/v, preferably between 1:5 and 1:15 w/v.

Such ratios of low-fat chocolate powder to aqueous solvent, enables high yields of flavour extract to be obtained at room temperature. The skilled person will appreciate that carrying out the extraction process at room temperature has certain advantages. The mixing can also be carried out at higher temperatures which result in a higher efficiency and increased yield of chocolate flavour extract. The temperature should not be too high, however, because modifications of the flavour are likely to take place at higher temperatures which reduce the desired flavour properties of the extract. The mixing should occur at a temperature of 20 to 80 C, preferably at a temperature of 20 to 50 C, more preferably at a temperature of at least ambient, such as 20 C or more.

The extraction is suitably carried out in a stirred reactor and the agitation speed is adjusted to obtain a homogeneous blend. The pressure is usually atmospheric.

The extraction step for a high yield is between 3 h and 8 h depending of the temperature and the amount of solvent.

Once the low-fat chocolate powder and the aqueous solvent have been thoroughly mixed to produce a suspension of solids in a liquid and to transfer chocolate flavour molecules from the solids to the aqueous solvent, the solids are removed from the solvent. Filtration is suitably carried out in the same temperature range as the extraction. Additional heating or cooling is preferably avoided. The removal of the solids may occur by filtration, filtration under vacuum, centrifugation, solidliquid separation, Recantation or other appropriate process. A suitable filter size removes particles with size greater than 150m, preferably particles with size greater than 80pm. Filtration through a monoplaque filter under vacuum is preferred. Solvent loss is monitored during the extraction and the cake obtained in the solid-liquid separation contains about 25 of solvent in weight.

If full fat chocolate powder (which can be manufactured by cryogenic milling), were to be used there would be a problem with the filtration step. At raised temperature the filter becomes blocked as cocoa butter begins to melt at >25 C. With full fat chocolate powder the mixture would have to be cooled so that the fat would solidify and go to the surface and subsequently be removed.

The removed solids may be retained to undergo further rounds of the extraction process by mixing the removed solids with an aqueous solvent to produce a suspension of solids in a liquid. The extraction process can be carried out once, twice or three or more times and the filtrates are then combined usually before, but optionally after the concentration step. In each extraction the solvent ratio and time can be changed.

The liquid phase is then modified by at least partially removing the solvent to leave a chocolate flavour extract. Solvent removal may occur by concentrating and/or drying the liquid phase. Preferably the filtrates are combined and concentrated under vacuum (c150 mmHg) at 45-65 C. The vapours are condensed and the solvent recovered for further extractions. The concentrate may be dried, for instance in a tray vacuum oven (< 50 mmHg) at 50 C for 24 hours. The product foams perfectly in the trays. Solvent removal may alternatively be carried out by spray-drying, preferably using dispersion agents such as gum arabic and/or maltodextrin. For some applications addition of a flow agent to a powdered flavour extract is advantageous to optimise flow characteristics.

Removing the majority of the liquid solvent leaves a concentrated liquid chocolate flavour extract. This can be combined with a small quantity of liquid diluent to produce a liquid chocolate flavour extract. The preferred liquid diluent is propylene glycol and/or an aqueous sorbitol solution.

Alternatively, substantially all the aqueous solvent is removed to leave a solid chocolate flavour extract, which is preferably mechanically processed to produce a powdered chocolate flavour extract. The product may be a fine powder. This may be very hydroscopic and can be stabilised by addition of a small quantity of silicon dioxide, normally 0.5 pip. It has been found that vanillin or vanilla present in chocolate is removed with the fat part of the chocolate if fat is extracted from chocolate in the manufacture of low-fat chocolate powder.

Therefore vanillin and/or vanilla is/are optionally added to the chocolate flavour extract.

Both the powdered chocolate flavour extract and the liquid chocolate flavour extract have the advantages that they have a real chocolate aroma, flavour and colour and are highly soluble in water. This allows the extract to be readily used in foods and beverages and to impart a real chocolate flavour.

Whilst conventional (not low fat) chocolate powder is entirely soluble in water chocolate flavour extract is much more highly soluble in water (approximately more than ten times, using an ethanol/water mixture extraction solvent).

For example for plain chocolate powder 0.08 g/L soluble through 0.45pm filter, whereby the corresponding chocolate extract is 1 g/L soluble. In application in chocolate flavoured food and beverage products, the intense flavours hereby obtained is used either alone as the source of flavours or in combination with cocoa powder and/or conched chocolate powder.

Various low fat chocolate powders can be used in the process of the invention, usually conched chocolate powders, depending on which kind of chocolate flavour extract is wanted from the process. Different kinds of conched chocolate powders are available; white conched chocolate powder, milk conched chocolate powder and dark conched powder.

The final yield of the extraction is in between 10 to 55% in weight depending on the extraction conditions.

Example

kg of conched low fat chocolate powder ("extra- bitter" from a chocolate with 70% cocoa) was added to 350 L of ethanol:water (7:3,v/v), at room temperature. The mixture was stirred until a homogeneous mixture was obtained. The agitation continued for 2 h when the mixture was filtered under vacuum through a monoplaque filter. The cake was returned to the stirring reactor and a further 150 L of the same extracting solvent was added while continuously stirring. The extraction continued for 2 h, and the mixture was filtered again under vacuum through a monoplaque filter. This filtrate was combined with the first filtrate. The filtrate was concentrated at 55 C, 125 mmHg for 2 h. The concentrate weighed 73 kg, and was dried in a vacuum tray oven at 55 C and at pressure <50 mmHg.

The dry product weighed 17 kg, representing an extraction yield of 34% in weight. The product was milled in a pin mill, resulting in a fine brown powder, with a strong chocolate flavour. To avoid a highly hydroscopic product, 0.2 of silicon dioxide powder (food grade) was added. The product was fully soluble in water.

The powder was subjected to tests by a panel of 2 or 3 experienced testers who rated it for flavour and aroma on the scale very low - low - high. The handling characteristics and hygroscopicity were assessed. The results for this product are shown in the Table below as Runno. 2211.

Similar process steps were carried out in a range of materials and using a range of solvent mixtures. All powders used were the same as described above. For starting materials other than powders the natural (all low fat) were initially grand at low temperature before the extraction was initiated. Where the extraction system is indicated to be 'aggitation" this refers to the above described method. Where the extraction system is indicated to be 'recirculation" the method involves flowing the extractant through the raw material by peristatic pump action. The assessments of the products are shown in the

table below.

- 1. .... n 8 1 - 52 Ott i 3 == A it W,...$\ Q) al q) al _ in al c) Q) <; ,!,5 ,4.,., z=m ant, <. {\

3 3 3 3 A ( .8' 2' D, V, 3 t''; $so q>;, ' L) v 's'. ,,. _ C) O ^$;';. S-'v'.^< 3 3 3 3 3 ie,,,,.,. 0 0 0 0 0 30 o3 tt s. Q I >-vv. I /.' V >t.;, /.< , , E E E E E,E E E E E s s < . . o o o o ' 3 ' o!.,,s\ s. o o _ o i,. ot, s;<$,.vs 2 o 2 o.2 o.2 o 2 o s i-' s s <. - - /\V C) ()C oc C'c (3C V:5. s. . s, s q) Q) /,s, O O O O O =m o p E E E E E D:s s < _ w- = E Q E E E ;. .c < Oo o Oo Oo o E E E E E osss. . pA N N N o o o o o p _ C) ( c9 (5 0 Ir [] tY 9 5 9,, , ,Q, 5S5,5,A 5,5 5, a? \ \ O O O (D O O O O O 0 017} 9 5 + P 9 (0 00 CO a) 1 (0 O 1- V. \SAS/S\V.59 SS ' ) U N (' o _ s <. ., ; s 0 0 0 /5,p\,,< 0 e j:.s s. P tl' w t w 3 3 3 0' 55t't O!;S;e._ s > 9. s ' b.' s e A ^, O O O O O O a) s ' iPisks,s' 0 0 0 0 0 0 0 0 O j> '9'sosV., '' O O ^ O N - is. t.'..'.' N N N N N N N O I O ^ _ i< i,95,0, . I I I I I I I O G I t; o.;^.p,viX ^' " _ O _ O 0 0 0 iu 0O }t e Q) c a) a Q c) tD . oE :- oE oE oE E oE Eo oE =d - ,Q o.CL o 3333 333333 : ' .. 'St9 ' ' "

N O O N _ N

Claims (14)

1. A method for producing a water soluble chocolate flavour extract comprising, a) mixing low fat chocolate powder with an aqueous organic solvent to produce a suspension of solids in a liquid, b) removing solids from the liquid and c) at least partially removing the solvent from the recovered liquid to produce a chocolate flavour extract.

2. A method according to claim 1, wherein the removed solids from step b) undergo further steps d), e) f) and optional step g), comprising: d) mixing the removed solids with an aqueous solvent to produce a suspension of solids in a liquid, e) removing solids from the liquid, f) at least partially removing the solvent from the recovered to produce a chocolate flavour extract, and optionally g) repeating steps d), e) and f).

3. A method according to claim 1 or 2, wherein the ratio of low fat chocolate powder to aqueous solvent is between 1:2 and 1:25 w/v, preferably between 1:5 w/v and 1:15 w/v.

4. A method according to any one of the preceding claims, wherein the aqueous solvent comprises water and a solvent selected from the group consisting of C14 alkanol, C24 glycol, C14 dialkyl ketone or C14 alkyl ester of alkanoic acid, and is preferably ethanol.

5. A method according to claim 4, wherein the aqueous solvent comprises 40-80 ethanol by volume.

6. A method according to any one of the preceding claims, wherein the mixing step occurs at a temperature of 20 to 80 C, preferably at a temperature of 20 to 50 C.

7. A method according to any one of the preceding claims, wherein the chocolate powder has a fat content of less than 22%, preferably less than 20%, more preferably less than 12, still more preferably less than 10%, even more preferably less than 5, still even more preferably less than 2% by weight of chocolate powder and most preferably substantially fat free.

8. A method according to any one of the preceding claims, wherein the chocolate flavour extract is combined with a liquid diluent to produce a liquid chocolate flavour extract, preferably wherein the liquid diluent is propylene glycol and/or an aqueous sorbitol solution.

9. A method according to any one of claims 1 to 7, wherein substantially all the solvent is removed to leave a solid chocolate flavour extract and the solid extract is mechanically processed to produce a powdered chocolate flavour extract.

10. A method according to any preceding claim in which solvent is removed by evaporation, preferably at reduced pressure.

11. A chocolate flavour extract produced by a method according to any preceding claim.

12. Use of a chocolate flavour extract according to claim 11, in the manufacture of a chocolate flavoured comestible product.

13. A chocolate flavoured comestible product comprising a chocolate flavour extract according to claim 11.

14. A chocolate flavoured comestible product according to > claim 13, which is selected from yoghurt, custard and beverages.