WO2000002460A1

WO2000002460A1 - Chocolate production

Info

Publication number: WO2000002460A1
Application number: PCT/GB1999/002003
Authority: WO
Inventors: Frank Wilfred Earis
Original assignee: Mars (Uk) Ltd.
Priority date: 1998-07-10
Filing date: 1999-06-25
Publication date: 2000-01-20
Also published as: GB2339381A; AU4522199A; GB9815041D0

Abstract

There is disclosed a process for tempering chocolate which comprises rendering a chocolate composition fluid by heating, tempering the chocolate, shaping the chocolate composition and then lowering the temperature to a temperature below the solidification temperature of the chocolate composition, so as to produce set chocolate characterised in that cocoa powder containing a tempering amount of cocoa butter e.g. from 5 to 25 % by weight of cocoa butter based on the cocoa powder, is added when the chocolate composition is at a temperature which is the same as or just below the DSC melting point of the cocoa butter in the said cocoa powder, the cocoa powder being added in an amount such that the chocolate composition undergoes tempering, e.g. an amount of 0.05 % to 5 % by weight based on the total chocolate composition including the cocoa powder and in that preferably the cocoa powder has an average particle size in the range 10 to 15 microns.

Description

Chocolate Production

The present invention relates to the production of tempered chocolate. Chocolate can exist in a number of different morphologies known as I to VI. Chocolate in the Polymorph Form V has the desirable properties of gloss and snap which are desired for chocolate bars at the present time. Snap is the ability of the bar to break sharply rather than to bend when the bar is bent as when one snaps off a piece with ones fingers.

Chocolate bars are conventionally made by melting a chocolate composition and then pouring the molten mass into moulds allowing the mass to harden and then displacing the hardened shape e.g. a bar from the mould. The chocolate can be shaped in many other ways by analogous procedures, one widely used such procedure is to pour the molten chocolate over a body of material which has been made hard in some way so that the chocolate coats or enrobes the body to form a confectionery having a coated centre. The gloss and snap texture are also desired for such coated items. Conventionally chocolate is subjected to processing techniques known as tempering so as to bring sufficient of the chocolate into the V Form to give the desired properties. If one merely cools chocolate from a temperature such as 50°C at which it is fully molten it will solidify largely in the I or II Form which is dull and does not have snap, and is soft and bendy and is subject to bloom formation on keeping.

Chocolate confections have a very distinct taste and mouthfeel that have been enjoyed by individuals for many years. The unique flavour and mouthfeel of chocolate is a result of the combinations of its numerous components as well as its process of manufacture. Chocolate contains solids particles dispersed throughout a fat matrix which contains cocoa butter as the predominant fat in the chocolate. The term "fat" includes, for example, cocoa butter and milk fat. Accordingly, melted chocolate is a suspension of non-fat particles, e.g., sugar, milk powders and cocoa solids, in a continuous liquid fat phase. The fat phase of milk chocolate, for example, is typically a mixture of cocoa butter, a suitable emulsifier and milk fat with cocoa butter being typically the predominant fat in the chocolate.

Cocoa butter is solid at room temperature (21°C-24°C). Accordingly, chocolate is firm and solid at room temperature thereby providing good "snap" at initial bite as well as resistance to deformation and/or surface marking. Above room temperature, the fat phase melts progressively until completely melted at about 36°C.

Therefore, chocolate is typically fully melted at body temperature (about 37°C). This rapid melting in the mouth at the body temperature provides the smooth, creamy mouthfeel which results in a strong flavour impact. Cocoa butter, however, is a polymorphic material in that it has the ability to crystallise in a number of different crystal packing configurations (Wille and Lutton, "Polymorphism of Cocoa Butter". J. Am. Oil Chem. Soc, Vol. 43 (1966). Six different polymorphic forms are generally recognised for cocoa butter. Forms I and II are produced, for example, by rapidly cooling melted untempered chocolate to low temperatures and are very unstable and have a lower melting point. Forms III and IV melt at higher temperatures than Forms I and II but are not the most desirable forms for confectionery manufacture. Forms V and VI are the most stable forms of cocoa 0/02460 3

butter. It is desirable to have Form V as the predominant form in a well-tempered chocolate. Form V may transform slowly into Form VI after a period of time. Accordingly, chocolate processing is strongly linked to the crystallisation and polymorphic behaviour of the fat phase. Before chocolate can be satisfactorily processed from liquid to finished solid confection using conventional methods, it must be tempered to ensure the predominance of Form V after which is is gently cooled in order to form a set chocolate having a stable fat phase.

Before the development of tempering machines, this process was carried out by pouring the chocolate onto a marble slab and working it with a flexible spatula whilst the material cooled on the slab until it began to thicken. At this point both stable and unstable polymorphic forms were crystallised, and the thick "mush" was mixed into a bowl of warm chocolate at a temperature chosen to melt out the unstable crystals selectively prior to use. At this stage the chocolate was tempered.

The most commonly used method for currently tempering chocolate typically involves the following sequential steps:

A. complete melting of the chocolate fat phase;

B. cooling to the point of the initial crystallisation of the fat phase (i.e., below the melting point of the liquid fat phase);

C. crystallising a portion of the liquid fat phase to form stable and unstable fat crystals;

D. slight heating to melt out any unstable crystals that may have formed leaving from about 3 to 8 wt% as seeds for crystallising the remaining liquid fat; and

E. cooling to set the chocolate, typically in a cooling tunnel. Accordingly, during conventional chocolate processing, the chocolate mixture

is initially melted at temperatures of about 45°C and tempered by cooling with

agitation to about 29 to 30°C. The precise temperature-time profiles used when

tempering a chocolate will vary depending on the recipe of the formulation, the tempering equipment and even the purpose for which the chocolate will be used. The tempering of the chocolate results in a chocolate dispersion having fat crystals dispersed throughout the liquid fat phase. The chocolate suspension may then be further processed prior to solidification, for example, by enrobing the chocolate onto an edible centre or moulding the chocolate into a shape or form. The chocolate is finally set into a sufficiently solid form for wrapping by gentle, controlled cooling.

Conventional tempering therefore is the controlled partial precrystallisation of the fat phase which is believed to be necessary to produce a stable solid form of the fat in the finished product. It is an important object of tempering to develop a sufficient number of stable fat crystals so that under appropriate cooling conditions the fat phase of the chocolate is able to crystallise into a stable polymorphic form. Accordingly, the purpose of tempering is to ensure that the cocoa butter cyrstallises in a stable form.

Chocolate is derived from cocoa beans which are crushed to squeeze out cocoa butter. The bean contains about 55% cocoa butter before being crushed. The first crushing results in a fibrous mass typically having about 12% by weight cocoa butter distributed through the fibrous mass. This material is converted to cocoa powder by being ground up to a fine particle size. Some cocoa powders are made by less severe crushing and may contain up to about 22% cocoa butter. Cocoa powder can also be made in so-called defatted form which contains 0.3% cocoa butter, by solvent extraction of the fibrous mass. Cocoa powder particles are thought to carry cocoa butter on their outer surfaces.

The melting point of the cocoa butter present in cocoa powder can be measured by differential scanning techniques (DSC) the DSC peak being the melting point. When we refer to the DSC melting point this means the peak as determined when the DSC measurement is carried out at a rate of temperature rise of 10°C per minute.

The DSC melting point of the cocoa butter can vary depending on the source of the cocoa beans. Grades of West African and Indonesian cocoa powder exhibit DSC melting points of about 32°C whilst grades of Brazilian cocoa powder exhibit DSC melting points of about 30.5°C.

EP -A-0835612 teaches the addition of small amounts of fibres to fat-based confectionery which from the outset is substantially free of insoluble fibres. It teaches that by adding about 0.5 to 1.5% of defatted cocoa or 0.5 to 1.0% of natural cocoa the rate of solidification of the fat-based composition can be increased. There is no reference to chocolate compositions and no reference to tempering.

The present inventor has been trying to improve the tempering process for chocolate. He has found that the tempering process can be enhanced by adding cocoa powder to chocolate at temperatures above the solidification temperature of the original mass, shaping the chocolate and then lowering the temperature to below the said original solidification temperature. However he has found that this enhancement only occurs when the cocoa powder contains substantial amounts of cocoa butter, it does not occur when cocoa powder containing 0.3% cocoa butter is used. According to the present invention a process for tempering chocolate comprises rendering a chocolate composition fluid by heating, tempering the chocolate, shaping the chocolate composition and then lowering the temperature to a temperature below the solidification temperature of the said chocolate composition, so as to produce set chocolate, characterised in that cocoa powder containing a tempering amount of cocoa butter is added when the chocolate composition is at a temperature which is the same as or just below the DSC melting point of the cocoa butter in the said cocoa powder, the cocoa powder being added in an amount such that the chocolate composition undergoes tempering. We have found that this process enables set chocolate of good gloss and snap to be produced. This is thought to be due conversion of substantial proportions of the cocoa butter to the Polymorph V Form so that sufficient of the chocolate is in Form V to impart gloss and snap to the set chocolate.

The detection of temper is carried out by doing a temper test, the exhibition of an inflexion in the time versus temperature trace indicating that tempering has occurred. The temper test consists of taking a standard aluminium cup held at 10°C and adding a standard amount (5 grams) of the molten chocolate whose temper is to be tested and measuring the temperature of the chocolate sample with time until the temperature has fallen to about 15°C. The normal crystallisation temperature of chocolate is about 20°C. For this test, if the curve exhibits a point of inflexion at about 18°C the chocolate will be tempered and usable. If the chocolate is untempered then

there will be no point of inflexion. A point of inflexion at below 18°C indicates a low

degree of temper. The cocoa powder is preferably added to the liquid chocolate composition when the composition is at a temperature which is the same as or less than the DSC melting point (DSC peak) of the cocoa butter in the cocoa powder, e.g. 1 or 2°C lower. It is preferable to use a cocoa powder where the DSC peak is higher rather than lower because this means that the chocolate can be shaped i.e. processed when it is at a higher temperature and thus is of lower viscosity resulting in lower power requirements.

The temperature of the cocoa powder when it is added to the chocolate is less than the DSC peak of the cocoa butter in the cocoa powder, and conveniently the cocoa powder is at ambient temperature.

Once added the cocoa powder merely has to be evenly distributed into the chocolate composition. (The composition at this stage will be called the seeded composition). High shear mixing is not needed, nor is cooling of the walls of the vessel in which the mixing is occurring, in order for a good temper to be achieved; the presence of the cocoa powder of defined cocoa butter content causes the composition to acquire temper.

The seeded chocolate composition can be shaped by any of the conventional techniques or can be held at the cocoa powder addition temperature for periods of time. In contrast to conventionally tempered chocolate the seeded chocolate composition of the present invention can be held for significant periods of time e.g. 30- 60 minutes without undergoing so-called "Ostwald ripening". Ostwald ripening is a phenomenon in which small crystals of cocoa butter disappear and the larger crystals grow in size, which results in an increase in viscosity. A conventionally tempered chocolate will need to be held for a period of time before it is shaped for the temper to develop. The seeded material of the present invention will develop its temper much more rapidly and can be used immediately (as well as being able to be held at elevated temperature after tempering without "Ostwald ripening").

The shaping processes as well as moulding or enrobing in which liquid chocolate is poured or pumped or injected into moulds or over a centre which is to be coated, can include other shaping techniques such as spraying, atomization, extrusion, spin moulding, dribbling, dripping, or depositing or combinations thereof. The cocoa powder preferably contains from 5 to 25% by weight of cocoa butter based on the cocoa powder, or more preferably 7.5 to 25%. A particularly preferred range is 10 to 22%. Such cocoa powder is preferably added in an amount of 0.05 to 5% by weight based on the total chocolate composition including the cocoa powder, preferably 0.2 to 4% or 0.5 to 2% more preferably 1.0 to 1.5%. The cocoa powder preferably has an average particle size of about 10 to 50 micrometres (microns) (as measured by Coulter counter), or more preferably in the range 20 to 25 micrometres. Desirably it is screened or sieved so as to remove larger particles e.g. in excess of 125 micrometres to avoid a speckled appearance or mouthfeel effects.

Desirably the cocoa powder will show a DSC (differential scanning

calorimetry) peak of around 32°C or above e.g. 32 to 36°C.

Cocoa powders which have proved effective are West African high fat (20-22% cocoa butter), West African (10-12% cocoa butter) and Indonesian (10-12% cocoa butter). We have found that the procedure of the present invention permits chocolate processing to be carried out at increased temperatures e.g. 31-32°C rather than 29-30°C which gives power and throughput benefits whilst still enabling excellent temper of the chocolate to be achieved. The invention may be put into practice in various ways and a number of specific embodiments will be described to illustrate the invention with reference to the accompanying drawings in which:

Figure 1 is a time/temperature trace for the temper test on the chocolate of example 4, Figure 2 is a time/temperature trace for the temper test on the chocolate of example 5,

Figure 3 is a time/temperature trace for the temper test on the chocolate of example 6,

Figure 4 is a time/temperature trace for the temper test on the chocolate of example 7,

Figure 5 is a time/temperature trace for the temper test on the chocolate of example 8,

Figure 6 is a DSC trace for the West African high fat cocoa powder used in Example 1A, Figure 7 is a DSC trace for the West African 10-12% fat cocoa powder used in

Examples 2 A, 2B, 7 and 8,

Figure 8 is a DSC trace for the Indonesian 10-12% fat cocoa powder used in Examples 3 A, 3B, 5 and 6 and Figure 9 superimposes the traces of Figures 6, 7 and 8 on the same scale, curve 13 being Figure 6, curve 14 being Figure 7 and curve 15 being Figure 8.

The DSC traces are carried out using standard techniques and procedures the temperature being raised from 10°C to 60°C at a rate of 10°C per minute, temperature being plotted against heat flow.

Examples 1A and IB

Cocoa powder consists of cocoa fibre (largely cell wall material with interstitial and surface deposits of cocoa butter. A sample of a West African high fat (20-22%)

cocoa powder was obtained. The DSC peak of this cocoa powder was 32.6°C.

Samples of molten chocolate (made up from the ingredients given in Table 1

below) at 32°C had 0.5 (Ex 1 A) and 1.0% (Ex IB) of the cocoa powder (at ambient temperature) vigorously stirred in by hand in an uncooled bowl, the walls of which were at ambient temperature (20-25°C). The chocolate after mixing had a temperature of 32°C. When temper tested, as described above, both examples showed an inflexion and a distinctive positive slope. Small test moulds made from the chocolate showed small dark specks. These were eliminated by pre-sieving the cocoa powder

through a 125μ mesh sieve.

Table 1 Ingredient Parts by weight

Sugar 47.76

Milk powder 22.74

Cocoa butter 15.2 Chocolate liquor 8.38

Vegetable fat 4.99

Lecithin 0.65

Vanillin 0.0027 Water 0.25

Examples 2A and 2B

A sample of West African cocoa powder (10-12% fat) (Ex 2A 0.5%) (Ex 2B 1.0%) was used in the same way as in Example 1 A and IB with very similar results.

This chocolate was kept at 31.5-32°C for 2.5 hours and regular temper checks showed minimal change in the temper level. The DSC peak of this cocoa powder was 32.2°C. Example 3 A and 3B

When Examples 2A and 2B were repeated with 0.5% (Ex 3 A) and 1.0% (Ex 3B) of Indonesian cocoa powder containing 10-12% cocoa butter similar results were

obtained. The DSC peak of this cocoa powder was 32°C. Example 4

5.0 kg of chocolate (made up from the ingredients given in Table 2 below) at

about 45 °C was weighed into a Hobart planetary mixer, the bowl of which was not

cooled and was at ambient temperature (22-23°C) and the mass of chocolate was

allowed to cool gradually over about 1 hour to 32°C. A small amount was removed,

tempered on a cool plate (10°C) and returned to the bulk of the chocolate. This was repeated until an obvious low temper was obtained (see curve 1 in Fig 1). Curve 1 in

Figure 1 shows a point of inflexion at 16.7°C. The temperature of the chocolate mass

had by now dropped to 30°C. 20 trays of 14 gram bars were prepared by weighing the exact amount into the mould. This was spread and vibrated. During the course of this procedure no additional tempering of the bulk occurred.

This example is a comparison example and shows a conventional tempering process.

Table 2

Ingredient Parts bv weight

Sugar 45.7

Milk powder 24.1

Cocoa butter 15.1

Chocolate liquor 8.95

Vegetable fat 4.98

Lecithin 0.88

Vanillin 0.0027

Water 0.24

Examples 5 to 8

Each example was made from 2.5kg of the same chocolate as in Example 4 added at a chocolate temperature of about 45°C to the uncooled bowl of the Hobart mixer which was at ambient temperature (22-23°C). After the addition the chocolate temperature was about 44°C. The mass of chocolate was allowed to cool over about

1 hour to 31 °C and a temper test carried out to confirm that there was no temper

development. The required amount of cocoa powder (at ambient temperature) as seeding agent (see Table 3) was added and folded or stirred in using the Hobart planetary mixer blade at speed 1 (at which speed the planetary rotation is at 60 rpm, whilst the impeller rotates at 140 rpm) for about 1 minute to give even distribution of the cocoa powder but without subjecting the chocolate to any significant cooling or shear.

A temper test was immediately carried out and 10 trays were moulded using the above method. When all moulding was completed further temper tests were carried out. The results of all these temper tests are given in Figures 2 to 5. In Figure 2 (Ex 5) curve 2 shows no point of inflexion, curve 3 shows a point of inflexion of

18.3°C and curve 4 shows a point of inflexion of 17.9°C.

Curve 2 is of the basic chocolate composition at the cocoa powder addition temperature to which cocoa powder had not yet been added.

Curve 3 is of the mixture 1 minute after the cocoa powder had been added and stirred in.

Curve 4 is of the mixture 15 minutes after the cocoa powder had been added in.

In Figure 3 (Example 6) curve 5 shows no point of inflexion, curve 6 shows a

point of inflexion of 18.5°C and curve 7 shows a point of inflexion of 18.3°C.

Curve 5 is of the basic chocolate composition at the cocoa powder addition temperature to which coco a powder had not yet been added.

Curve 6 is of the mixture 1 minute after the cocoa powder had been added and stirred in.

Curve 7 is of the mixture 15 minutes after the cocoa powder had been added in.

In Figure 4 (Example 7) curve 8 shows no inflexion and curve 9 shows a point

of inflexion at 19.4°C. Curve 8 is of the basic chocolate composition at the cocoa powder addition temperature to which cocoa powder had not yet been added and stirred in.

Curve 9 is of the mixture 1 minute after the cocoa powder had been added and stirred in. In Figure 5 (Example 8) curve 10 shows no inflexion, curve 11 shows a point

of inflexion at 20.3°C and curve 12 shows a point of inflexion at 20.1°C.

Curve 10 is of the basic chocolate composition at the cocoa powder addition temperature to which cocoa powder had not yet been added and stirred in.

Curve 11 is of the mixture 1 minute after the cocoa powder had been added and stirred in.

Curve 12 is of the mixture 15 minutes after the cocoa powder had been added and stirred in.

Comparison of curve 3 with curve 4 and of curve 6 with curve 7 and of curve 11 with curve 12 indicate that the temper develops rapidly and does not change much after 15 minutes at the cocoa powder addition temperature.

The graphs of the chocolates of Examples 5 to 8 all show a suitable level of temper for either moulding or enrobing. The inflexion points given in Table 3 indicate that tempering occurred but that the different sources of cocoa powder may have different tempering abilities. Table 3

All the samples demoulded easily.

The chocolate of Example 4 and the chocolate of Example 7 each had their

viscosities measured at 29°C, 30°C and 31°C, using the same measurement technique.

At each temperature the viscosity of the chocolate of Example 7 was less than that of Example 4. Thus the addition of the cocoa powder produced a useful lowering of the viscosity of the chocolate as well as enhancing the tempering.

Claims

1. A process for tempering chocolate which comprises rendering a chocolate composition fluid by heating, tempering the chocolate, shaping the chocolate composition and then lowering the temperature to a temperature below the solidification temperature of the chocolate composition, so as to produce set chocolate characterised in that cocoa powder containing a tempering amount of cocoa butter is added when the chocolate composition is at a temperature which is the same as or just below the DSC melting point of the cocoa butter in the said cocoa powder, the cocoa powder being added in an amount such that the chocolate composition undergoes tempering.

2. A process as claimed in claim 1 characterised in that cocoa powder contains from 5 to 25% by weight of cocoa butter based on the cocoa powder, or more preferably 7.5 to 25%, a particularly preferred range being 10 to 22%.

3. A process as claimed in claim 1 or claim 2 characterised in that the cocoa powder is added in an amount of 0.05 to 5% by weight based on the total chocolate composition including the cocoa powder, preferably 0.2 to 4% or 0.5 to 2% more preferably 1.0 to 1.5%.

4. A process as claimed in claim 1, 2, or 3 characterised in that the cocoa powder has an average particle size in the range 10 to 50 microns.

5. A process as claimed in claim 1, 2, 3 or 4 characterised in that the cocoa powder has an average particle size of about 20 to 25 micrometers (microns).

6. A process as claimed in any one of claims 1 to 5 characterised in that the temperature of the chocolate composition when the cocoa powder is added is 0 - 2┬░C, or 0.5 - 2┬░C or 0.5 - 1.5┬░C lower than the DSC peak of the cocoa butter in the cocoa powder.

7. A process as claimed in any one of claims 1 to 6 characterised in that the DSC peak of the cocoa butter in the cocoa powder is 32┬░C or higher.

8. A process for producing a shaped chocolate product characterised in that it comprises rendering a chocolate composition fluid by heating, tempering the chocolate, shaping the chocolate composition and then lowering the temperature to a temperature below the solidification temperature of the chocolate composition, so as to produce set chocolate characterised in that cocoa powder containing a tempering amount of cocoa butter is added when the chocolate composition is at a temperature (the cocoa powder addition temperature) which is the same as or just below the DSC melting point of the cocoa butter in the said cocoa powder, the cocoa powder being added in an amount such that the chocolate composition undergoes tempering and in that the tempered chocolate composition is held at a temperature between the shaping temperature and the cocoa powder addition temperature for 30 ΓÇö 60 minutes without undergoing significant Ostwald ripening.

9. A process as claimed in claim 8 characterised in that cocoa powder contains from 5 to 25% by weight of cocoa butter based on the cocoa powder, or more preferably 7.5 to 25%, a particularly preferred range being 10 to 22%.

10. A process as claimed in claim 8 or claim 9 characterised in that the cocoa powder is added in an amount of 0.05 to 5% by weight based on the total chocolate composition including the cocoa powder, preferably 0.2 to 4% or 0.5 to 2% more preferably 1.0 to 1.5%.

11 A process as claimed in claim 8,9 or 10 characterised in that the cocoa powder has an average particle size in the range 10 to 50 microns.

12. A process as claimed in claim 8,9,10 or 11 characterised in that the cocoa powder has an average particle size of about 20 to 25 micrometers (microns).

13. A process as claimed in any one of claims 8 to 12 characterised in that the temperature of the chocolate composition when the cocoa powder is added is 0 - 2┬░C, or 0.5 - 2┬░C or 0.5 - 1.5┬░C lower than the DSC peak of the cocoa butter in the cocoa powder.

14. A process as claimed in any one of claims 8 to 13 characterised in that the DSC peak of the cocoa butter in the cocoa powder is 32┬░C or higher.

15. A chocolate product whenever made by a process as claimed in any one of claims 8 to 14.