This invention relates to an aerated chocolate composition and preparation thereof, in particular a stable chocolate foam composition and preparation thereof.

Background of the invention

The pleasant flavour and superior texture are the two major characteristics of chocolate. Chocolate must be solid in room temperature, and yet melt rapidly in the mouth at 37 oC to give the smooth mouth feeling. Dark chocolate, milk chocolate and white chocolate are the three major flavours.

Chocolate is often used as a coating in the food industry. The inventors have investigated means for reducing the calorific value of the chocolate but without reducing the sensory experience provided by the chocolate coating.

Aerated or foamed chocolate are well known products on the market. Examples are Nestle aero, and Mars Skye bar. The main methods for the manufacturing of aerated chocolate are that (1 ) gas is mixed thereinto by dissolving or under high pressure followed by solidification of the chocolate and then the quickly released gas cells can be locked in the solid chocolate matrix ; (2) The molten chocolate is continuously stirred to foam followed by cooling, so called whipped chocolate (EP 1 166 639 A1 ).

In the first method, the gases such as air or carbon dioxide, can be dissolved in molten chocolate under high pressure with or without the help of stirring. After de- pressurisation, the dissolved gas will come out to form gas cells in the chocolate, and these gas cells will be locked in the chocolate matrix if the temperature is quickly cooled down below the melting temperature of chocolate during the de- pressurisation process. The solidified chocolate will keep the gas cells and stabilised the prepared chocolate foam. However, the gas cells are normally big and the aeration is not easy to control. If the chocolate is above its melting temperature, the chocolate foam is not stable and thus the coating, dipping and rolling which are common for chocolate application, can not be applied to the chocolate foam prepared by this method.

In the second method, molten chocolate is stirred to foam and normally extra emulsifiers and shortenings will be required.

It has now been found that it is possible to aerate chocolate under certain conditions by carefully selecting emulsifiers and aeration conditions. Moreover, the aeration characteristics remain largely untouched if the chocolate is later melted and re-solidified.

GB1297579 discloses a foamed chocolate containing a polyglycerol ester and an optional secondary emulsifier, which can be Span 20. When reproducing examples 9 and 1 1 in this document, very poor overrun was obtained.

It has now been found that certain sorbitan esters can aerate chocolate at temperature above 40 ^° C. The resulting aerated chocolate can stay stable at temperatures where the chocolate is molten. The prepared chocolate foams have naked-eye invisible bubbles, which can add extra benefits to the texture, mouth- feeling, calorific reduction et al. They also should exceptionally good stability upon melting and re-solidifying

Tests and definitions

Sorbitan esters

Chocolate

By the term "chocolate" is meant dark chocolate, milk chocolate, white chocolate, flavoured chocolate, couverture chocolate, compound chocolate (which is made from a combination of cocoa solids, non-cocoa butter vegetable fat and sweeteners) and mixtures thereof. The chocolate may also comprise inclusions such as nuts or pieces thereof, dried fruit, such as raisins, or pieces thereof, biscuit and mixtures thereof. The chocolate must, however, remain substantially anhydrous. By the term "substantially anhydrous" is meant comprising no more than 5%, preferably no more than 3%, more preferably no more than 1 % w/w water.

HLB value

The HLB value is given by the equation HLB = 20 ^* M _h /M, where M _h is the molecular mass of the hydrophilic part of the molecule and M is the molecular mass of the whole molecule thus giving a value on an arbitrary scale of 0 to 20. For fatty acid esters, HLB = 20 (1 -S/A) where

S = Saponification value

A = Acid number of the fatty acid

Therefore an HLB value of 0 corresponds to a completely hydrophobic molecule and an HLB value of 20 corresponds to a completely hydrophilic molecule.

Typical HLB values are:

0 to 3 an anti-foam ing agent

4 to 6 a water-in-oil emulsifier

7 to 9 a wetting agent

8 to 18 an oil-in-water emulsifier

13 to 15 a detergent

10 to 18 a solubiliser or a hydrotrope

Overrun

"Overrun" is a measure of aeration commonly used in the ice cream industry and is defined in percentage terms as follows: Overrun = (Weight difference before and after aeration / weight after aeration) *100 wherein the sample weight both before and after aeration is for the same given fixed volume.

Stability of aerated chocolate

The stability of aerated chocolate at warm temperature was studied by maintaining the aerated chocolate samples at 45 degrees centigrade and the weight in a fixed volume was measured at determined time points to get the change in their overruns with time. Microscopy images were also taken to compare the morphology change of gas bubbles in the aerated chocolate.

General manufacturing conditions

Aeration of chocolate

The aeration was carried out using a Kenwood KMX50 Mixer at different speed (lowest speedl to highest speed7) for certain time (5 mins to 20 mins) at a temperature of 40 to 75 degrees Celsius). The aerated mixtures were kept at warm temperature (40-60 ^° C) or cooled down to room temperature. Summary of the Invention

In a first aspect of the invention, an aerated chocolate composition is provided, the aerated chocolate composition having an overrun of between 20% and 100%, preferably above 30%, preferably also below 70%, containing 1 -10%, more preferably 1 -5% w/w, of at least one sorbitan ester having a melting temperature of above 15 ^° C, preferably above 25 ^° C, more preferably above 35 ^° C.

Preferably the chocolate composition is substantially anhydrous.

Preferably, the overrun of the aerated chocolate composition is stable. It means that the overrun of the composition does not decrease by more than 20%, preferably 10%, most preferably 5% over a period of 24 hours when the composition is kept at a temperature of at least 40 ^° C.

Thus a chocolate composition has now been provided which, on a volume basis, has a lower calorific value than an un-aerated chocolate composition as a proportion of the volume of the aerated chocolate composition comprises a gas.

A further advantage of such a chocolate composition is the different sensorial effect that such a composition has over an un-aerated chocolate composition which could be due to the presence of gas bubbles which burst on the tongue on consumption of the composition.

A particular advantage of the stable chocolate foam composition is that the gas bubbles are not visible to the human eye and thus do not detract from the visible appearance of the chocolate composition. This is particularly important when the composition is used to provide a coating.

Another important advantage is that the overrun is maintained on re-melting. This is important as chocolate compositions are often supplied in a solid form and re- melted just prior to use. This advantage obviates the need for the user to aerate the chocolate composition just prior to use saving on equipment costs and time. Typically, the overrun loss during re-melting is less than 10%.

In a 2nd aspect of the invention, a process for manufacturing the stable chocolate aerated composition is provided, the process comprising the steps of:

(a) Providing the chocolate composition of the first aspect of the invention, wherein the chocolate composition containing the at least one sorbitan ester is melted at a temperature of between the melting temperature of the at least one sorbitan ester and 30 degrees Celsius, preferably 20 degrees Celsius, more preferably 15 degrees Celsius, most preferably 10 degrees

Celsius above the melting temperature of the at least one sorbitan ester; then Mechanically aerating the chocolate composition at least at a temperature of 40 degrees Celsius and between a temperature of 40 degrees Celsius and 30 degrees Celsius, preferably 20 degrees Celsius, more preferably 15 degrees Celsius, most preferably 10 degrees Celsius above the melting temperature of the at least one sorbitan ester to a desired overrun thereby to produce a an aerated chocolate composition; and then

Optionally cooling the aerated chocolate composition.

The term "mechanically aerated" excludes aerating means using propellant, such as nitrous oxide. Preferably the chocolate composition is mechanically aerated using a high speed stirrer, a high speed whisk or a homogeniser. In an alternative preferred embodiment of the invention, the aeration is done by gas dissolution under pressure. Detailed Description of the Invention

Examples 1 & 2

500g of each example were prepared and aerated as described hereinabove at the temperatures indicated in table 2 using sorbitan palmitate (Span 40 (melting temperature 45 degrees centigrade; and HLB=6.7)) and sorbitan stearate (Span 60 (melting temperature 54 degrees centigrade; and HLB=4.7)), both available from Croda Europe Limited. The aerated mixtures were cooled down to room temperature and their overruns measured at room temperature before and after re-melting. The results are summarised in table 2.

The results show that chocolate foam compositions may be obtained with satisfactory overruns using a variety of emulsifiers with HLB values ranging from 4 to 7. Furthermore the overrun on remelting is the same as before remelting so the overrun is very stable on remelting. Table 2: Overrun (%) and remelting overrun (%) of examples comprising a variety of emulsifiers in dark chocolate (emulsifier concentration given as % commercial emulsifier as delivered).

Examples 3 to 7

Additional examples comprising 5% by weight Span 60 (sorbitan stearate) were prepared as described hereinabove but at temperatures of 40 ,50, 55, 60 and 65 degrees centigrade. The aerated mixtures were cooled down to room temperature and their overruns measured. The results are summarised in table 3 and show that aeration is a function of temperature.

Table 3: Examples comprising 5% by weight Span 60 (sorbitan stearate) prepared at different temperatures.

Comparative examples

Two chocolate with 1 % Span 20 and 0.5% PGE (first example) and 1 % Span 20 and 1 % PGE (second example) were produced as in GB1297579, overruns of less than 5% were obtained. Also chocolate compositions with Span 80 and Span 85 were produced, again, it was not possible to aerate the compositions to any significant level.