WO2008025803A1

WO2008025803A1 - Reduced calorie cocoa butter composition and preparation and use thereof

Info

Publication number: WO2008025803A1
Application number: PCT/EP2007/059002
Authority: WO
Inventors: Christian Manuel Vastenavond
Original assignee: Nv Nutrilab SA
Current assignee: Nv Nutrilab SA
Priority date: 2006-08-30
Filing date: 2007-08-29
Publication date: 2008-03-06
Anticipated expiration: 2009-02-28
Also published as: EP2056679A1

Abstract

The invention pertains to a reduced calorie cocoa butter composition, being a w/o emulsion containing an aqueous dispersion of solidified droplets containing a hydrophilic colloidal stabilizer in a continuous phase containing cocoa butter. The invention further pertains to a process for making the same, by (i) providing cocoa butter at a temperature above its softening point, (ii) adding thereto, using encapsulation, an aqueous composition containing a hydrophilic colloidal stabilizer at a temperature of at least the softening temperature of the cocoa butter or the gelling temperature of the hydrophilic colloidal stabilizer, whichever is higher, to obtain a w/o emulsion in which the continuous phase contains cocoa butter, and (iii) solidifying the dispersed aqueous phase therein. Even more preferably, the process comprises the further steps of (iv) cooling the emulsion to a temperature below 10 °C for a period of at least 1 day; (v) melting the cooled emulsion; and (vi) subjecting the melted emulsion to agitation.

Description

Reduced calorie cocoa butter composition and preparation and use thereof

TECHNICAL FIELD OF THE INVENTION

The invention pertains to a reduced calorie cocoa butter composition, to the preparation thereof, and to the use thereof in chocolate manufacture.

BACKGROUND OF THE INVENTION

Consumer awareness of the caloric content of food has increased very much over the past few years and has brought about a demand for foods having a reduced fat content. This demand has created a need in the food industry to replace at least a portion of the fat and/or oil in prepared foodstuffs. Since then, a lot of products have been commercialized in which the fats have been replaced at least partially by other low- caloric compounds such as proteins, gelatins, hydrolyzed or modified starches, malto- dextrins etc. as disclosed in EP-A-237.120 ,WO-A-93/17565 and WO-A-96/03057. The desire for fat replacers in foods has also reached the chocolate manufacture industry, where the high caloric value of cocoa butter is of great concern. For instance, US 4,822,875 describes certain sucrose fatty acid esters, and US 5,387,429 discloses esterifϊed propoxylated glycerin compositions, both reportedly useful cocoa butter substitutes, closely mimicking the desirable melting properties of cocoa butter: cocoa butter is solid at about 18°C and fully liquid at 36°C.

However, despite these kind of attempts up until now it has proven to be extremely difficult to replace high caloric cocoa butter in chocolate, without deteriorating the otherwise excellent non-waxy mouthfeel and consistency cocoa butter provides to the chocolate product. The uniqueness of cocoa butter is attributable to the particular combination and positional distribution of fatty acid acyl groups on the three carbons of glycerol. Cocoa butter contains approximately equimolar proportions of three major fatty acid acyl groups (palmitate, stearate, oleate). Simple replacement of (part of) the cocoa butter by adding in these fat replacers does not compensate for these special cocoa-related features, especially not in terms of its retraction and crystallization properties.

US 2005/0118311 is directed to the manufacture of reduced- fat, flavored coatings to mimic the melting of cocoa butter during consumption. The coating has less than about 10 wt% fat which exists as dispersed micro-droplets. These are obtained by spray-drying. Water plays no role in the finished product.

It is also known from the prior art to increase the melting point of chocolate by dispersing gelled water droplets to the chocolate. These dispersions are obtained by mere mixing of the ingredients, without any means to control particle size. Such mixing- as demonstrated in the accompanying comparative examples - results in relatively large droplets. This is also clear from the prior art itself: US-A-2005/0118327 teaches 20 - 80 μm droplets on average, EP-A-688.506 reports sizes of the order of even hundreds of μm (see tables II and II therein); and mixing in US 5,425,957 is continued until the globule size of the emulsion ranges between 20 and 60 μm. Although US 6,010,735 is silent on the actual droplet size achieved by "full speed mixing" (see examples therein), it is obvious that the resulting droplets are similarly large.

Although these documents may provide the solution desired in the prior art to "tropicalize" chocolate, they are silent on the problem of providing low-calorie chocolate without affecting its appearance and taste perception, and the effect of particle size therein. Moreover, coalescence is often reported for these cases.

Outside the field of chocolate, where the special properties of cocoa butter remain unrecognized, GB-A-2,035,360 teaches a process of preparing fat-continuous emulsions using mixing and spraying, to obtain a droplet size of 4 - 20 μm for at least 80 % of the droplets. However, it is mentioned that droplets of 8 or more microns easily release in the mouth and are thus preferred.

In addition, US-A-2006/128815 teaches a membrane emulsification method for preparing mixtures of immiscible fluids, such as oil and water, whereby each can serve as the dispersed or continuous fluid. However, it is preferred that the continuous phase is water, and it may be applied in food products such as sauces, fresh cheese, mayonnaise, spreadable products and dressings. Membrane emulsification is based on the use of a microporous membrane to prepare monodisperse emulsions with droplets of pre-determined size. However, membrane emulsification and other encapsulation techniques may have been associated with food applications, mostly for preserving stability, but never in relation to reducing the caloric content of foods, let alone in chocolate manufacture. Hence, there is a need in the art for low caloric chocolate food product having a visual appearance and taste perception, especially in terms of melting behaviour, non- waxy mouthfeel and consistency, indifferent from its traditional calorie-rich counterpart. For that purpose, there is a demand for partial cocoa butter replacement which could realise these effects, thus resulting in a low calorie cocoa butter-containing chocolate food product.

DESCRIPTION OF THE INVENTION

It is an object of the invention to provide a low-caloric cocoa butter composition suitable for replacing at least part of the cocoa butter normally present in chocolate, without affecting the organoleptic properties of the chocolate confectionary in view of its calorie-rich counterpart. Therein, it is not considered sufficient to mimic cocoa butter melting behaviour; the replacement composition should also exhibit the capacity to retract during solidification and crystallisation as to allow suitable demoulding in the actual chocolate manufacture.

It is now found that this object can be achieved by encapsulating an aqueous dispersion in a continuum of cocoa butter, wherein the dispersed phase is so lid- like, for instance achieved by gelling.

The invention thus pertains to a reduced calorie cocoa butter composition being a w/o emulsion containing an aqueous dispersion of solidified droplets in a continuous phase containing cocoa butter. Droplet size and droplet size distribution play an important role therein.

It is preferred to incorporate an emulsifier, such as polyglycerol polyricinileate (PGPR), which forms a membrane, encapsulating the gelled water particle. The invention is not particularly limited to a source of cocoa butter. "Cocoa butter" in the context of the invention also comprises cocoa butter substituents known in the art. However, in a preferred embodiment the continuous phase contains at least 75 vol%, in particular at least 90 vol% of cocoa butter. In addition to the aforementioned physical characteristics, the softening temperature of the cocoa butter is between 30 - 32 °C, dependent on the actual source. In the context of the invention, the terms "fat" and "oil" are used interchangeably. It is preferred that the water droplets further contain fat-mimicking carbohydrates. It is believed that the water-soluble carbohydrate fat mimics interact with the water to replace some of the functionality of the cocoa butter. The water provides the smooth body and mouthfeel of the fat. However, since water decreases shelf life and reduces emulsion stability, hydrophilic colloidal stabiliser gels are to be applied to solidify the aqueous phase. Hence, in the context of the invention with "solidified" is also understood "gelled" or otherwise physically immobilized. The incorporated water may still be available for microbes to grow and chemical reactions to take place, but the effect is localized, thus minimizing the effect on the chocolate confectionary using the reduced calorie cocoa butter composition of the invention. Further, gelling prevents the water from reacting with starches present in the cocoa butter preparation, which would otherwise result in perceptable (and thus undesirable) hard "stone-like" pieces in the chocolate, and which would hinder conching, the long process of intense mixing, agitating and aerating of heated liquid chocolate.

To achieve solidification, gelable hydrophilic colloidal stabilizers may be used. The stabilizer may be any of those already described in the art, preferably selected from the group consisting of microcrystalline cellulose, carrageenan, guar gum, alginate, xanthan gum, methyl cellulose, carboxylmethyl cellulose, ethyl cellulose, dextrin, starches, gelatine, locust bean gum, soy protein isolate, pectin and the like. Roughly speaking, the stabilisers are ungelled at a temperature above 95°C, but solid-like at normal storage conditions.

Pectin has been found to be particularly effective. Pectin may be used as obtained from citrus peel, apple pomace, or other appropriate edible plant material. It is a carbohydrate product consisting mainly of galacturonic acid and galacturonic acid methyl ester units forming linear polysaccharide chains. In the art, pectins are roughly divided into three groups on the basis of their different gelling properties, distinguishing between high methoxy (HM), low methoxy (LM) and amidated pectins, either HM or LM. HM pectins require a minimum amount of soluble solids (about 55%) and a low pH for gelation. They have a degree of esterifϊcation greater than 50%, and form thermally irreversible gels in the presence of sugars at pH less than 3.5. LM pectins have a degree of esterifϊcation less than 50%, and their gelling properties are not dependent on pH; thermally reversible gels are induced by calcium ions and function, and pH is less restrictive therein. Amidated pectins are pectins which have been de- esterified with ammonia instead of acids. During de-esterifϊcation, part of the ester groups has been replaced by amide groups, which modifies the gelling properties in comparison to acid de-esterified pectins.

There are many commercial pectins available that provide the required gelling behavior, such as Slendid, commercially available from CP Kelco, and Unipectine (LSF series) from Degussa (Dϋsseldorf, Germany). The most preferred pectin in the context of the invention is a LM amidated pectin, since it is more pH tolerant and allows for favourably thermo-reversible gel formation. The pectin typically gels at a temperature lower than about 55 °C.

The amount of pectin is selected such that it can establish gelling of the aqueous phase. In practice 0.5 - 2O g per kg water may be used. It is preferred that 0.1 - 5 % pectin is present in the emulsion.

Optionally, fat replacers other than water and stabilizer are applied. It is found particularly useful to use fat-mimicking carbohydrates, especially fibers. Where fibers are used, microbial growth is inhibited. With "fat-mimicking" carbohydrates it is meant the fat-replacing carbohydrates existing in the art. These are preferably water-soluble. Non-limiting examples are cellulose, dextrins, fibers, gums (e.g. guar gum, Arabic gum, locust beam gum, xanthan gum, carrageenan), inulin, maltodextrin, oatrim, poly dextrose, polyols, and starch or modified starch. Combinations may also be applied. The amount of fat-mimicking carbohydrates other than pectin is preferably between 1 - 50O g per kg water. The fat-mimicking carbohydrates preferably contain some kind of a randomly bonded polymer of glucose, especially those recognized as fibers in the art. Short chain amylose in US 5,711,986 is an example thereof. High molecular weight polysaccharides supply the slippery mouthfeel of fat, while low molecular weight oligosaccharides are known to contribute to the sugar functionality. Polydextrose is the preferred choice as described in the Foods Chemicals Codex (FCC) Monograph as a randomly bonded (1,6-glycosidic linkage predominates) condensation polymer of D- glucose, sorbitol, and citric acid. The commercial product also contains small amounts of free glucose, sorbitol, citric acid, and 1 ,6-anhydro-D-glucose (levoglucosan). Polydextrose may be applied having a molecular weight ranging from 162 to 20,000, preferably having 90 % having a MW between 504 and 5,000. Preferably, the average degree of polymerization is 12, corresponding to an average molecular weight of approximately 2000. It is only partially metabolizable, providing 1 kcal/g.

Another preferred fat-mimicking carbohydrate is inulin, which is a natural, soluble dietary fiber extracted from e.g. chicory roots and is composed of linear chains of fructose molecules varying in length from 2-60 units. These chains are connected by beta(2-l) linkages and are often terminated by a glucose unit. Because of different levels of free sugars, inulin products have a variety of caloric contents, ranging from 1 to 1.5 kcal/g.

It is especially favourable to inulin and/or polydextrose as fat-mimicking carbohydrates, in particular both. It is observed that droplets are formed having a core dense in the above-mentioned fibers, captured by a shell layer rich in gelled pectin. If emulsifϊers are used, these mostly contribute by forming a second shell layer on the outside of the droplet, thus controlling the distance among the droplets.

Salt, preferably CaCl₂, may be added to the aqueous phase to further stabilize. In order to obtain a stabilized w/o emulsion of an aqueous phase encapsulated in a continuous phase containing cocoa butter showing significant caloric reduction, it is found that the preferred volume ratio of the continuous phase (containing cocoa butter) to the aqueous dispersed phase is between 3:1 and 1 :2, more preferably in the range of 2:1 to 1 :1. Hence, a 50 % energy reduction may easily be obtained this way.

Best results are obtained if that the emulsion exhibits a substantially uniform droplet size distribution throughout. The dispersed droplet size and its distribution affect many of the physicochemical properties of the emulsion. For once, the size of the droplets is a determining factor for the stability of the emulsion. In addition, droplet size may affect the flavour of the product and also has great effect on growth of bacteria. If the dispersed droplet diameter is large, bacteria multiply readily; if the dispersed droplet diameter is small, bacterial growth may be suppressed due to lack of nutrients in the interior of droplets.

It is found that optimal results are obtained if the average droplet size is between 0.05 and 15 μm, preferably in the range of 0.1 - 10 μm, more preferably 1 - 6 μm. A "substantially uniform distribution" is preferably understood to comprise a distribution of droplets of which the largest and the smallest diameters are no more than 5 μm, more preferably no more than 3 μm remote from the average size. Most preferably, the w/o emulsion of the present invention is a monodisperse emulsion wherein at least 95 vo 1%, preferably at least 96 vol% dispersed droplets have a size within a range of 0.05 - 15 μm, most preferably 0.1 - 10 μm, more preferably 0.5 - 6 μm, in particular 1 - 5 μm. To optimize microbial growth prevention, it is preferred that at least 95 vol% of the droplets has a size between 0.1 - 5 μm, in particular 0.5 - 3 μm.

In the most preferred embodiment, at least 95 vol%, more preferably at least 98 vo 1% of the droplets has a size between 0.05 and 1 μm, more preferably 0.1 - 0.5 μm, and the largest droplet size is preferably less than 10 μm , more preferably less than 5 μm, in particular less than 3 μm. Advantageously, these domains are too small for bacterial growth.

Optionally art-known additives, such as emulsifϊers, flavours, vitamins and colorants may be present in either phase. A particularly suitable emulsifϊer is a biodegradable hydrophobic emulsifϊer, such as polyglycerol polyricinoleate as disclosed in EP-A-559.013, EP-A-44.203 and WO-A-85/04346, which will be present in the continuous phase.

The energy content of the cocoa butter composition may be further reduced by replacing a part of the cocoa butter in the continuous phase, with partial fat replacers known in the art. It is preferred that the continuous phase contains up to 25 %, more preferably up to 10 vol% of fat replacers. For instance, a partial fat replacer, such as mixtures of palm mid fraction and l,3-distearyl-2-oleyl glycerol (SOS) and/or 1- palmityl-2-oleyl-3-stearoyl glycerol (POS) as described in US 4,283,436 may be added to the continuous phase. Palm mid fraction is the product prepared by acetone fractionation as described and characterized in GB 827,172.

The invention further pertains to a process for preparing the above-described low- caloric cocoa butter composition by (i) providing cocoa butter at a temperature above its softening point, (ii) emulsifying , an aqueous composition containing a hydrophilic colloidal stabilizer into said cocoa butter, at a temperature of at least the softening temperature of the cocoa butter or the gelling temperature of the hydrophilic colloidal stabilizer, whichever is higher, to obtain a w/o emulsion in which the continuous phase contains cocoa butter, and (iii) solidifying the dispersed aqueous phase therein.

As already addressed in the background section, conventional emulsifϊcation methods rely on stirring utilizing high shear, in which case coalescence of the dispersed phase may occur. Traditional stirring equipment, colloid mills, homogenizers, ultrasonics and microfluidizers do not achieve the aforementioned essential droplet size and size distribution, and often do not result in emulsion stability over normal processing times. Hence, shear- induced emulsifϊcation alone is not part of the invention.

The emulsification of the aqueous phase into the cocoa butter should involve some kind of (micro)encapsulation technique, either mechanically (e.g. spray drying) or chemically (simple or complex coacervation). A. Madene et al. "Flavour encapsulation and controlled release - a review" Int. J. Food Sci. & Technology (2006) 41, 1 -21) provides an overview of the different available microencapsulation techniques which may be applied in food industry, mostly for preserving stability. Essentially, encapsulation is a widely used barrier technology, preventing ingredients from reacting prematurely with their environment or from degrading during processing or storage. It is found that best results in terms of homogeneity are achieved if the stabilizer is completely dissolved in the aqueous composition prior to mixing. This is especially the case if pectin is applied as the hydrophilic colloidal stabilizer. It is preferred to first dissolve the stabiliser in water, and only upon complete dissolution add other solutes. It is preferred to apply high shear mixing to establish complete dissolution of the stabiliser and other components. The aqueous composition and the cocoa butter are mixed together at a volume ratio of preferably 3:1 and 1 :2, more preferably in the range of 2:1 to 1 :1.

The pH of the aqueous composition is preferably maintained at 5 - 6, more preferably 5 - 5.7 to provide effective microbial control and good flavour with the lowest necessary levels of preservatives in the ultimate product. It is preferred to add antimicrobials such as sodium sorbate, potassium sorbate and/or phosphoric acid to the aqueous composition. Propylgallate may be added as antioxidant to prevent fat mimic oxidative deterioration. Of all available encapsulation methods, membrane emulsification such as taught in US- A-2006/128815 or GB-A-2,385,008 is found particularly suitable, since it enables the formation of monodisperse emulsions with droplets of pre-determined size. Modifications will readily occur to those skilled in the art. Using membrane emulsification, the aqueous phase is emulsified under pressure, typically from 1 to 10 bar, preferably up to 6 bar, depending on the pore size, into the continuous cocoa butter-containing phase by passing it through a microporous membrane having a narrow pore size distribution. While emulsifying, the temperature is controlled such that either phase is suitably liquid. The drop size and distribution are controlled by the pore size of the membrane.

For the purpose of the invention, it is found particularly useful to use a microporous metal or glass membrane, preferably having a mean pore size between 0.05 and 0.5 μm. Good results - in terms of average droplet size - are obtained with a pore size between 0.1 and 0.3 μm. Unfortunately, throughput decreases with pore size. For industrial applicability, it is preferred that the aforementioned pore size range is combined with a pressure of 5 - 9 bar, preferably up to 8 bar.

By "microporous metal membrane" is meant any metallic layer (including "supported layer articles") having micropores and sufficient structural integrity to withstand the pressure needed to enter the emulsion as drops into the continuous fat phase, as for instance disclosed in GB-A-2,385,008. According to GB-A-2,385,008, metal micro filters have a pore size and pore size distribution which is much more defined than for commercially available microfilter membranes made from polymers or alumina (or other ceramic materials). In addition, these other source micro filters are often only available for use at laboratory scale due, in part, to the small areas available. Ceramic filters are also extremely fragile.

In a preferred embodiment, the microporous membrane is glass-made, such as the SPG membranes that are commercially available with SPG Technology Co. Ltd.. It is known in the art to produce narrow size distribution emulsion droplets and can be applied for a large throughput. Pre-wetting of the membrane surface with the dispersed phase should be avoided, since deposition of the aqueous phase on the membrane leads to a reduction in flow rate and clogging. This is prevented by pretreating (prewetting) the micropore membrane with the oily phase instead, preferably by immersing or soaking the microporous membrane in the oil phase sufficiently to render the membrane hydrophobic.

Prior or during mixing at high temperature, optionally fat-soluble ingredients such as emulsifϊers, vitamins, additional fat replacers, flavorants and colorants may be added to the cocoa butter-containing phase, provided that the oily phase is in fluidic state.

During microencapsulation, the temperature is preferably maintained in the range of 20 - 60 °C, more preferably in the range of 30 - 50 °C.

Once the w/o emulsion is formed, solidification or gelation of the stabilizer is established, e.g. by cooling, or, for (amidated) LM pectins, by adding calcium ions. It is preferred that the calcium ions are mixed with the cocoa butter to prevent clogging of the membrane. The gelation makes it a true encapsulation method, thereby minimizing the aforementioned drawbacks of the added water on the overall product.

It is surprisingly found that the droplet size may beneficially be reduced even further by the additional steps of (iv) cooling the emulsion after encapsulation, preferably microencapsulation as described above, to a temperature below 10 °C, more preferably refrigerator conditions, i.e. lower than 8 °C, more preferably 2 - 7 C, for a period of at least 1 day, more preferably at least 2, 3, 4 days, preferably up to 8 days; (v) melting the cooled emulsion; and (vi) subjecting the melted emulsion to mere agitation, preferably mixing, involving shear. This way, both the average size and the largest droplet diameter are reduced, thus preventing clogging.

Good results are obtained if the intermediate cooling step is performed in a refrigerator for 5 days, and the cooled emulsion is then sheared at 5,000 - 20,000 rpm, more preferably at least 8,000 rpm, for instance using a conventional UltraTurrax. The mixing step may be performed at a temperature in the range of 20 - 60 °C, preferably 30 - 50 °C. The mixing step preferably involves 5 - 15 Pa.

The intermediate cooling step is essential to be able to break the droplets in a subsequent shearing step. Therein, it was found that some kind of settling time is required for the cooling to take effect. It was found that beyond 5 days no additional effects were observed. The invention further pertains to the use of the aforedescribed membrane emulsification, and optionally the subsequent cooling, storage, melting and agitation steps, for the manufacture of reduced calorie cocoa butter compositions, and to the manufacture of chocolate food applications, such as chocolate confectionary made therefrom. Chocolate food products, especially chocolate confectionary may be prepared according to the invention by replacing conventional high-caloric cocoa butter with the cocoa butter composition of the invention. Although the term "chocolate" is in some countries only used for products fulfilling certain requirements, in the specification it is intended to cover all solid, edible fat products based on cocoa, i.e. cocoa powder or cocoa liquor, whether or not the fat is partly cocoa butter.

The replacement ratio may be 1 :1. With the present reduced calorie cocoa butter composition it is possible to replace at least 50 %, more preferably at least 75 %, most preferably at least 90 %, in particular all of its high caloric counterpart in the chocolate food application, without affecting the organoleptic and physical properties traditionally associated with cocoa butter.

EXAMPLES

Example 1 1) pectin solution (Solution A):In a 2 liter beaker with suspended magnetic stirrer a mass of 0.494 liter distilled water was placed and heated up to 80⁰C. The inner bar could rotate freely from the supports and it was stirred at a rate sufficient to provide an air vortex.

A mass of 6 g pectin (Geni LM- 104AS from CP KELCO) was very slowly added to the stirred water. To cool the solution it was left stirring with the heater turned off.

The stock pectin was left overnight for swelling.

2) Gum, sugar, and calcium solution (Solution B): A mass of 59.5 g water was put into a beaker and a magnetic stirrer added. The water was heated up no more than 80⁰C A mass of 0.4g Gum Arabic (ACROS 258852500) was added slowly whilst stirring rapidly. When the Arabic gum dissolved 7g of polydextrose (LITESSE II 104578-V- 4W2901 from Phizer/Danisco), 3 g inuline (Raftilose from ORAFTI ), 6.99 g sodium hydrogen phosphate, and 0.033 g calcium chloride (ACS reagent grade) was added, the pH was adjusted to about 3.2 using 2M citric acid.

Operating Procedure : 30 g of solution A and 70 g of solution B were added to 63 g cocoa butter (Callebaut

CB), 30 g polyglyceryl ester as cocoa butter hardener (BELCO 12579A8) and 7 g GPR

(Grindsted PGPR 90 Pfizer/Danisco).

Thereto, the two solutions were heated up to 80⁰C in separate containers with loose fitting lids and agitated by magnetic stirrer. After mixing of solutions A and B for 5 minutes the temperature is dropped to 45 - 50⁰C and a gel is obtained, which is of an acceptable consistency for injection into the cocoa butter continuous phase that has been heated to 400 °C. The temperature of the solutions is maintained at 80⁰C during injection, at an injection rate of 1.5ml per min per 1 cm of membrane tube length was used. For injection, an electronically induced vibrator was used as test rig, which moved the injection tube with diameter 10-14mm with slotted 5μm pores, in a linear direction, creating shear at the surface of the membrane,

A W/O emulsion was obtained of 50 %water droplets, the remainder being the continuous phase, wherein the droplets had an average size 3 μm and a size distribution between l-5μm with less than 2% between 5 and lOμm. Its caloric content was

4.8kcal/g.

Comparitive example I

An attempt was made to create the W/O emulsion using a mixer alone from the same materials. All steps in example 1 are repeated, except for the use of a membrane filter to incorporate the aqueous phase into the chocholate. In this case droplets of 50μm in diameter appeared and in the final sample very large drops developed, since non- Newtonion rheology hinders the break-up of the larger drops. In industrially scaled reactors it is expected that the drop size will be even worse. Comparitive example II

A w/o emulsion was prepared from water and cocoa butter, with a 50/50 distribution.PGPR was added to the cocoa butter as an emulsifϊer, and 1 % pectin was used as a stabilizer in the aqueous phase. Further, 0.8 % CaCl₂ was used. Firstly, pectin was dissolved in water and then the salt was added.

The emulsifϊcation involved a) mixing with a rotor- stator device; or b) hydrophobic microencapsulation. The w/o emulsion thus obtained was analysed afterwards for droplet size, using laser diffraction, and stability. In all cases, temperature was maintained at 40 °C.

a) An UltraTurrax, a very high shearing device was employed, at 16,000 rpm for 5 minutes. This is the same device as that taught in the examples of US 6,010,735. A broad and even distribution of particles between 0.1 - 60 μm were found.

b) Microencapsulation was performed using a hydrophobic glass membrane of 0.2 μm size (SPG Technology co. ltd., Miyazaki (Japan)), at a pressure of 7 bar and a flow rate of the continuous phase of 1 g/s.

Although large droplets of 20 μm were still to be found, a very distinct peak at about 150 nm was observed.

To find out about the stability of the emulsions produced by the methods of a) and b), the emulsions thus prepared were stressed by mechanical energy input directly after processing and after one week. In-between, the samples were stored in a refrigerator and melted and heated again to 40 ⁰C after one week.

Example 2

The emulsion obtained in step b) of comparative example II was cooled at 5 °C for 5 days. Then, the cooled emulsion was heated and melted again at 40 °C, and subjected to an additional mixing step using UltraTurrax (11,000 rpm; 10 minutes). The droplet size measurements showed that the additional mechanical energy input directly after processing decreases the droplet size further. The maximal droplet size was lowered significantly close to 3 μm, and 95 vol% of the droplets had a size between 0.1 and 0.2 μm. In fact, 98 vol% had a size smaller than 1 μm.

Claims

1. A reduced calorie cocoa butter composition, being a w/o emulsion containing an aqueous dispersion of solidified droplets containing a hydrophilic colloidal stabilizer in a continuous phase containing cocoa butter, wherein the average droplet size is between 0.1 and 15 μm.

2. The reduced calorie cocoa butter composition according to claim 1, being a monodisperse emulsion wherein at least 95 vol% of said droplets have a size within a range of 0.05 - 15 μm.

3. The reduced calorie cocoa butter composition according to claim 2, wherein at least 95 vol% of said droplets have a size within a range of 0.05 - 1 μm.

4. The reduced calorie cocoa butter composition according to any one of the preceding claims, wherein said hydrophilic colloidal stabilizer is pectin.

5. The reduced calorie cocoa butter composition according to any one of the preceding claims, wherein said droplets further water-soluble fat-replacing carbohydrates.

6. The reduced calorie cocoa butter composition according to claim 5, wherein said fat-replacing carbohydrates are polydextrose and/or inulin.

7. The reduced calorie cocoa butter composition according to any one of the preceding claims, wherein the volume ratio of said continuous phase to said aqueous dispersion is between 3:1 and 1 :2.

8. A process for preparing the reduced calorie cocoa butter composition by (i) providing cocoa butter at a temperature above its softening point, (ii) emulsifying an aqueous composition containing a hydrophilic colloidal stabilizer into said cocoa butter, at a temperature of at least the softening temperature of the cocoa butter or the gelling temperature of the hydrophilic colloidal stabilizer, whichever is higher, wherein said emulsifϊcation comprises a membrane encapsulation step in which said aqueous composition is emulsified under pressure into said cocoa butter by passing it through a microporous membrane, to obtain a w/o emulsion in which the continuous phase contains cocoa butter, and (iii) solidifying the dispersed aqueous phase therein.

9. The process according to claim 8, further comprising the steps of (iv) cooling the emulsion to a temperature below 10 °C for a period of at least 1 day; (v) melting the cooled emulsion; and (vi) subjecting the melted emulsion to agitation.

10. The process according to claim 8 or 9, wherein said microporous membrane is made of metal or glass.

11. The process according to any one of claims 8 - 10, wherein said microporous membrane has a mean pore size between 0.05 and 0.5 μm.

12. The process according to any one of claims 8 - 11, wherein said hydrophilic colloidal stabilizer is completely dissolved in the aqueous composition prior to adding said aqueous composition to said cocoa butter.

13. A chocolate food product containing the reduced calorie cocoa butter composition according to any one of claims 1 - 7 or prepared by the process according to any one of claims 8 - 12.

14. Use of membrane emulsifϊcation in reduced calorie chocolate manufacture.