Technical Field

The present invention relates to emulsifier systems which may be used in the manufacture of frozen dessert and which comprise at least one coffee bean extract and coffee particles. It also relates to a frozen confectionery product comprising this emulsifier system. The invention, in another aspect, concerns a method for manufacturing such frozen confectionery products. The invention finally relates to particular green and roasted coffee particles. Background of the invention

In the manufacture of frozen confectioneries, emulsifiers and stabilisers play an essential role. While stabilisers are generally used for adding viscosity, improving handling properties and also for preventing ice crystal growth, emulsifiers aid in developing the appropriate fat structure and air distribution necessary for the smooth eating and good meltdown characteristics desired in such products .

These ingredients are indispensable to the manufacture of commercially acceptable products. Efficient stabiliser and emulsifier systems already exist, but these are often based on chemically modified ingredients that do not answer the growing demand from the consumer for products which are free from artificial additives or so-called "E numbers". An example which predominate most ice cream formulations is that of mono- and di-glycerides , derived from the partial hydrolysis of fats or oils of animal or vegetable origin. There is thus a need for replacing synthetic emulsifiers by natural systems having the required tensioactive properties while not compromising on the product quality.

Natural ingredients with emulsifying properties are known, but they are usually not as efficient as synthetic emulsifiers and/or present other drawbacks.

In particular, egg yolk has been known for a long time for its emulsifying properties. EP 2185003 describes for instance a stabiliser system for frozen confectioneries comprising egg yolk as natural emulsifier associated with starch and citrus fibers. However, the use of egg yolk might be limited in some cases due to its allergen character .

Quillaia is also known for its emulsifying properties. However, this plant contains saponins which are toxic for humans at certain concentrations. Proteins have emulsifying properties but in frozen confections, it is needed to replace proteins at oil/water interface to promote partial coalescence during freezing. Therefore, native proteins alone in a recipe cannot deliver long term ice cream stability.

Several attempts for providing products which are free from artificial emulsifiers can be found in patent publications. EP 1400176 describes for example frozen aerated products which have no additional stabilisers or emulsifiers and have an overrun of 10-250%, a pH, when melted, of 3.5 to 5.2, and which comprise 0-20% fat, 0.25 to 20% milk solids not fat, 0.05 to 1.5% soluble dietary fibre and 0.1 to 5% insoluble dietary fibres coming from fruit and vegetable purees.

GB 2359727 also describes an emulsifier composition which can be used in ice creams and which comprises an emulsifier which encapsulates a disintegration improver, such as a fibre or a hydrocolloid .

Alternative and new solutions to answer this important demand for natural emulsifier systems are still needed. It is therefore an object of the invention to answer this need and in particular to provide an emulsifier for frozen confectioneries comprising natural ingredients.

Summary of the invention

Accordingly, in a first aspect, the present invention provides en emulsifier system for use in a frozen confectionery product comprising at least one coffee bean extract combined with coffee particles with a particle size comprised between 0.1 and 500 microns, preferably between 10 an 200 microns. The extract and particles are preferably selected from roasted coffee extract, respectively particles, green coffee extract, respectively particles and mixtures thereof. The coffee extract is preferably rich in macromolecules and comprises at least 40%, preferably at least 50% dry matter of macromolecules with a molecular weight comprised between 3.5 and 1600 KDa . The use of this emulsifier system in the manufacture of a frozen confectionery, and a frozen confectionery including such emulsifier system also form part of the invention.

In a further aspect, a method for the manufacture of a frozen confectionery as defined above comprising the steps of:

a. Blending a frozen confectionery ingredient mix comprising from 0.5 to 20wt% fat, from 5 to 15wt% milk solids-non-fat, from 5 to 35 wt% of a sweetening agent, up to 3 wt% of a stabiliser and from 0.1 to 10 wt% of an emulsifier system comprising at least one coffee extract and coffee particles as defined above,

b. Pasteurising and homogenising the mix,

c. Freezing while optionally aerating the mix, d. Optionally hardening the frozen mix; is provided by the present invention. Finally, coffee particles obtainable by a process which comprises

- Grinding coffee beans in liquid nitrogen;

- Performing two aqueous extractions using an ultrasound bath, then a waterbath;

- Filtrating the liquid phase from the solid part;

- Drying the solid part to provide coffee particles also form part of the invention. Detailed description of the invention

Unless otherwise specified % in the present description correspond to wt%.

The present invention concerns an emulsifier system used for a frozen confectionery product. By "emulsifier system" is to be understood at least one ingredient with tensioactive properties, which therefore contributes in developing the appropriate structure and air distribution necessary for the smooth eating and good meltdown characteristics of a frozen confection. Emulsifiers are compounds which confer to the finished product a smoother texture and stiffer body, which reduce the whipping time. The presence of emulsifiers results in air cells that are smaller and more evenly distributed throughout the internal structure of the ice cream. Emulsifiers suitable for frozen confectionery products are further defined and characterised in Robert T. Marshall, Douglas Goff and Richard W. Hartel, 2003, Ice Cream - 6th Edition, Ed.Kluwer Academic/Plenum Publishers (New York).

In the present description, what is meant by "natural ingredients" is ingredients of natural origin. These include ingredients which come directly from the field, the animals etc. They may also include ingredients which are the result of a physical or microbiological/enzymatic process (e.g. extraction, fermentation etc.). However, they do not include ingredients which are the result of a chemical modification process. According to the present invention, the emulsifier system is characterised by the presence of at least one coffee extract together with coffee particles which a particle size comprised between 0.1 and 500 microns, preferably between 10 and 200 microns. Preferably such extract and particles are selected from roasted coffee extract/particles, green coffee extract/particles and mixtures thereof. According to a particular embodiment, the extract comprises at least 40wt%, preferably at least 50wt% and preferably less than 60 wt% dry matter of macromolecules with a molecular weight comprised between 3.5 and 1600 KDa .

Those mixtures of extracts and particles have been found by the applicant as susceptible of being used in an emulsifier system for frozen confectionery products. In particular, such an emulsifier system has shown to improve melting properties of a frozen confection containing it. The emulsifier system of the invention comprises at least one coffee extract and coffee particles, preferably selected from roasted coffee extract/particles, green coffee extract/particles and mixtures thereof. In a particular embodiment the ratio between coffee extracts and coffee particles is comprised between 1: 99 and 99: 1. According to a preferred embodiment, a ratio is comprised between 40:60 and 60:40. The extract preferably comprises at least 40wt"6 more preferably at least 50 wt% dry matter of macromolecules with a molecular weight comprised between 3.5 and 1600 KDa .

Said extracts are obtainable by a method including the steps of separating an extract from a raw material using filtration, then separating the active fraction using membrane filtration, heating during the extraction and finally freeze drying to have the extract lyophilized. According to a first embodiment, the emulsifier system of the invention includes a roasted coffee extract comprising from 15 to 35 wt%, preferably from 20 to 30 wt% dry matter of polysaccharides; and from 15 to 30 wt%, preferably from 20 to 25 wt% dry matter of melanoidins proteinous part.

The polysaccharides present in this extract can be further characterised by a specific carbohydrate profile. Preferably, the extract comprises from 5 to 7 wt% dry matter of arabinose, from 10 to 13 wt% dry matter of galactose, from 9 to 10 wt% dry matter of mannose, from 0.1 to 1 wt% dry matter of glucose, from 0.2 to 1 wt% dry matter of rhamnose.

Typically, roasted coffee extracts used in the system according to the invention have a roasting degree comprised between CTn 80 and CTn 100.

Preferably, the extract has a solubility limit of 2 mg/ml. According to a second embodiment, the emulsifier system of the invention comprises at least one green coffee extract comprising from 5 to 25 wt%, preferably from 10 to 20 wt% dry matter polysaccharides and from 35 to 50 wt%, preferably from 40 to 45 wt% dry matter of proteins with a molecular weight comprised between 3.5 and 500 KDa . Green coffee extracts used in the emulsifier system of the invention preferably comprise from 2 to 3 wt% dry matter of arabinose, from 5 to 7 wt% dry matter of galactose, from 1 to 2 wt% dry matter of mannose, from 1 to 4 wt% dry matter of glucose, from 0.2 to 1% wt% dry matter of rhamnose and from 1 to 2wt% dry matter fructose.

Preferably said green coffee extract has a solubility limit of 0.5 mg/ml. The coffee particles from the emulsifier system of the invention have a particle size comprised between 0.1 and 500 microns, preferably between 10 and 200 microns.

According to a particular embodiment, the coffee particles are green coffee particles and comprise from 10 to 15wt% dry matter proteins and from 10 to 20 wt% dry matter polysaccharides .

According to another embodiment, the coffee particles are roasted coffee particles and comprise from 10 to 20 wt% dry matter melanoidins proteinous part and from 10 to 20 wt% dry matter polysaccharides.

The emulsifier system of the invention may be used in the manufacture of a frozen confectionery. For example, it may be used in the same way as traditional emulsifier systems in the manufacture of ice cream, sherbet, frozen yogurt, milk ice, mellorine etc. It presents not only the advantage of improving melting properties of such products, but also the advantage that it contains natural ingredients .

The invention therefore pertains to the use of an emulsifier system as described above in the manufacture of a frozen confectionery product, in particular for improving the melting properties of such product.

A frozen confectionery product comprising an emulsifier system comprising at least one coffee extract and coffee particles is also an object of this invention. Preferably, the frozen confectionery product comprises from 0.1 to 10 wt%, preferably from wt% of the emulsifier system.

Frozen confectionery products according to the invention include products such as ice cream, sherbet, frozen yogurt, mellorine, ice milk, frozen shake and other frozen dessert.

They typically include from 0.5 to 20 wt%, preferably from 8 to 12 wt% fat, from 1 to 20%, preferably from 5 to 15% milk solids-non-fat, from 5 to 35 wt%, preferably from 10 to 30 wt% of a sweetening agent and up to 3wt% of stabilisers .

According to a particular embodiment, the frozen confectionery products of the invention are aerated with an overrun ranging from 20 to 250%, preferably from 80 to 150%, more preferably from 100 to 120%. The overrun is defined as follows: (Reference : Robert T. Marshall, Douglas Goff and Richard W. Hartel, 2003, Ice Cream - 6th Edition, Ed.Kluwer Academic/Plenum Publishers (New York), ISBN 0-306-47700-9, page 144.) wt of mix - wt of same vol. of ice cream

%overrun = - , τ· ^{1 00}

wt of same vol. of ice cream

The fat present in the frozen confection according to the invention can be from dairy or vegetable source. Suitable dairy fat include fresh cream, sour cream, cultured cream, buttermilk and milk fat. Vegetable fats such as cocoa butter, coconut oil, hazelnut oil, palm oil, rapeseed oilm soybean oil, palm kernel oil, sunflower oil, fractions and mixtures thereof can also be used.

The frozen confectionery product of the invention also includes serum solids or milk solids-non-fat which contain the lactose, caesins, whey proteins, minerals, and ash content of the product from which they were derived. Typically skim milk powder or condensed skim milk are used. As an alternative, milk powders replacers such as blends of whey protein concentrates, caseinates or whey powders can also be used. The frozen confection product according to the invention further includes a sweetening agent. "Sweetening agent" is meant to designate at least one ingredient which imparts sweetness to the final product. Sweetening agents include sugars such as sucrose, glucose, fructose, lactose, dextrose, invert sugar either crystalline or liquid syrup form, or mixtures thereof, which can be used in admixture with sweeteners such as corn sweetener in either a crystalline form of refined corn sugar (dextrose and fructose) , a dried corn syrup (corn syrup solids) , a liquid corn syrup, a maltodextrin, glucose, or a mixture thereof. Natural sugars like cane sugar, beet sugar, molasses, other plant derived nutritive sweeteners and natural non-nutritive high intensity sweeteners as well as mixtures thereof can also be used in the framework of the invention .

The product also includes up to 3% of stabilizers. Suitable stabilizers include for example agar, gelatin, gum acacia, locust bean gum, guar gum, carboxymethyl cellulose (CMC) , xanthan gum, sodium alginate, carrageenan or any mixture of hydro-colloids.

Other conventional ingredients such as mineral salts, colorants, flavorings, inclusions, etc. can be present in the products of the invention

The invention further pertains to a method for the manufacture of a frozen confectionery product. Said process can be carried out using conventional equipment. The first step consists in blending an ingredient mix comprising from 0.5 to 20 wt% fat, from 5 to 15 wt% milk solids-non-fat, from 5 to 35 wt% of a sweetening agent and up to 3wt% stabilizers with 0.1 to 10 wt% of an emulsifier system comprising at least one coffee bean extract and as defined above. One of ordinary skill in the art can determine mixing time and conditions to obtain the desired homogeneous mass. Thereafter, the homogeneous mass is preheated, e. g., to a temperature of about 62°C to about 75°C. The preheated homogeneous mass is conventionally homogenized, e. g., in a two stage homogenizer. The first stage is conducted at a pressure of about 70 bar to about 250 bar, preferably of about 100 bar to about 150 bar, more preferably about 150 bar. The second stage is conducted at a pressure of about 0 bar to about 50 bar, preferably of about 20 bar to about 35 bar. Subsequently, or preceding the homogenisation, pasteurization is conducted under conditions commonly used in the industry. The pasteurization step is conducted typically at a temperature of about 50°C to about 100 °C, preferably of about 60 °C to about 85 °C for a time of about 10 seconds to about 30 minutes, preferably for time of about 30 seconds followed by cooling to a temperature of about 0 °C to about 10 °C, preferably at a temperature of about 4 C. Preferably, pasteurization is conducted by either high temperature short time (HTST) or low temperature long time (LTLT) processing.

After pasteurization, the coffee particles are added to the mix and then the mix is preferably aged, preferably with agitation by allowing to stand at a temperature of about 0 °C to about 6 °C, preferably of about 1°C to about 5°C and for a time of about 1 hour to about 24 hours, preferably of about 2 hours to about 18 hours and more preferably of about 4 hours to about 12 hours.

The mix is then colored and flavored as needed.

In the next step, the mix is optionally aerated. In a preferred embodiment, the mix may be cooled to a temperature below -3°C, preferably between -3 and -10°C, preferably at about -4.5 to -8°C with stirring and injection of gas to create the desired overrun. The frozen confectionery is preferably aerated to an overrun comprised between 20 and 250%, preferably between 80% to 150%, more preferably between 100% to 120%.

The aerated mix can be subjected to freezing either by using conventional freezing equipment or by a low temperature extrusion system. In this equipment, the aerated mix is cooled by extrusion at a temperature of below -11°C, preferably between -12°C and -18°C in a screw extruder. The screw extruder may be such as that described in WO 2005/070225. The extrusion may be performed in a single or twin screw extruder.

The frozen mix is then packaged and stored at temperatures below -20°C, where it will preferably undergo hardening step during storage. Alternatively, it can be hardened by accelerated hardening step, for example via a hardening tunnel, carried out at a temperature between -20°C to - 40°C for a sufficient time to harden the product. The coffee particles that can advantageously be used in the emulsifier system of the inventions are also an object of the invention. They are obtainable by a process comprising grinding coffee beans in liquid nitrogen; performing two aqueous extractions preferably using an ultrasound bath, then a water bath; filtrating the liquid phase from the solid part and drying the solid part to provide coffee particles. Figures

Figure 1: flow chart of a process for the preparation of coffee extracts and coffee particles used in the present invention .

Examples

Example 1

Coffee extraction and particle preparation Figure 1 is a flow chart of the process.

Green coffee beans, respectively roasted coffee beans with a roasted degree of CTn 90 were subjected to the following steps :

Extraction steps and particle preparation

1. Grinding of coffee raw material in liquid nitrogen .

2. Adding hot water 90°C (± 5 °C) to the ground coffee raw material placed in an ultrasound bath for 30 minutes (± 2 minutes) .

3. Filtration under vacuum (Buchner-type filtration), followed by filtration in a spinner at 2200 rpm for 20 minutes (filter pore size: 20-50 microns) . Keep the liquid phase.

4. Place the solid part in hot water 90°C (± 5 °C) with stirring (waterbath shaker) for 60 minutes (±

10 minutes) . Note: add 2.5 L hot water (± 0.1 L) .

5. Filtration under vacuum (Buchner-type filtration), followed by filtration in a spinner at 2200 rpm for 20 minutes (filter pore size: 20-50 microns) . Keep the liquid phase.

6. Combine the two liquid phases, evaporate using a rotary evaporator, and reduce the water volume to 6 L (± 1 L) .

7. Dry the particles at room temperature under fume hood for 24 hours. Filtration through a dialysis membrane to get the active fraction

1. Isolate the coffee fraction with the molecular weight equal or higher than 3.5 KDa using dialysis tubing (cut-off: 3.5 KDa) . Dialyse for 2 days in tap water in a cold room (4-8 °C) with 2 water exchanges per day (every 3 hours ± lhour) . Note: use 10 L tap water (± 0.5 L) for 1.5 L coffee fraction .

2. Freeze-dry the coffee extract for 2 days.

3. Store the extract at -20°C.

Example 2

Coffee extracts and particles characterization

2.1 Green coffee extracts

The green coffee extract obtained from the method described in Example 1 was characterized in terms of protein molecular weight using size exclusion chromatography. Protein molecular weights were found ranging from 3.5 to 470 KDa. Said extract had a protein concentration ranging from 40 to 45 wt% dry matter and a polysaccharide concentration ranging from 11 to 17 wt% dry The total carbohydrate content was determined ionic chromatography:

2.2 Roasted coffee extracts

The roasted coffee extract obtained from the method described in Example 1 was characterized in terms of melanoidins molecular weight using size exclusion chromatography. Melanoidins molecular weight were comprised between 3.5 and 1600 KDa Said extract had a melanoidins concentration ranging from 19 to 25 wt% dry matter and a polysaccharide concentration ranging from 26 to 29 wt% dry matter. The total carbohydrate content was determined using ionic chromatography:

Compounds % of dry

matter

Arabinose 5.1 - 6

Galactose 10.9 - 12

Mannose 9.4 - 9.5

Glucose 0.2 - 0.5

Rhamnose 0.6 - 0.7 2.3 Green coffee particles

Particles obtained by a process as described in Example 1 had a protein concentration ranging from 12 to 13 wt% dry matter and a polysaccharide concentration ranging from 15 to 18 wt% dry matter. The total carbohydrate content was determined using ionic chromatography:

Lipid content: 8.5% dry matter

Particle size: 100 - 200 microns

2.4 Roasted coffee particles

Particles obtained by a process as described in Example 1 had a melanoidins proteinous part concentration ranging from 14 to 15 wt% dry matter and a polysaccharide concentration of 15 wt% dry matter. The total carbohydrate content was determined using ionic chromatography:

Compounds % of dry

matter

Arabinose 0.57

Galactose 5.3

Mannose 6.7

Glucose 2.4 Lipid content: 5.9% dry matter. Particle size: 100 - 200 microns Example 3

Frozen confectionery product comprising an emulsifier system based on coffee extracts and coffee particles A frozen confectionery product was prepared based on the following ingredients mix:

Ingredients Wt% of final product

Fat dairy cream 8,4

Sugar 23.2

MSNF 9.7

Roasted coffee extract* 0,11

Green coffee particles from 0,11

spent coffee*

Stabilizes: guar, LBG 0,16

Total solids 40,41

Ingredients Wt% of final product

Fat dairy cream 8,4

Sugar 23.2

MSNF 9.7

Green coffee extract* 0,11

Green coffee particles from 0,11

spent cofee*

Stabilizers: guar, LBG 0,16

Total solids 40,41 * as described in examples 1 and 2.

The blank recipe contains the same base of ingredients mentioned before except for coffee extract and particles. Process conditions

All ingredients except the coffee particles, were mixed at 65°C followed by a pasteurization step with a heat plate exchanger at 86°C 30", then the mix was homogenised in a 2 step high pressure homogenizer at 150 and 40 bar. Then the coffee particles were added to the pasteurized- homogenised mix and then aged for 24 h at 4°C with continuous stirring. The mix was then whipped at -7.5 to obtain overrun of 105% in conventional freezing equipment. The aerated frozen confection was then filed into containers and then hardened at -30°C to finalize the freezing .

Results :

Drip test _ Heat shocked samples

The drip test results show that the use of mixtures of coffee extracts + coffee particles provide melting resistance by reducing the loose of weight when samples is submitted to room temperatures.