Self-foaming soluble coffee beverage powder

Abstract: The invention relates to a soluble coffee beverage powder, which, upon the addition of water, is capable of forming a coffee beverage having a foamed upper surface. The soluble coffee beverage powder comprises a soluble gas containing matrix comprising soluble coffee solids and a soluble filler, the soluble filler constituting at least about 35% by weight of the dry matter of the matrix and is effective to increase the volume of the soluble coffee beverage powder incorporating gas. A particular preferred filler have been found to be oligofructose that has a good solubility and which positively influences on the taste of the prepared coffee beverage. The invention also relates a soluble coffee beverage powder providing a black foamed coffee. Furthermore, the invention provides a process for preparing such a soluble coffee beverage powder.

Description: Field of the Invention This invention relates to a soluble coffee beverage powder that, upon the addition of water, is capable of forming a coffee beverage having a foamed upper surface. In particular the invention relates to a soluble beverage powder, which upon reconstitution provides a beverage, which closely resembles a freshly brewed coffee. The invention also relates to a process for making such a product. Background to the Invention Soluble coffee beverages product are well known product, which upon the addition of water (usually hot) provides a coffee beverages. It is also well know to mix the soluble coffee powder with soluble creamer or whitener powders to produce whitened coffee beverages. These classical soluble beverage products are coffee beverages without any foam on the upper surface. Soluble coffee beverage products of the instant "cappuccino" type are also known and are commercially available. Usually these products are dry mixes of a soluble coffee powder and a soluble whitener powder. The soluble whitener powder contains pockets of gas, which, upon dissolution of the powder, produce foam. Therefore, upon the addition of water (usually hot), a whitened coffee beverage, which has a foam on its upper surface, is formed; the beverage resembling, to a greater or lesser extent, traditional Italian cappuccino. In coffee bars and restaurants it is usual to serve freshly brewed black coffee which is prepared on the basis of roast and grounds. The freshly brewed black coffee is characterised by a light brown foamy layer that covers the upper surface of the beverage. The coffee is usually prepared on an espresso type of machine on which one may e.g. brew a short strong espresso or a larger cup of black coffee. Non of the existing foaming soluble powders provides a coffee beverage that resembles freshly brewed roast and ground black coffee beverages of the above-described type. This type of freshly brewed espresso is characterised by a light brown foamy layer, which covers substantially all the surface of the beverage. There is a need for an alternative to the above-discussed soluble beverage powder and a soluble beverage powder, which upon reconstitution provides a beverage, which closely, assimilates a freshly brewed espresso or black coffee. Summary of the Invention Accordingly, in one aspect, the invention provides a soluble coffee beverage powder which, upon the addition of water, is capable of forming a coffee beverage having a foamed upper surface, the soluble coffee beverage powder comprising: a soluble gas containing matrix comprising soluble coffee solids and a soluble filler being oligofructose, the soluble filler constituting at least 35% by weight of the dry matter of the matrix and is effective to increase the volume of the soluble coffee beverage powder incorporating gas. It is surprisingly found that the soluble beverage powder according to the invention upon the addition of water may provide a foamed black coffee with foam on it upper surface. In texture, colour and mouthfeel the foamed beverage product of the invention has foam that is comparable to that of a freshly brewed espresso prepared from roast and g round espresso machines. The high quantity of soluble foamer, at least 35%, preferably from about 45% by weight of the dry matter of the soluble matrix are effective to increase the volume of the soluble coffee beverage powder into which gas may be incorporated. By increasing the powder volume and thus the amount of gas incorporated in the beverage powder a cup with a higher foam volume may be achieved. Thus the soluble filler is added for that purpose. This has further the advantage that a high foam volume is more stable than a small on which means that the foam stays longer on the surface of the beverage. In the invention the soluble filler is oligofructose. It has been found that large amounts of oligofructose may be added without any major impact on the products taste profile. Further, it has surprisingly been found that the oligofructose may reduce unpleasant coffee notes like acidity, harshness and astringency of the product. This allows a coffee with milder taste profile to be made without the addition of creamer. In addition oligofructose has been found to be particular suitable as a soluble filler due to its good solubility and high dissolution velocity. A preferred product according to the invention is a self-foaming black coffee powder, which is soluble in hot water. After reconstitution, the product forms a layer of foam on the product surface, which covers the whole surface of the beverage and which is stable for a period of time. The product of the invention may be made substantially free from dairy or creamer components. However, if desired milk components may also be added. In another aspect, this invention provides a soluble coffee beverage powder comprising a soluble matrix comprising soluble coffee solids and a soluble filler, which soluble matrix comprising gas for foaming, characterised the soluble filler is effective to increase the gas incorporation volume of the matrix and in that the soluble coffee beverage powder, upon the addition of water, is capable of forming a black coffee beverage having a foamed upper surface. In a further aspect, this invention also provides a process for providing a soluble coffee beverage powder which, upon the addition of water, is capable of forming a coffee beverage having a foamed upper surface, comprising providing soluble coffee solids constituting at least 35% by weight of the dry matter of the powder, providing a soluble filler being oligofructose constituting at least 35% by weight of the dry matter, the oligofructose is effective to increase the volume of the soluble beverage powder capable of incorporating gas, mixing the soluble coffee solids and the oligofructose with a liquid to a mixture and incorporating gas into the mixture, and drying the mixture into a powder containing gas for foaming the coffee beverage. Detailed Description of Preferred Embodiments of the Invention Embodiments of the invention are now described, by way of example only. According to the invention the beverage powder has a soluble gas-containing matrix comprising soluble coffee solids and soluble filler. By combining the soluble coffee solids and the soluble filler in a matrix the product volume increases allowing more gas to be entrapped. Hence, more air bubbles will be available in the coffee after adding hot water and more foam bubbles will be formed. Furthermore, a homogeneously coloured product is obtained. In preference the soluble filler constitutes at least 35% by weight of the dry matter of the matrix to be effective to substantially increase the volume of the soluble coffee beverage powder incorporating gas. Further, it is preferred the soluble gas containing matrix includes at least 35% soluble coffee solids by weight of dry matter. Advantageously, the matrix includes from 35 to 65% soluble coffee solids and/or from 35 to 65% soluble filler by weight of dry matter. Preferably, the matrix includes from 45 to 60% soluble coffee solids and/or form 40 to 55% soluble filler by weight of dry matter. This allows the gas incorporation to about the double of what could have been entrapped in the coffee solids alone. With soluble filler content below 35% by weight of dry matter, the reconstituted beverage product may not have a sufficiently foamed upper surface. Above the 65% by weight of dry matter of soluble filler an off taste of the filler may be present. If the quantity of filler is modified, the concentration for the finished product (g/150ml water) is preferably adjusted. The concentration of the coffee dry matter in the cup should preferably be the same for all possible concentrations of filler in the powder. For the preparation of the beverage powder coffee solids is conveniently provided in coffee liquor. The coffee liquor may be obtained using any suitable procedure. Usually, the coffee liquor is prepared by concentrating a coffee extract obtained from a coffee extraction process to the desired coffee concentration. The coffee extract may be produced in the usual manner by subjecting roasted coffee beans to extraction. Any suitable extraction procedure may be used because the choice and design of the extraction procedure is a matter of preference and has no critical impact on the invention. Suitable extraction procedures are described in European patent applications 0826308 and 0916267. Similarly, any suitable concentration procedure may be used because the choice and design of the concentration procedure is a matter of preference and has no critical impact on the invention. Of course, the coffee liquor may also be prepared by dissolving soluble coffee powder in water to the desired concentration. The color of the foam bright brown foam without any lumps strongly depends on a perfect solubility of the powder. A suitable soluble filler is a filler, which has a good solubility for example a solubility close to that of soluble coffee. Further the filler may conveniently be neutral in taste or add some sweetness to the final beverage powder. The soluble filler is preferably a filler selected from the group of oligosacchrides. Examples of fillers are Maltodextrin and oligofructose. Oligofructose has been found to be particular preferred. Although the oligofructose has no particular foam stabilising effect, it is perfectly soluble and may be added e.g. up to 45 % (related to dry matter) without changing the cup profile. This means that the powder quantity and volume can nearly be doubled without changing the product in taste and this is the main idea of the addition. A filler, which has been found not to be suitable for the present purpose, is Inulin, which although it has a foam stabilising effect is not suitable due to bad solubility and low dissolution velocity. The difference between inulin and oligofructose is the degree of polymerisation DP (number of connected molecules). The DP of inulin lies between 2 and 60, whereas the DP of oligofructose is between 2 and 20. The properties of the two ingredients are different, and oligofructose cannot be replaced by inulin. Advantageously, the oligofructose has a degree of polymerisation between 2 and 8. A suitable oligofructose may be obtained from Raftilose (Orafti). To minimise the impact on the cup profile, it is desirable that the oligofructose has a concentration of mono- and disaccharides in the range from 3% to 7%. A positive side effect of the high amount of oligofructose is that the beverage of the invention may have a prebiotic effect. A prebiotic effect may possible be achieved at a daily dose of 6g oligofructose. This corresponds to a consumption of 3 to 4 cups of beverage a day. The soluble coffee beverage powder may also include a soluble sweetener; natural or artificial. Suitable examples include sucrose, fructose, lactose, maltose, saccharin, cyclamates, acetosulfame, L-aspartyl based sweeteners such as aspartame, and the like, and mixtures of these. The amount of the sweetener used will vary depending upon the desired level of sweetness and the strength of the sweetener. However for sugar based sweeteners, the total amount of sweeteners is usually in the range of 10% to 25% by weight. The soluble sweetener may also be combined with bulking agents such as maltodextrins and polydextrose; particularly if an artificial sweetener is used. In this case, the total amount of sweetener and bulking agent is usually in the range of 10% to 25% by weight; artificial sweetener itself usually comprising less than 1% by weight. For a sweet variety of the soluble beverage powder according to the invention, a more sweet type of oligofructose may also be selected. An oligofructose with up to 45 % mono- and disaccharides is particular suitable for this purpose. Alternatively, the soluble beverage powder may be dry mixed with sugar. In order to get a homogeneous coloured product brown sugar may dry mixed with the soluble beverage powder. The brown sugar furthermore provides a pleasant complement to the coffee taste. In a preferred embodiment of the invention the soluble coffee beverage powder consists of soluble coffee solids and soluble filler and not other ingredients. For example a mild soluble beverage powder may be made without the need for a creamer component. In this embodiment the beverage powder conveniently does not contain dairy components which could act as a creamer. It may nevertheless be desirable to add for proteins from milk or other sources to influence the foamability of the product. The addition should however be of a very small quantity to avoid any modification of the coffee colour. To produce the soluble beverage powder the soluble filler is mixed with a liquid to a solution. The solution is then combined with the coffee liquor. Alternatively, the soluble filler is mixed directly into the liquor. The mixture is heated for example to above 50°C, and is then mixed to a homogeneous solution. Subsequently, the mixture may be gassed by injecting of a gas such as nitrogen or carbon dioxide into it. The gas is then dispersed within the mixture by means of a dispersing machine and the gassed mixture is then passed onto a homogeniser. The gassed and homogenised mixture is then spay dried in a conventional manner. The spray dried powder has a matrix comprising the soluble filler and the soluble coffee solids. The spray drying may conveniently take place in a spray drying tower having for example a Schlick spray nozzle. The pressure in front of the nozzle is preferably in the range from 45 to 70 bars and the temperature in the tower is preferably in the range from 85 to 95 °C. Subsequent to the drying, the powder may be cooled in a fluidized bed cooler and leaves a final sieve with a temperature of 20°C. It is preferred that the tapped specific gravity of the powder is in the range from 150 to 250g/l, more preferred is a tapped specific gravity between 200 and 220 g/l. Tapped specific gravity is referring to the gravity of the powder when compressed by vibrating the powder with 100 pushes of 10mm. Example 1 - Preparation of Coffee Beverage Powder Samples of coffee beverage powder according to the invention is prepared as follows: Conventional coffee liquor of 44 to 46 % dry matter is mixed in the ratio 55 to 45 with a solution of oligofructose in 44 - 46 % dry matter. The solution of oligofructose is made by mixed in demineralised water and oligofructose powder. The mixture of coffee liquor and oligofructose has a dry matter content of 44 to 46 %. The liquor is first heated to approximately 55 °C, then inline mixed with nitrogen (450 nl/h), dispersed in a dispersing machine, homogenized and put under pressure in a homogenizer and is then sprayed into a spray drying tower (approximately 600 kg/h). The pressure in front of the nozzle (Schlick) is approximately 50 bar and the temperature in the tower is 90°C. After drying, the powder gets cooled in a fluidized bed cooler and leaves a final sieve with a temperature of 20°C. The specific weight (tapped) has to be between 200 and 220 g/l. The powder obtained comprises a matrix of soluble coffee and oligofructose into which gas is incorporated. Example 2 - Preparation of Coffee Beverage Powder Samples of coffee beverage powder are prepared as in Example 1. However, a mixture of demineralized water and soluble coffee powder replaces the coffee liquor. The dry matter content of the liquor from soluble coffee powder is 25%. The oligofructose is the soluble filler. Oligofructose powder is added to the solution of coffee powder until a dry matter content of 44 to 46 % is achieved. The mixture is gassed and dried as discussed in Example 1. Example 3 - Evaluation A taste panel evaluates the samples prepared according to Example 1 and 2. The concentration of coffee beverage powder according to the invention is 2.6 %. The powder is to be put into coffee cups and hot water should be added fast. All particles are drowned. A clean bright foam surface is obtained. Milk can be added, if necessary and the beverage can be stirred without destroying the foam. After the foam formation is finished (30 s) the product is ready for consumption. The reconstituted samples according to the invention are compared with samples prepared without soluble filler but prepared with the same coffee liquor or soluble coffee powder. A triangle and a cup profile are carried out with the products. In the Triangle test three cups of coffee are presented, one is different from the others and the test panel will have to find out which one it is. In the Cup profile test two cups of coffee are presented, a reference and a sample and the test panel has to decide if they are different or not, using different defined characteristics like bitter, acid and so on. Cup profiles are always in comparison to a reference. The triangle test shows that the product with oligofructose is in taste does not significantly different from pure soluble coffee beverage. Only the cup profile show slightly differences in odour- and general taste intensity. The reconstituted samples according to the invention are compared with freshly brewed espresso prepared on roast and ground in a conventional coffee machine. The coffee beverage according to the invention has light brown foam on the whole surface, which is 5 to 10 mm thick, in a cup having a diameter of 74 mm. The thickness of the foam depends on the diameter of the cup. The foam clearly resembles that of the freshly brewed cup. It remains substantially stable for a period of more than 3 minutes.

Claims: A soluble coffee beverage powder which, upon the addition of water, is capable of forming a coffee beverage having a foamed upper surface, the soluble coffee beverage powder comprising: a soluble gas containing matrix comprising soluble coffee solids and a soluble filler being oligofructose, the soluble filler constituting at least 35% by weight of the dry matter of the matrix and is effective to increase the volume of the soluble coffee beverage powder incorporating gas. A soluble coffee beverage powder according to claim 1, in which the soluble gas containing matrix includes at least 35% soluble coffee solids by weight of dry matter. A soluble coffee beverage powder according to any of claims 1 and 2, in which the matrix includes from 35 to 65% soluble coffee solids and/or from 35 to 65% soluble filler by weight of dry matter. A soluble coffee beverage powder according to any of claims 1 to 3, in which the oligofructose has a concentration of mono- and disaccharides in the range from 3% to 7%. A soluble coffee beverage powder according to any of claims 1 to 4, in which the oligofructose is a sweet type oligofructose. A soluble coffee beverage powder according to any of claim 1 to 5, in which the soluble coffee beverage powder consists of soluble coffee solids and soluble filler. A soluble coffee beverage powder according to any of claims 1 to 6, in which the soluble coffee beverage powder does not contain dairy components. A soluble coffee beverage powder according to any of claims 1 to 7, in which the soluble coffee beverage powder is spray dried. A process providing a soluble coffee beverage powder which, upon the addition of water, is capable of forming a coffee beverage having a foamed upper surface, comprising providing soluble coffee solids constituting at least 35% by weight of the dry matter of the powder, providing a soluble filler being oligofructose constituting at least 35% by weight of the dry matter, the oligofructose is effective to increase the volume of the soluble beverage powder capable of incorporating gas, mixing the soluble coffee solids and the soligofructose with a liquid to a mixture and incorporating gas into the mixture, and drying the mixture into a powder containing gas for foaming the coffee beverage.

Inventors: FRITZ MICHAEL, FRITZ, MICHAEL
Applicants: NESTLE SA, SOCIETE DES PRODUITS NESTLE S.A.
Application year: 2000
Main classification: A23F5
IPC codes: A23F5