SPRAY-DRIED COFFEE PRODUCT AND PRODUCTION METHOD

Abstract

The present invention relates to a method of producing a coffee powder, the method comprising: a) providing an aqueous coffee extract comprising from 30 to 55 wt % soluble coffee solids and from 1 to 10 wt % oil, wherein the aqueous coffee extract consists of water and coffee-derived components; b) subjecting the aqueous coffee extract to a two stage homogenisation process, wherein the first stage is conducted at 200 to 1000 Bar and the second stage is conducted at 10 to 100 Bar, to provide a homogenised coffee extract; c) spray-drying the homogenised coffee extract.

Claims

1: A method of producing a coffee powder, the method comprising: a) providing an aqueous coffee extract comprising from 30 to 55 wt % soluble coffee solids and from 1 to 10 wt % oil, wherein the aqueous coffee extract consists of water and coffee-derived components; b) subjecting the aqueous coffee extract to a two stage homogenisation process, wherein the first stage is conducted at 200 to 1000 Bar and the second stage is conducted at 10 to 100 Bar, to provide a homogenised coffee extract; c) spray-drying the homogenised coffee extract.

2: The method according to claim 1, wherein the aqueous coffee extract comprises from 1.5 to 5 wt % coffee oil.

3: The method according to claim 1, wherein the aqueous coffee extract is an aromatised coffee extract and is provided by: (i) providing roast and ground coffee; (ii) contacting the roast and ground coffee with water to form a coffee composition; (iii) subjecting the coffee composition to an aroma-separation step to recover a coffee aroma fraction and to form a dearomatised roast and ground coffee, wherein the aroma-separation step recovers from 1 to 15 wt % of the coffee composition as the coffee aroma fraction; (iv) subjecting the deaeromatised roast and ground coffee to one or more aqueous extraction steps to provide an intermediate coffee extract having 35 to 70 wt % coffee solids; (v) adding the coffee aroma fraction to the intermediate coffee extract to form the aromatised coffee extract.

4: The method according to claim 3, wherein the aromatised coffee extract contains the coffee aroma fraction and the intermediate coffee extract in a weight ratio of coffee aroma fraction to intermediate coffee extract of from 2:5 to 1:20.

5: The method according to claim 3, wherein: the roast and ground coffee provided in step (i) has a mean particle size of from 100 to 600 microns, step (ii) comprises mixing the roast and ground coffee with water to form a first slurry containing 15 to 30 wt % coffee solids, and wherein the dearomatised roast and ground coffee is a dearomatised slurry.

6: The method according to claim 5, wherein step (iii) comprises: (A) passing the deaeromatised slurry to a first filtration device at a temperature of from 90 to 150° C. to form a first coffee extract and a first filter cake; (B) adding water to the first filter cake to form a reconstituted slurry having at least 12 wt % coffee solids; (C) thermally treating the reconstituted slurry at a temperature of from 150 to 205° C.; (D) then passing the thermally-treated reconstituted slurry to a second filtration device to form a second coffee extract and a second filter cake; (E) combining the first and second coffee extracts to form a third coffee extract; and (F) concentrating the third coffee extract to form the intermediate coffee extract.

7: The method according to claim 6, wherein the water in step (ii) and/or step (B) is at a temperature of from 80 to 100° C.

8: The method according to claim 6, wherein the reconstituted slurry formed in step (B) has 12 to 30 wt % solids.

9: The method according to claim 6, wherein the second filter cake is subjected to a further high temperature extraction process to obtain a further coffee extract to be combined in step (E) with the first and second coffee extracts to form the third coffee extract.

10: The method according to claim 1, wherein the method further comprises packaging the coffee-extract product.

11: The method according to claim 1, wherein the method is a continuous process.

12: A spray-dried coffee powder for forming a coffee beverage, wherein the powder comprises particles comprising soluble coffee solids and insoluble coffee solids, the insoluble coffee solids comprising coffee oils and an insoluble coffee sediment fraction which is the non-oil portion of the insoluble coffee solids, wherein the powder comprises at least 6 wt % of the insoluble coffee sediment fraction, the insoluble coffee sediment fraction comprising, when analysed after acid hydrolysis, 1 wt % or less arabinose, wherein the powder comprises at least 0.8 wt % coffee oils by dry weight, and wherein the particles exhibit less than 20 wt % surface coffee oil, based on the total weight of coffee oils.

13: The spray-dried coffee powder according to claim 12, wherein when the powder is reconstituted in water it has a particle size distribution of oil droplets having a D50 oil droplet size of less than 7 microns, preferably 1 to 5 microns, and more preferably 2 to 4 microns.

14: The instant coffee composition according to claim 12, wherein the composition comprises from 7.5 to 15 wt % of the insoluble coffee sediment fraction.

15: The instant coffee composition according to claim 12, wherein the insoluble coffee sediment fraction comprises, when analysed after acid hydrolysis, from 0.5 to 1 wt % arabinose.

16: The instant coffee composition according to claim 12, wherein the powder comprises from 1 to 5 wt % coffee oils by dry weight and/or wherein the particles exhibit less than 15 wt % surface coffee oil, preferably less than 10 wt % surface coffee oil, based on the total weight of coffee oils.

17: The spray-dried coffee powder according to claim 12 obtainable by a) providing an aqueous coffee extract comprising from 30 to 55 wt % soluble coffee solids and from 1 to 10 wt % oil, wherein the aqueous coffee extract consists of water and coffee-derived components; b) subjecting the aqueous coffee extract to a two stage homogenisation process, wherein the first stage is conducted at 200 to 1000 Bar and the second stage is conducted at 10 to 100 Bar, to provide a homogenised coffee extract; c) spray-drying the homogenised coffee extract.

Description

[0165] The invention will now be described further with respect to the figures, in which:

[0166] FIG. 1 shows a flow-chart of the steps of the present invention.

[0167] As shown in FIG. 1, the method for the manufacture of a coffee-extract product includes a number of steps.

[0168] In step (a) roast and ground coffee 2 is provided having a mean particle size of from 100 to 600 microns, preferably 200 to 600 microns. Within this range, larger sizes are favoured for liquid extract products, whereas smaller sizes are favoured for dried soluble coffee products.

[0169] In step (b) the roast and ground coffee is mixed with water 5 to form a first slurry 10 containing 15 to 30 wt % coffee solids. The water 5 is added at a temperature of from 80 to 100° C., and preferably from 90 to 95° C. The solids level is determined by the particle size, since a minimum amount of water 5 is used as necessary to obtain a pumpable slurry 10. The larger the particle size, the more water 5 is required (the lower the solids) to achieve a pumpable slurry 10.

[0170] In step (c) the first slurry 10 is passed through an aroma-separation step to recover a coffee aroma fraction 15 and to form a deaeromatised slurry 20. A typical approach to this method involves the addition of steam 21 to the pumpable slurry 10 where the vapours are treated in a spinning cone treatment unit. The recovered aroma fraction 15 is about 10 wt % of the first slurry 10, such that the deaeromatised slurry 20 is 90 wt % of the slurry 10.

[0171] In step (d) the deaeromatised slurry 20 is passed to a first filtration device at a temperature of from 90 to 150° C., such as 90 to 100° C., to form a first coffee extract 25 and a first filter cake 30. The temperature is retained from the preceding step or can be further increased to increase the extraction yield. The filter cake 30 may be washed and is pressed to obtain the largest possible amount of soluble coffee solids.

[0172] In step (e) water 5 is added to the first filter cake 30 to form a reconstituted slurry 35 having at least 12 wt % coffee solids. The water 5 is preferably hot and there may be mechanical agitation to break up the first filter cake 30. The amount of water required to reconstitute a slurry tends to be higher than that required in step (b).

[0173] In step (f) the reconstituted slurry 35 is thermally treated at a temperature of from 150 to 205° C., such as 180 to 205° C. to form a thermally-treated reconstituted slurry 40. That is, it is pumped through a heat-treatment unit, such as a plug-flow reactor. Residence times in the heat treatment are typically at least 5 minutes to ensure good extraction.

[0174] In step (g) the thermally-treated reconstituted slurry 40 is passed to a second filtration device to form a second coffee extract 45 and a second filter cake 50. The second filter cake 50 may be washed and is pressed to obtain the largest possible amount of soluble coffee solids. The temperature in this step may be retained from the preceding step, or may be lowered as heat is recovered for use in step (b), such as down to a temperature of from 80 to 100° C.

[0175] The second filter cake 50 may then be burned in step M to produce heat for the process, or may be subjected to a further high temperature extraction step M to obtain a further coffee extract 52.

[0176] In step (h) the first coffee extract 25 and the second coffee extract 45 are combined to form a third coffee extract 55. Other aqueous coffee extracts may also be added in this step, such as further coffee extract 52.

[0177] In step (i) the third coffee extract 55 is concentrated to form a fourth coffee extract 60 having 35 to 70 wt % coffee solids, such as 35 to 60 wt % coffee solids.

[0178] In step (j) the coffee aroma fraction 15 is added to the fourth coffee extract 60 (intermediate coffee extract) to form an aromatised coffee-extract 65. The aroma fraction 15 is added in an amount of one part, relative to five parts of the fourth coffee extract 60.

[0179] The aromatised coffee-extract 65 is homogenised in step k in a two-step homogeniser 70 to form a homogenised coffee extract 75. The two-step homogeniser 70 performs a first step at a pressure of 700 Bar and a second step at 50 Bar.

[0180] The homogenised coffee extract 75 is spray dried in step (L) to form a dried coffee product 80.

[0181] The present invention will now be described further in relation to the following non-limiting examples.

EXAMPLE 1

[0182] Roast whole beans were ground to between 200 μm and 400 μm in a 3 stage roller grinder.

[0183] The roast and ground coffee was slurried with water at 20° C.-30° C. at a ratio of 25% Coffee to 75% water.

[0184] The slurry was fed forward into a heat exchanger and heated to 95° C. before moving into a spinning cone column where aroma was stripped from the slurry.

[0185] Upon exit of the spinning cone the slurry was fed forward through a heat exchanger, raising the temperature to between 120° C. and 150° C. for 2 to 5 minutes.

[0186] The slurry was then fed into a filter separating the coffee liquor from the grounds. The grounds were then subjected to 2 further washing steps at 130° C. to 150° C. to remove additional solids.

[0187] The grounds were then re-slurried at a ratio of 12% to 17% solids with fresh water. The resulting slurry was fed forward to a hydrolysis step where it was heated to between 180° C. and 205° C. (185° C.) and held for between 5 and 20 minutes.

[0188] The resulting slurry was then cooled to below 100° C. before passing through a second filtering step repeating the separation and washing of the first separation step.

[0189] The coffee extracts obtained from each filtration step were combined and concentrated. The aroma compounds stripped from the first slurry where then added to the mixture.

[0190] The fully combined three components were then subjected to homogenisation at 200 Bar and then 40 Bar. The homogenised extract was spray-dried with a conventional process to obtain a soluble coffee powder.

EXAMPLE 2

[0191] Arabica and/or Robusta beans were roasted and ground, using a 3-stage roller grinder, to a mean particle size of 300 um. The ground coffee was then slurried with water at 20-25° C. at a ratio of 25% coffee to 75% water.

[0192] The slurry was fed forward into a heat exchanger and heated to 70° C. before moving into a spinning cone column where aroma was stripped from the slurry.

[0193] The slurry was then fed into a filter at a temperature of 95° C. separating the coffee liquor from the grounds. The grounds were then subjected to 2 further washing steps to remove additional solids.

[0194] The grounds were then re-slurried at a ratio of 12% to 17% solids with fresh water. The resulting slurry was fed forward to a plug-flow reactor (hydrolysis step) where it was heated to 170° C. and held for 5-10 minutes.

[0195] The resulting slurry was then cooled to below 100° C. before passing through a second filtering step repeating the separation and washing of the first separation step.

[0196] The coffee extracts obtained from each filtration step were combined and concentrated. The aroma compounds stripped from the first slurry where then added to the mixture.

[0197] The fully combined three components were then subjected to homogenisation at 200 Bar and then 40 Bar. The homogenised extract was spray-dried with a conventional process to obtain a soluble coffee powder.

[0198] The product of this example was found to have more body/mouthfeel than products produced using current technology.

EXAMPLE 3

[0199] A coffee slurry was prepared as described in Example 1.

[0200] The slurry was fed forward into a heat exchanger and heated to 95° C. before moving into a spinning cone column where aroma was stripped from the slurry.

[0201] Upon exit of the spinning cone the slurry was fed forward through a heat exchanger, raising the temperature to between 145-150° C. for 4 to 5 minutes.

[0202] The slurry was then fed into a filter separating the coffee liquor from the grounds. The grounds were then subjected to 2 further washing steps at 140° C. to remove additional solids.

[0203] The slurry was then fed into a filter separating the coffee liquor from the grounds.

[0204] The grounds were then re-slurried at a ratio of 12% to 17% solids with fresh water. The resulting slurry was fed forward to a plug-flow reactor (hydrolysis step) where it was heated to 200° C. and held for 7-10 minutes.

[0205] The resulting slurry was then cooled to below 100° C. before passing through a second filtering step repeating the separation and washing of the first separation step.

[0206] The coffee extracts obtained from each filtration step were combined and concentrated. The aroma compounds stripped from the first slurry where then added to the mixture.

[0207] The fully combined three components were then subjected to homogenisation at 200 Bar and then 40 Bar. The homogenised extract was spray-dried with a conventional process to obtain a soluble coffee powder.

[0208] The product of this example was found to have more body/mouthfeel than products produced using current technology.

EXAMPLE 4

[0209] Arabica and/or Robusta beans were roasted and ground, using a 3-stage roller grinder, to a mean particle size of 400 um. The ground coffee was then slurried with water at 20-25° C. at a ratio of 15% coffee to 85% water.

[0210] The remainder of the process was conducted as per example 1.

[0211] The resulting product has lower levels of oil than the product of example 1.

Oil Droplet Assessment

[0212] The size of oil droplets in a coffee extract produced according to the method in P1 (see Example 1) was investigated before and after homogenisation at different stage 1 pressures. Stage 2 was at 40 Bar in each case. The time period indicates the stability after the homogenisation.

[0213] As shown in the data, the higher pressure gives a greater oil droplet stability over time. Also, the higher pressure gives a smaller D50 size and a narrower distribution range (D90-D10). The concentration of the extract also has an effect on the size and stability. The weak concentrate was only 10 wt % solids, whereas the concentrated extract was at 50 wt % solids.

[0214] This demonstrates that for a non-homogenised high oil-extract the D50 value is around 9.6 microns, whereas for a homogenised high oil extract the D50 is much lower at around 3.2 and 2.9. It is noted that the weak extract data falls outside the range of solids claimed and has too much water for spray-drying, but still supports the same trend.

TABLE-US-00001 Weak Extract Number of Dv10 Dv50 Dv90 Sample Timepoint droplets counted (μm) (μm) (μm) Unhomogenised 0 920 3.0 6.0 8.0 Homogenised at 200 0 4704 1.0 2.0 3.0 bar 180 mins 3380 1.0 2.0 3.0  1 week 555 4.5 12.0 18.0 Homogenised at 500 0 1699 0.5 1.5 2.3 bar 180 mins 3429 1.0 1.8 2.8  1 week 1743 2.0 5.0 8.0

TABLE-US-00002 Concentrated Extract Number of Dv10 Dv50 Dv90 Sample Timepoint droplets counted (μm) (μm) (μm) Unhomogenised 0 1389 5.6 9.6 12.6 Homogenised at 200 0 5524 1.9 3.2 4.6 bar 180 mins 6085 2.1 3.4 4.6  1 week 3832 2.1 3.4 4.7 Homogenised at 500 0 6824 1.7 2.9 4.0 bar 180 mins 7014 1.8 3.0 4.2  1 week 4944 1.8 2.9 4.0

FURTHER EXAMPLES

[0215] The following examples were performed with the method of PCT/EP2019/086859 (hereafter P1) and are provided at least as comparative evidence of the properties of prior art compositions.

[0216] Samples obtained by the method described herein were assessed in comparison to a range of commercially available soluble coffee products. As can be seen from the comprehensive testing, the products obtained by the process are new and can be readily distinguished from products obtained from conventional processes.

Oil Content

[0217]

TABLE-US-00003 Sample Type Bean blend* Fat Content 1 Alta Rica ™ Pure Instant Arabica 0.3 2 Nescafe Gold Whole Bean Arabica/Robusta 0.4 Blend ™ Instant 3 Kenco Really Pure Instant Arabica/Robusta 0.2 Rich ™ 4 Milicano ™ Whole bean Arabica/Robusta 0.7 Instant 5 Percol ™ Pure Instant Robusta 0 6 Kenco Really Pure Instant Arabica/Robusta 0.2 Rich ™ 7 Prototype P1 Arabica 1.8 Colombian 8 Prototype Central P1 Arabica 1.8 9 Prototype P1 Robusta 0.4 Robusta 10 Prototype Brazil P1 Arabica 3.9 *bean identity for competitor products is based on an educated guess

[0218] Examples 7, 8, 9 and 10 have been produced in accordance with the method described in P1. Examples 1-6 are commercially available products, of which 2 and 4 are products supplemented with added roast and ground coffee additives (designated “whole bean instant” in the table).

[0219] It should generally be appreciated that levels of oil in Robusta beans are lower than in Arabica beans. This is reflected with the generally lower levels of oil in products comprising Robusta beans, include inventive example 9. Sample 10 is a dark Brazil known for high oil levels.

[0220] As can be seen, there are low levels of oil in the pure instant coffees, i.e. samples 1, 3, 5 and 6, which have not been supplemented with roast and ground coffee additives. The oil levels are slightly higher in samples 2 and 4 due to the oil content of the roast and ground coffee additives, with sample 2 containing approximately 5% roast and ground coffee and Sample 4 containing more roast and ground coffee.

[0221] Samples 7, 8 and 10 contain high levels of oil due to the fine grind of roasted coffee in the process which releases more oil into the extract.

[0222] As can be seen, no conventional soluble coffee products contain significant levels of oil. Indeed, it is speculated that the levels of oil observed for some of these products is added afterwards to the surface of the dried powder to improve its aroma.

[0223] The only prior art products which contain high oil levels are a consequence of the addition of roast and ground coffee additives in the product. In contrast, the method described in P1 achieves high levels of oil, even for Robusta bean products.

Sediment Levels

[0224] Sediment levels were determined by taking 30 grams of a given coffee sample added to 70 grams of boiling water and shaken for 2 minutes. The sample is then centrifuged for 15 minutes at 10,000 g. After centrifugation the supernatant is decanted off and the sediment re-dissolved with 70 grams of boiling water, shaken for 2 minutes and then centrifuged again under the same conditions as above. This washing process is repeated 3 times for a total of four centrifugation steps. The sediment from the final wash is then freeze dried and then the sediment percentage is related to the starting sample of 30 g (e.g. 1.8 g of sediment represents a 6 wt % insoluble coffee sediment fraction).

TABLE-US-00004 Sediment Sample (wt %) 1 l'Or Intense ™ 5.2 2 Kenco Rich ™ 4.7 3 Carte Noir ™ 3.8 4 Kenco Milicano Americano ™ 11.5 5 Nescafé Gold ™ 4.4 6 Nescafé Azera Americano ™ 9.3 7 P1 Robusta 11.9 8 P1 Colombia Arabica 7.8 9 P1 Centrals Arabica 9.2

[0225] Examples 7, 8 and 9 have been produced in accordance with the method described in P1. Examples 1-6 are commercially available products, of which 4, 5 and 6 are products supplemented with added roast and ground coffee additives.

[0226] As can be seen, all commercially available instant coffee products have some level of insoluble coffee sediment fraction. This is expected to be small fragments of coffee cell walls which pass through the extraction system into the coffee extracts. The levels of the insoluble coffee sediment fraction typically increase for those products supplemented with added roast and ground coffee additives.

[0227] As can be seen, the products produced according to the method described in P1 all have significantly higher levels of insoluble coffee sediment fraction than instant coffee products which have not been supplemented with added roast and ground coffee additives.

Particle Size Distribution

[0228]

TABLE-US-00005 D D Dx Dx Dx [3, 2] [4, 3] (10) (50) (90) sample description μm μm μm μm μm 1 l'Or Intense ™ 1.84 15.7 0.79 2.85 8.49 2 Kenco Rich ™ 2.74 42.3 1.35 3.69 11.2 3 Carte Noir ™ 1.96 4.73 0.897 2.79 8.63 4 Kenco Milicano 4.32 13.1 1.6 11.7 27.3 Americano ™ 5 Nescafé Gold ™ 3.4 42.5 1.1 20.1 102 6 Nescafé Azera 5.91 136 2.16 31.1 197 Americano ™ 7 P1 Robusta 3.35 8.22 1.56 4.97 14.6 8 P1 Colombia Arabica 2.58 33.9 1.02 4.68 37.2 9 P1 Centrals Arabica 2.67 33.4 1.03 5.32 34.5

[0229] Examples 7, 8 and 9 have been produced in accordance with the method described in P1. Examples 1-6 are commercially available products, of which 4, 5 and 6 are products supplemented with added roast and ground coffee additives.

[0230] The sediment quantification method with multiple centrifugation steps allows for a large amount of very fine particles to be recovered.

[0231] Particle size distribution has been measured with the Malvern 3000 after making a 1.5% hot brew of the dried product, for example 3 g of dried product in 200 ml of hot water.

[0232] 3 classes of sediment can be distinguished:

Class 1 L'Or Intense™, Kenco Rich™ and Carte Noir™:

[0233] Unimodal distribution D10: <1.5 and D90: <15 μm

[0234] Relative low amount of sediment <5.5% wt

[0235] The very small particle size (such as low D90) perhaps reflects the way in which these particles have escaped from the extraction column into the extract, or mannans which have sedimented in the evaporator.

Class 2: Kenco Milicano™, Nescafé Gold™ and Azera™ Clearly Differs from Class 1 and 3

[0236] Bi-modal distribution (2 peaks) peak 1 between 1 and 10 μm and peak 2 between 10 and 100 μm.

Class 3: Inventive Samples

[0237] Unimodal distribution but broader distribution than class 1 D10: >1.0 and D90: >15 μm and relative higher amount of sediment such as >7.5% wt.

Carbohydrate Analysis

[0238] The analysis is of mono-saccharides after acid hydrolysis.

TABLE-US-00006 sample description Arabinose Galactose Glucose mannose Total 1 l'Or Intense ™ 0.71 3.45 0.33 61.2 65.7 2 Kenco Rich ™ 0.48 2.43 0.31 50.9 54.1 3 Carte Noir ™ 0.61 3.01 0.43 69.0 73.1 4 Kenco Milicano 1.99 8.88 0.4 36.1 47.4 Americano ™ 5 Nescafé Gold ™ 1.34 6.36 0.37 50.7 58.8 6 Nescafé Azera 1.42 7.06 0.46 60.8 69.7 Americano ™ 7 P1 Robusta 0.77 2.47 0.28 42.4 45.9 8 P1 Colombia 0.74 3.08 0.41 54.5 58.7 Arabica 9 P1 Centrals 0.76 3.51 0.45 55.2 59.9 Arabica

[0239] Examples 7, 8 and 9 have been produced in accordance with the method described in P1. Examples 1-6 are commercially available products, of which 4, 5 and 6 are products supplemented with added roast and ground coffee additives.

[0240] As can be seen, the insoluble coffee sediment fraction of the products of P1 has a level of Arabinose broadly similar to that of a soluble coffee product which has not been supplemented with roast and ground coffee. Typically it also has a lower level of galactose than a soluble coffee product which has been supplemented with roast and ground coffee

[0241] Without wishing to be bound by theory, it is considered that the high levels of arabinose in the supplemented products is a consequence of the presence of the unextracted coffee material. In contrast, for the products of P1, the levels are lower reflecting the fact that the arabinose has already been extracted into the soluble coffee fraction by the process of P1.

Sensory Testing

[0242] 2 prototypes of the product of P1 were combined with product from current technology in a ratio of 30 (POI):70 (current product). These were then tested in a set with an additional sample of 100% current technology product. The 3 samples were given to a panel of sensory experts who were then asked to pair the products according to similarities/dissimilarities to the third.

[0243] The results indicate that even at levels of only 30% in a blend with current products the prototype is considered more viscous/dry and powdery—all attributes contributing to mouthfeel/body. The levels correlate directly with the tribology data. More oil means more lubrication which means more mouthfeel/body. The effects are shown in FIG. 3.

Collapse Temperature

[0244] Crystalline products have a well-defined “eutectic” freezing/melting point, this point is called its collapse temperature. When freeze-drying a concentrated coffee extract, the extract is heated up from an initial frozen temperature of about −50° C. under a vacuum. This allows the water content to sublime away. The rate of heating depends on the extract and there is a collapse temperature above which the product will have melt-back and be compromised. The temperature and pressure can then be raised on subsequent cycles until evidence of collapse or melt-back is seen, indicating that the product was too warm. Surprisingly the inventors found that the collapse temperature for several samples of P1 were higher than that for their standard coffee products.

Rheological Behaviour of Samples

[0245]

TABLE-US-00007 1 Alta Rica ™ 2 Nescafe Gold Blend ™ 3 Kenco Really Rich ™ 4 Milicano ™ 5 Percol ™ 6 Kenco Really Rich ™ 7 NGC Colombian P1 8 NGC Central P1 9 NGC Robusta P1 10 NGC Brazil P1

[0246] Samples were prepared with 10 g of coffee dissolved in 40 g of water at 85° C. Full dissolution was achieved with 2 minutes stirring with a 25 mm stirring bar at 150 rpm.

[0247] These samples were tested with simple shear sweeps between shear rates of 0.01-1000 s.sup.−1 using a Discovery HR-2 Rheometer, sample volume 8 ml, with the circulation bath set to minus 4° C. The samples were studied at temperatures of 20 and 65° C. and at concentrations of 1.5 and 20 wt %.

[0248] The data has then been fitted to the Quemada model which develops insights into fluid rheology based on the theory of internal structural units (SUs) suspensions.

[0249] Within concentrated systems the single particles and small flocs may form increasingly larger groups the size of which will be dependent on the shear rates applied.

[0250] Therefore since viscosity (η) is a function of structure (η=f(s)). And the structure is dependent on the levels of shear applied (as increased shear rates will merely act to disperse the macro and meso-structures of the flocs into the individual sub-units), the viscosity can be expressed in terms of the packing fraction/compactness since the more compact the SU's the higher the packing and therefore the more structure (viscosity) there will be.

[0251] This is because the compactness of the SU's will contribute to the level of structure;

[00001]${\eta }_{\infty }={{\eta }_F\left(1-\frac{\varphi }{{\varphi }_{\infty }}\right)}^{-2}$${\eta }_0={{\eta }_F\left(1-\frac{\varphi }{{\varphi }_0}\right)}^{-2}$

[0252] Where η is viscosity and ϕ is the measure of compactness.

[0253] It was noted that at 20 wt % (i.e. concentrated samples) at 65° C. (close to temperature of consumption) that samples 4 (Milicano) and 7-10 have significantly higher η.sub.0. This means that from a microstructural perspective at lower shear rates (1 s.sup.−1) which are representative of those during mastication and are reflective of mouthfeel, these samples have more structure relative to the other samples. This implies that at these lower shear rates the compactness of their structural units is higher i.e. better packing of the structural units.

[0254] Tribology of the samples was also observed. “Tribology is the science and engineering of interacting surfaces in relative motion. It includes the study and application of the principles of friction, lubrication and wear.” Therefore the parameter to pay attention to is the μ.sub.max which represents the maximum friction observed for each sample. Since lubrication is indicative of mouthfeel here and a higher μ.sub.max indicates lower rates of lubrication which should translate to lower mouthfeel.

[0255] It was observed that at 65° C. (consumption temp) samples 7, 8 and 10 have significantly lower values for μ.sub.max indicating lower friction and hence higher mouthfeel. The exception is sample 9 (Robusta blend) with lower oil content.

Measuring the Surface Oil Content of a Soluble Coffee Powder

[0256] The sample is extracted by Soxhlet extraction, and the oil content weighed out.

Equipment

[0257] Soxtherm Gerhardt extraction unit

[0258] Multistat Soxterm service unit

[0259] Air oven/circulating oven @ 105° C.±2° C.

[0260] Analytical balance

[0261] Desiccator with silica gel

Materials and Consumables

[0262] Gerhardt extraction beaker G_Nr. 13-0050

[0263] Coffee filters (no 4)

[0264] Extraction thimbles, 33×80 mm (S&S 603)

[0265] Cotton wool

Reagents

[0266] Hexane 40-60° C. boiling range, AR grade (also known as Hexane)

Sample Analysis

[0267] Place extraction beaker in the drying oven for 1 hour at 103° C. [0268] Remove from oven and allow to cool in the desiccator. [0269] Weigh the extraction beaker to 4 decimal places (M1). [0270] Weigh 5-gram dried sample (M2) into a coffee filter paper No 4 and fold it together put the filter in the thimble leaving 5 mm space to place a cotton wool plug on top. [0271] Carefully place a cotton wool plug on top. [0272] Place the extraction thimble into the weighed extraction beaker [0273] Fill the extraction beaker with 150 mL n-hexane [0274] Place the extraction beaker with content in the device Soxtherm [0275] Extract it with the aid of the Multi-Stat Program Base Unit (15 mi extracting boiling, 30 minutes (Total analysis time is 1 hour and 17 min). [0276] After the extraction, move the extraction thimble. [0277] The residual hexane in the extraction beaker gently blown out with compressed air, and further evaporated in the oven for 1 hour at 105° C. [0278] After cooling, weigh extraction beaker with the oil obtained (M3)

Expression of Results

[0279] [00002]$\mathrm{Oil}\left[\%\mathrm{odb}\right]=\frac{\mathrm{Weight}\mathrm{of}\mathrm{Oil}\left(M3-M1\right)}{S\mathrm{ample}\mathrm{weight}\left(M2\right)}\times 100$

[0280] Unless otherwise stated, all percentages herein are by weight.

[0281] Although preferred embodiments of the invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the scope of the invention or of the appended claims.