IE49220B1 - Method for aromatizing coffee products - Google Patents

Description

The present invention pertains to aromatized particles of coffee products.

Soluble beverage powders such as spraydried coffee products are relatively devoid of aroma as compared to their source or parent materialnamely, roasted and ground coffee. Low aroma intensity also exists in certain types of roasted coffee material such as most decaffeinated coffees and the compressed roasted coffee materials des10 cribed in U.S. Patents Nos. 1,903,362 to McKinnis, 3,615,667 to Joffe and 3,801,716 to Mahlmann et al. These low-aroma beverage products have an initially low quantity of aroma, such that upon the initial opening of the product by the consumer only low aroma impact is detected, and whatever amount of aroma is present in the product is rapidly given up after initial opening of the container, such that 48220 subsequent openings of the container during a typical in-use cycle for the product evolve little or no aroina.

It should be noted that the term coffee product as used in this invention is meant to refer to not only those materials consisting of 100% coffee but also to substitute or extended coffees which may contain roasted grain (e.g. wheat), chicory or other vegetable material either alone or in combination with coffee.

To date most efforts to add natural aroma to coffee products have focused on the addition of roasted coffee aroma to soluble coffees such as spray- or freeze-dried coffee. Understandably then the thrust of the present invention is in the area of aromatizing coffee products.

At the present time, virtually all commercial soluble coffees are combined with coffee oil such as by spraying the soluble coffee prior to packaging with either a pure or an aroma-enriched coffee oil.

In this manner the soluble coffee material will have an aroma more akin to non-decaffeinated roasted and ground coffee. The addition of oil is usually effected by the well-known oil plating technique (shown in U.S. Patent No. 3,148,070 to Mishkin et al.) or by oil injection (shown in U.S. Patent No. 3,769,032 to Lubsen et al.). At the present time, commercial roasted coffee products do not contain any added aroma, all attempts at producing a more aromatic product being directed to preserving the aromatics contained within the freshly roasted coffee beans.

Coffee oil with or without added aromas has been the preferred medium employed to aromatize coffee material since such products could still be designated as being pure coffee; however, techniques developed for the production of coffee oil (see Sivetz, Coffee Processing Technology, Vol. 2, Avi Publishing Company, 1963 pages 21 to 30) such as solventextracting or expelling coffee oil from roasted coffee are not particularly desirable since the manufacturer is left with either solvent-containing roasted coffee or expelled cake, both of which must be either further processed or discarded. The addition of oil to a coffee product has also proven troublesome in that, undesirably, oil droplets can appear on the surface of the liquid beverage prepared from the oil-containing product. Thus, it would be advantageous if processes for aromatizing coffee products were developed which employed all coffee or other vegetable materials, but which did not require the production or addition of coffee oil or other glyceride material.

According to the present invention there is provided an aromatized dry coffee product as herein defined comprising a blend of a lcwaroma vegetable material and particles of aroma-loaded vegetable material, the vegetable material of said particles being selected from roasted coffee, roasted grain, roasted chicory and combinations thereof, said particles having a diameter below 200 microns, having a natural oil content of at least 1% by weight and being present in an amount of from 0.05% to 10% by weight of the coffee material, said vegetable material having an essentially insoluble cellular structure as hereinafter defined and said particles having adsorbed therein an amount of volatile aromatic coffee compounds in excess of 0.2% by weight of said particles and sufficient to provide a pleasant headspace aroma to the dry coffee product. There is also provided a method for providing a headspace aroma for a dry, packaged low-arena coffee product as herein defined ccnprising 4832ο the steps of: a) contacting particles of vegetable material having a diameter below 200 microns selected from roasted coffee, roasted grain, roasted chicory and combinations thereof with volatile aromatic coffee compounds such that aromatics in an amount in excess of 0.2% by weight of the resulting particles are adsorbed by the particles, said vegetable material having an essentially insoluble cellular structure and a natural oil content of at least 1% by weight. b) combining the aromatized particles of step (a) with a dry, low-aroma vegetable material at a level of 0.5% to 10% by weight. c) packing the combination of step (b) in a sealed container.

Particles of vegetable material having an essentially insoluble cellular structure (i.e. insoluble in common solvents including water) and a natural oil content of at least 1% and preferably at least 3% by weight, such as coffee, grain (e.g. wheat) or chicory material and which particles may be in the form of roasted whole coffee beans or subdivided particles of roasted coffee, wheat or chicory including ground or colloidally milled particles are employed as the carrier for coffee aroma. The particles could be obtained from compressed roasted coffee or even spent roasted 49230 coffee grounds, such as the waste grounds from soluble coffee manufacture. These particles are contacted with volatile aromatic compounds such that the aromatics are entrapped or adsorbed in an amount in excess of 0.1% by weight. Although it would be theoretically possible to adsorb aromatics in an amount up to about 5% by weight, in actual practice levels in excess of 1% are difficult to achieve. Conventional roasted and ground coffee material to which no aromatics have been added contain aromatics in an amount below 0.05% by weight. The aromatized particles of this invention will contain aromatics at a level of 0.2% or more, typically about 0.5%. This aromatized roasted material is combined with low-aroma coffee products at an appropriate weight level in order to provide a desirable aroma. A level of about 0.05% to 2% of added particles is used when the insoluble or only partially soluble particles are combined with a soluble powder in order to limit the amount of sediment in the reconstituted product. An aromatic level within the particle of only 0.1% by weight would typically require the addition of more then 5% of these particles to the low-aroma coffee product.

When the aromatized particles are combined with an insoluble material, it would of course be possible to employ a higher level, say up to 10% by weight.

When it is desired to obtain particles smaller than 200 microns cryopulverization techniques such as that disclosed in U.S. Patent No. 3,965,267 to Davis have proven quite useful. Conventional soluble coffee material, such as spray-dried or freeze-dried coffee has not proven to be a useful 49230 carrier when employed in the process of this invention. Soluble coffee powder has not been found to either adsorb, retain or stabilize aromatics to the same extent or in the same manner as the roasted coffee, grain or chicory materials which are employed in this invention.

The method of contacting the roasted particles with aromatics for the purpose of entrapping aroma within the particles can be many and varied. The use of high pressure and/or low particle temperatures may be employed in order to maximize pick-up of aroma or shorten the period of time required to achieve a desired level of aromatization; however, such conditions are not required. It will usually be desirable, however, to minimize the amount of moisture which comes into contact with the particles both before, during and after aromatization. The moisture content of and amount of the material supplying aromatics to the roasted particles should be controlled so that the moisture content of the particles is kept below about 15% by weight. Suitable condensation, vaporization, sweeping and/or other separation techniques may be employed to separate moisture and aromatics contained in aromabearing gas streams, aroma frosts or liquid aromatic condensates. It may also be desirable to separate aromatics from any carrier gas (e.g. CC^) in which they are entrained. Among the techniques useful for adsorbing aromatics into the roasted particles are: (1) placing a mixture of the roasted particles and a condensed C02 aroma frost in a vented vessel, preferably above -40°C, and permitting the CO2 portion of the frost to sublime off, (2) enclosing both the roasted particles and a condensed aroma frost in one or two connected pressure vessels and then raising the temperature within the frost containing vessel to vaporize the frost and provide an elevated pressure, (3) combining a highly concentrated agueous aroma condensate with the roasted particles at a level at which it does not unduly moisten the particles, (4) condensing aromatics onto chilled roasted particles, (5) passing a stream of aroma-bearing, low-moisture gas through a bed or column of roasted particles.

The aromatics which may be used for this invention may be derived from any of the many sources well-known to those skilled in the art. Depending on the method of contact to be employed, the aromas may be present as a component of a gas, a liquid condensate or a condensed frost. Among the aromas which may be used are coffee oil aromas, as described in U.S. Patent No. 2,947,634 to Feldman et al., aromas obtained during the roasting of green coffee, as described in U.S. Patent No. 2,156,212 to Wendt, aromas obtained during the grinding of roasted coffee, as described in U.S. Patent No. 3,021,218 to Clinton et al., steam-distilled volatile aromas obtained from roasted and ground coffee, as described in U.S. Patents Nos. 2,562,206 to Nutting, 3,132,947 to Mahlmann, 3,244,521 to Clinton et al., 3,421,901 to Mahlamnn et al., 3,532,507 to Cascione and 3,615,665 to White et al., and the vacuumdistilled aromas obtained from roasted and ground coffee, as described in U.S. Patents Nos. 2,680,687 to Lemonnier and 3,035,922 to Mook et al. It would, of course, also be possible to employ volatile synthetic chemical compounds which duplicate or simulate the aromatic compounds naturally present in roasted coffee. As will be recognized by those skilled in the art, the addition of volatile aromatic compounds to food products will, along with providing the desired aroma enhancement, also provide a flavor effect to the presence of an amount of these compounds in the food product at the time of consumption.

According to one embodiment of this invention, a coffee aroma gas containing a high carbon dioxide level, preferably above 80% by weight, is obtained from a source such as commercial coffee grinding equipment. This gas is preferably passed through a first condenser where it is cooled to between 2°C and 10°C and where most of the moisture contained in the gas is condensed. This gas is then fed to a condenser, such as a jacketed, scraped-wall heat exchanger, cooled by means of a liquid gas refrigerant such as liquid nitrogen, where the gas is condensed to the form of a carbon dioxide frost.

The frost is then placed in a pressure vessel where it is warmed, such as by means of a surrounding water jacket, to at least -29°C and preferably between about 2°C and 65°C. The amount of frost and the pressure vessel are sized so that a gaseous pressure of at least 6.8 atmospheres will be developed within the vessel or vessels. As the temperature of the frost increases above about -56.6°C, the solid carbon dioxide contained in the frost is converted to an aroma-bearing liquid phase and/or saturated vapor phase.

The aroma-bearing carbon dioxide vapor is then permitted to contact roasted coffee, wheat and/or chicory material, this contact taking place either in the same vessel in which the frost is vaporized or in a second vessel which is fed with the aroma-bearing carbon dioxide vapor. As will be apparent to those skilled in the art, when two or more vessels are employed, the total volume of all of the vessels and the connecting ducts will be inversely proportional to the pressure developed within the system.

After the desired period of contact, the vessel containing the low aromatized roasted adsorbent will be isolated if necessary and then cooled, usually to a temperature below 0°C and preferably below -45°C, before it is vented. This cooling step will cause additional coffee aromatics to be adsorbed by virtue of the adsorption power/ capacity of the adsorbent (i.e., capillary con15 densation with the microporous structure). It would, of course, be possible to maximize this additional adsorption by cooling to the point where a frost is reformed. At this point, the pressure within the vessel would approach atmospheric and it will usually be desirable to then heat and vent the vessel in order to remove carbon dioxide and raise the temperature of the contents above 0°C.

When separate vessels are used for the frost and the adsorbent material, it will be possible to recover a portion of the aromatics which might be vented from the adsorbent-containing vessel along with carbon dioxide. This can be effected by isolating the frost vessel and cooling it to recondense carbon dioxide to a frost. If this cooled frost vessel is then connected to the adsorbent vessel vent line, the vented vapors will pass to the frost vessel where they will be condensed and available for aromatizing additional roasted coffee, wheat and/or chicory material. η The specific particle size of the roasted coffee, wheat and/or chicory material to be aromatized according to this invention has not been found to be critical. The use to which the aroma-bearing particles will be put may dictate the size parameter. For instance, it may be desired (1) to aromatize whole coffee beans, a few of which could be incorporated into a container of roasted and ground or soluble coffee product giving a product with unique appearance, (2) to aromatize roasted coffee, wheat and/or chicory particles the size of which will match the roasted and ground product with which they are to be blended, and (3) to aromatize particles of a size 20 (U.S. Standard Screen) mesh (840 microns) or less for incorporation into a soluble coffee product. Finely ground roasted material having a particle size below 200 microns and preferably about 25 microns can be advantageously obtained following the cryopulverization technique of the aforementioned Davis patent. Colloidal sized particles can also be used.

The oil content of the roasted particles of at least 1%, preferably at least 3%, is believed to enhance the ability of the cellular particles to entrap aromatics. This enhancement may be evidenced by adsorption of a higher quantity of aromatics and/or a broader spectrum of aromatics. It has also been found that this oil component can also serve a useful purpose when an aromatized powdered food material produced in accordance with this invention is packaged in glass jars, since even minute amounts of oil contained within the packaged product will prevent small particles of material from adhering to the inside of the glass jar, thus producing a possible unsightly appearance.

The moisture content of the starting roasted coffee, wheat and/or chicory material should be below about 7% in order to avoid stability problems in the fixed aromatics, especially during the period before the aroma-bearing adsorbent is combined with the low-aroma coffee product. Once the combination is effected, excess moisture that may be present in the aroma-bearing adsorbent will migrate to the low-aroma product which has been previously dried to a stable moisture content. Since the aromatized adsorbent may be added at a level below about 2% by weight of the low aroma material, the total amount of moisture transferred may be insignificant.

This invention is further described but not limited by the following Examples.

Example 1 300 grams of roasted and ground coffee were placed in a CC^-flushed, 2-liter Parr Bomb. A second Parr Bomb containing 200 grams of grinder gas frost was placed in a 50°C water bath causing the frost to sublime and produce an internal temperature of about 24°C and a maximum pressure of about 62.2 atmospheres. Using a high pressure tube connection, the two Parr Bombs were then maintained at room temperature for three hours. The bomb containing the roasted and ground coffee was isolated and then cooled and maintained at about -70°C for 10 hours.

Thereafter this bomb was vented and warmed to 0°C.

The resulting aromatized roasted and ground coffee possessed an intense aroma of fresh roasted coffee.

Example 2 200 grams of grinder gas frost and 300 grams of regular grind roasted coffee (average particle size 860 microns) were placed and sealed in a 2-liter Parr Bomb under a CO2 atmosphere. Three layers of paper towels were placed between the frost and coffee as an adsorbent in order to pick up moisture from the frost component and minimize caking of the roasted coffee. The contents of the bomb were then warmed to room temperature (24°C) over three hours where a pressure of about 41.8 atmospheres was developed and these conditions were maintained for an additional hour. Using dry ice, the bomb was cooled for up to 20 hours until the internal pressure was reduced to atmospheric. Then, applying an ice bath, the Parr Bomb was warmed to 0°C and about 14.6 atmospheres; C02 was then slowly vented out of the system. Under a C02 atmosphere, the Parr Bomb was opened and the aromatized roasted coffee removed and combined with agglomorated spraydried coffee powder at a level of 0.58% by weight (1 gram per 6 oz. (170 gms) of powder) and sealed in a glass jar under a co2 atmosphere.

Example 3 The procedure of Example 2 was repeated using fine grind (average particle size 620 microns) roasted and ground coffee and whole beans in place of regular grind coffee. The sealed jars of each of these three variants were evaluated periodically, both organoleptically and with a carbon gas chromatograph (GC) and compared to a control sample aromatized by adding a grinder gas aroma-enriched (1.8:1 frost to oil ratio) coffee oil into a 6 ounce (170 grams) jar of agglomerated spray-dried coffee at a 0.2% level. The aromatized coffee oil was prepared in accordance with the high-pressure decanting technique of commonly-assigned U.S. Patent No. 4,119,736 to Howland et al. Thus, the quantity of grinder gas frost consumed in the preparation of all samples was at a comparable level (0.67 vs. 0.61 grams per jar). Table I summarizes the relative quantity of the total volatile hydrocarbon compounds present in 1 cc of the headspace in the sealed jars as a function of time at 35°C storage.

TABLE I °C Storage Stability of Aromatized Soluble Coffee Average GC Counts in Millions (±10%) Regular Grind Fine Grind Aroma Carrier Coffee Oil Control Roasted Whole Beans Roasted Coffee Roasted Coffee Storage Time (in wks. 1 0 1.75 1.10 4.30 2.00 2 1.81 1.15 3.60 2.20 4 1.75 1.13 - 1.80 6 1.60 1.00 3.10 1.90 S 1.50 1.15 3.10 2.00 10 1.40 1.20 3.10 Examination of Table X shows that soluble coffee aromatized with the different sized particles of aromatized roasted coffee held up very well in terms of headspace counts regardless of initial aroma level. Organoleptic evaluations confirm the above data.

In conjunction with GC measurements, periodic organoleptic evaluations were carried out on each sample by a panel of skilled coffee tasters. Briefly, a typical organoleptic evaluation consists of two segments. First, the oxygen content of the sealed jar is determined using a Beckman (Beckman is a Registered Trade Mark) Oxygen Analyzer, Model C2. The oxygen content should be under 4 percent. The seal of the jar is then broken and the relative quality, intensity and nature of the aroma in the headspace is recorded, by three to five experienced panelists, each with their own set of samples. The jars are then commonly ranked according to their relative intensities (impact) on a scale of 1 (nil) to 9 (very intense) and accord15 ing to their relative qualities on a scale of 1 (extremely poor) to 9 (excellent). The second phase of the evaluation involves the preparation of a brewed cup of the soluble coffee and a determination of each cup's relative “flash aroma and flavor. Finally, a visual inspection of each cup's surface appearance was made noting the presence of any oil, roasted coffee or other matter. In addition, for these samples, the cups were carefully decanted and the presence of sediment was noted. In general, a rough approximation indicated that 40 percent of the cups prepared with the regular grind sample had one to five specks on the surface and/or a perk-like sediment in the bottom of the cup. For the fine grind sample, about 30 to 40 percent of the prepared cups contained a light perk-like sediment after decanting the brew. The surfaces of all the variant samples were totally oil-free. The coffee oil control sample produced cups having noticeable surface oil. .. 49220 Table II and III relate the average opinions of the panelists for jar aroma impact and quality, respectively, as a function of storage time. TABLE II 5 Effect of 35°C Storage on Jar Aroma Impact Rating (Impact Ratinq on a Scale of 1 to 9) Time Coffee Whole Regular Fine (weeks) Oil Beans Grind Grind 0 7.5 6.5 6.5 7.0 10 2 6.0 5.0 6.0 6.5 4 5.5 4.5 6.0 6.0 6 5.7 5.0 6.0 6.0 8 6.0 5.0 6.0 5.5 10 6.0 6.0 6.0 15 TABLE III Effect of 35°C Storage on Jar Aroma Quality Rating (Quality Rating on a Scale of 1 to 9) Time Coffee Whole Regular Fine (weeks) Oil Beans Grind Grind 20 0 7.0 6.5 7.0 7.0 2 5.7 5.0 7.0 6.5 4 5.0 4.0 6.5 5.5 6 6.0 4.0 5.5 5.5 8 6.0 5.0 6.0 5.0 25 10 6.0 6.0 6.0 As can be seen from the foregoing results, the aroma impact and quality of the tested variants are comparable to the aromatized oil control. The gas chromatograph of the variants all showed a very 40220 similar headspace composition to that of the control.

After ten weeks of storage at 35°C, sealed jars were evaluated in an in-use test which reflects a simulation of actual consumer use day by day. The results of this study showed all three variants to possess comparable aroma impact and quality to the oil control.

Example 4 Spent coffee grounds were dried to 7% (by weight) moisture and 300 grams of the grounds were placed in a 2-liter Parr Bomb containing a bottom layer of 200 grams of grinder gas frost and a layer of paper toweling. The Bomb was then sealed, warmed to room temperature (about 59 atmospheres) and after 3 hours the Bomb was then cooled by dry ice to reduce the internal pressure to atmospheric. The Bomb was then inserted into an ice bath, warmed to 0°C and then vented. The aromatized spent grounds were then blended with soluble coffee powder at a level of 0.5%. After storage under inert conditions, the resulting product was characterized as having a pronounced and pleasant coffee-like aroma with slightly more green notes than the products of Examples 2 and 3.

Example 5 Dark roasted Colombian coffee beans are cryopulverized using liquid nitrogen as the cryogenic fluid. The ground particles possessed an average size of 125 microns and were kept under a dry atmosphere. Subsequently the particles were well mixed with coffee grinder gas frost at a weight ratio of 1.2:1. The mixture was then transferred to a prechilled, pinhole vented jar and stored at -8°C overnight. Thereafter the aromatized particles are combined with spray dried coffee agglomerate at a level of 0.2% by weight and packaged in glass jars under an inert atmosphere. Upon prolonged storage, the jars are found to contain a pleasant headspace aroma.

Claims (8)

1. CLAIMS:1. An aromatized dry coffee product as hereinbefore defined comprising a blend of a low-aroma vegetable material and particles of aroma-loaded vegetable material, the vegetable material of said particles being selected from roasted coffee, roasted grain, roasted chicory and combinations thereof, said particles having a diameter below 200 microns, having a natural oil content of at least 1% by weight and being present in an amount of from 0.05% to 10% by weight of the coffee material, said vegetable material having an essentially insoluble cellular structure as hereinbefore defined and said particles having adsorbed therein an amount of volatile aromatic coffee compounds in excess of 0.2% by weight of said particles.

2. A product according to claim 1 wherein the lowaroma vegetable material comprises coffee and the aromaloaded particles are present at from 0.05% to 2% by weight,

3. The product of claim 1, wherein the low-aroma vegetable material comprises roasted coffee.

4. The product of claim 3, wherein the roasted coffee is a decaffeinated coffee.

5. The product of claim 1, 2 or 3, wherein the vegetable material of said particles is roasted coffee, said particles having a coffee oil content of at least 3% by weight.

6. A method for providing a headspace aroma for a dry, packaged low-aroma coffee product as hereinbefore defined comprising the steps of: a) contacting particles of vegetable material 5 having a diameter below 200 microns selected from roasted coffee, roasted grain, roasted chicory and combinations thereof with volatile aromatic coffee compounds such that aromatics in an amount in excess of 0.2% by weight of the resulting particles are adsorbed by the particles, said 10 vegetable material having an essentially insoluble cellular structure as hereinbefore defined and a natural oil content of at least 1% by weight, b) combining the aromatized particles of step (a) with a dry, low-aroma vegetable material at a level of 15 0.05% to 10% by weight, c) packing the combination of step (b) in a sealed container.

7. An aromatized dry coffee product as claimed in claim 1 substantially as herein described with reference 20 to any of the Examples.

8. A method as claimed in claim 6 substantially as herein described with reference to any of the Examples.