AU2002236763A1 - Method of preparing coffee aromatizing compositions - Google Patents

Description

METHOD OF PREPARING COFFEE AROMATIZING COMPOSITIONS

Field of the Invention

The invention relates to methods of preparing coffee aromatizing cor positions.

In particular, the invention relates to methods of preparing such composite as v* '^^"ch

are useful to provide coffee beverage preparation aroma.

Background of the Invention

The manufacture of "instant" (or soluble) coffee powder, often involves

processing conditions such as elevated temperature, which cause loss of desirable

coffee aroma. By the time the powder is prepared, most of the chemicals that create

the distinctive pleasurable coffee aroma have evaporated. Unless additional steps are

taken during manufacture, there is very little aroma associated with hot coffee

beverages prepared f om instant coffee powder relative to the aroma of hot coffee

beverages prepared from roast and ground coffee. This, in large part, has contributed

to consumers viewing instant coffee as an inferior product. Many attempts have been

made to enhance the aroma of instant coffee, including the use of particular types of

coffee beans, the use of particular coffee roasting conditions, and the addition of

coffee aroma.

Coffee aromas and flavors are usually complex, comprising many

organoleptically active compounds, which combine in effect to create the

characterizing aroma of the product. Since the aromas and flavors are extremely

powerful and typically unstable in their undiluted state they are combined with a

/ carrier to render them stable and easier to handle. The carriers are neutral or

complementary in organoleptic impact and do not contribute to the characterizing

aroma of the product.

Aroma carriers can be liquids or water-soluble solids. In cases where a liquid

carrier is used, it is often encapsulated in a solid, water-soluble matrix to further

preserve the characterizing aromas from loss or damage. The carrier, often referred to

as a solvent in liquid systems, functions as an aroma base and is used to adjust the

level of otherwise powerful aroma and taste substances to levels similar to those that

exist in nature. Desirable characteristics of carriers for liquid systems include

blandness and miscibility with other liquid aromas. The traditional liquid carrier used

for coffee aromas, and the liquid carrier perhaps exclusively used for coffee aroma

frosts, is coffee oil that has been expelled from roasted coffee or extracted from spent

coffee grounds used in the manufacture of instant coffee.

The aroma constituent of an aromatizing composition characterizes its aroma,

i.e., the innate quality that gives the aroma its special attributes among and over other

aromas. The aroma constituent may, and often does, include a plurality of aroma

ingredients which together result in the characterizing aroma.

A particular problem that has been noted in connection with instant coffee is

the relative lack of coffee aroma that is generated at the time that a hot instant coffee

beverage is prepared compared to the coffee aroma that is generated when brewing

roasted and ground coffee. This problem of poor aroma burst or "above-cup aroma"

at the time of preparation of an instant coffee beverage is noted in U.S. Patent No.

5,399,368 assigned to Nestec S.A. and in U.S. Patent No. 5,750,178 also assigned to Nestec S.A. Each of these patents describes several prior art attempts to provide an

initial burst of above-cup coffee aroma, such as by coating soluble coffee powder with

an aqueous emulsion of an aromatic coffee substance, or by employing particulate

aromatized coffee glass. It is reported in each of these U.S. patents that these and

other previously known procedures were not successful in achieving a good above-

cup aroma. The '368 and ' 178 patents propose methods for making capsule particles

containing an aromatized coffee oil core.

The amount of above-cup aroma which can be achieved by methods

incorporating aromatized coffee oil-containing particles, such as those described in the

'368 and ' 178 patents, into an instant coffee product depends, in large part, on the

amount of such particles employed. The use of coffee oils in instant coffee does not

normally pose a problem at the low levels needed to provide only a package aroma.

However, a relatively large amount of particles must be employed to produce good

preparation aroma. This approach may lead to a product having an overwhelmingly

strong taste or aroma during consumption. Moreover, the more capsules that are

employed, the more capsule material, particularly coffee oil, that is introduced. The

added coffee oil accumulates as an oil film on the surface of the coffee beverage.

Such oil films are very apparent and are widely known to impair consumer acceptance

of instant coffee.

Further, the use of oils during the aroma entrapment stage involves processing

at temperatures above the freezing point of oil. At these temperatures, water is present-

as a liquid and can be detrimental. Methods for decanting the water therein have been

patented (Canadian Patent No. 2,091,276). Nevertheless, considerable amounts of aroma are unavoidably decanted with the water phase, and residues of water are left in

the oil which hastens degradation of the coffee aroma.

U.S. Patent No. 5,229,153 discloses a process for the fractionation of coffee

aroma in which the residual water phase left after aromatization of an oil by contact

with frost is used as a main aroma source to aromatize a second fraction of oil.

Because of the hydrophilic nature of this coffee aroma fraction, such a process is

relatively inefficient and the character of the coffee aroma entrapped in the oil is

significantly different from the original source.

The fixation conditions discussed above lead to changes in the chemical or

physical properties of the coffee aroma because of exposure to heat and moisture. In

addition, the efficiency of recovery of the most volatile compounds is low, and

partitioning of aroma between the water phase and the hydrophobic oil phase can

cause imbalance.

It is an object of the invention to provide methods for preparing coffee

aromatizing compositions which minimize the problems associated with previously

known methods such as flavor imbalance, heat or moisture-induced changes in

chemical or physical properties, and low efficiency. It is a further object of the

invention to provide such methods which can achieve these goals economically,

without the need for complex or expensive apparatus. These and other objects of the

invention will be apparent from the detailed description of the invention to follow. Summary of the Invention

The invention provides a method for preparing a coffee aromatizing

composition which comprises contacting a coffee aroma with a volatile organic carrier

liquid at a processing temperature at which said carrier is in the liquid state and at

which any moisture present is in the form of ice, and recovering an aromatized carrier

liquid, said carrier liquid having a freezing point below said processing temperature

and a boiling point above said processing temperature, a vapor pressure of at least

0.01mm Hg at 25°C and atmospheric pressure, and having a water solubility of not

more than 10% by weight.

Detailed Description of Preferred Embodiments

In accordance with the present invention, a coffee aromatizing composition is

prepared by contacting a coffee aroma, such as a coffee aroma frost, with a volatile

organic carrier liquid at a processing temperature such that any moisture present in the

aroma is in the form of ice. Physical properties of the volatile organic carrier liquid

are important. The carrier liquid must be liquid at the processing temperature at

which any moisture present is in the form of ice. Accordingly, the carrier liquid has a

freezing point below the prevailing processing temperature. The carrier liquid

freezing point is necessarily less than 0°C, preferably less than -5°C, and more

preferably less than -10°C.

A common source of coffee aroma is coffee aroma frost obtained from

commercial preparation of roasted and ground coffee and of instant coffee. Such

coffee aroma frosts include coffee aroma, C0₂, and water in the form of ice. When a carrier liquid is aromatized with a C0₂-contaϋning coffee aroma frost according to the

present invention, the processing temperature is such as to cause sublimation of the

C0₂. A processing temperature of 0 to -150°C is suitable for such sublimation, a

temperature in the range of -5 to -120°C is preferced, from -10 to -100°C is more

preferred, and from -20 to -80°C is most preferred. At these temperatures, C0₂ has a

significant vapor pressure and can sublime, while even the most volatile of the coffee

aroma compounds have a low vapor pressure and will be mainly retained in the liquid

carrier. As mentioned above, the carrier liquid will have a freezing point sufficiently

below the processing temperature such that it will remain liquid at the prevailing

processing temperature. For aromatizing with such frosts, a carrier liquid freezing

point of less than 0°C is necessary, a freezing point of less than -80°C is suitable, and

a freezing point of less than -10°C is preferable.

The vapor pressure of the carrier liquid is at least 0.01mm Hg at 25°C and

atmospheric pressure. Vapor pressure of the carrier liquid is preferably at least 0.5mm

Hg, more preferably at least 2mm Hg, and most preferably at least 5mm Hg, at 25 °C

and atmospheric pressure.

The boiling point of the earner liquid is suitably from 25 to 250°C, preferably

from 25 to 200°C, and more preferably from 25 to 100°C.

Density of the carrier liquids is preferably less than 1.0 g/cc at 25°C, more

preferably from 0.7 to 0.99 g/cc at 25°C, and still more preferably from 0.§ t 0.9

g/cc at 25°C. Carriers having a density of less than 1.0 g cc wiϊ_x float on the surface,

of water, resulting in a greater burst of preparation ar₀ma in instant coffee bevera.ge

applications. For use in encapsulated preparation aroma products such as those described in

co-pending U.S. Patent Application Serial No. 09/745,124, filed December 21, 2000,

the liquid carriers may have a water solubility of up to about 5 or 10% by weight and

are preferably water insoluble. In the present process, because any water present is in

the form of ice, water solubility of the carrier or, conversely, solubility of water in the

carrier liquid is not crucial. However, non-hydrophilic liquids are preferced and will

suitably be either insoluble in water or have a limited water solubility of up to about 5

or 10% w/w. Conversely, solubility of water in the carrier liquid may be up to about 5

or 10% w/w but is preferably essentially nil

Suitable volatile organic carrier liquids include the following:

* Includes values reported in the literature and estimates based on available data. Vapor pressure, density and water solubility (weight %) reported at 25°C. Not all compounds listed are approved for food use.

It is prefened, for simplicity, to utilize a single volatile carrier liquid.

However, more than one carrier liquid may be employed, and the selected carrier

liquids may be of different chemical classifications. Where more than one carrier

liquid is employed, it is preferred that the selected liquids are miscible with one

another and that they are of the same chemical classification.

The volatile liquid carriers are preferably bland, but may have an inherent

aroma. The amount of aroma generated by the carrier is generally small relative to the

aroma generated by the coffee aroma of the aromatized carrier liquid. In some cases,

the inherent aroma of the canier liquid will be essentially undetectable. In any event,

inherent aroma of a volatile carrier liquid may be reduced by conventional

deodorizing techniques such as adsorption, extraction or distillation. However, it is

possible to select a volatile carrier which has an inherent aroma which is appropriate for a coffee beverage. For example, fiiran and a variety of alkyl substituted furans

such as 2-methylfuran, 2-ethylfuran, and 2,5-dimethylfuran occur naturally in coffee

at extremely low levels in combination with a wide variety of other compounds, and,

when obtained from coffee, have inherent coffee-compatible aroma. These furans do

not occur naturally in coffee in sufficient quantity to be used economically as volatile

carriers, but they can be readily obtained from other sources. A volatile carrier liquid

with a fruity aroma, such as non-deodorized d-limonene which has a mild citrus

aroma, is a suitable carrier for aromas for dehydrated fruit-flavored coffee beverage

products.

The coffee aroma may be any coffee aroma obtained during coffee processing

such as the production of roasted and ground coffee and instant coffee. Such aromas,

and or the gas streams from which the aromas are obtained, may be fractionated or

may be purified to remove undesirable compounds as is done conventionally in the

art. Such aromas are usually obtained at low temperature, typically at cryogenic

temperatures, including temperatures below the freezing point of carbon dioxide.

Coffee aroma frosts which include carbon dioxide, water ice, and coffee aroma

compounds are widely used as a source of coffee aroma and are readily processed in

accordance with the present invention. As shown in the examples which follow, a

coffee aroma frost can be contacted directly with a volatile carrier liquid of the

invention or the frost can be contacted with the carrier liquid after sublimation of

some or all of the C0₂ from the frost. After such C0₂ sublimation, some or all of the

aroma compounds may be in liquid form. In any event, it is essential that the

processing temperature is such that any moisture present is in the form of ice at least until separation or recovery of an aroma-enriched liquid carrier from the aroma

source.

When the coffee aroma source is a C0₂-containing coffee aroma frost, it is

preferred to bring the frost and liquid carrier into contact at a temperature such that

C0₂ contained in the frost sublimes. However, it is not necessary to cause C0₂

sublimation, because aroma fixation can be achieved at temperatures below the

sublimation temperature of C0₂. When it is desired to effect sublimation of C0₂ from

a frost, contact with the liquid carrier is maintained for a time sufficient to effect such

sublimation, and preferably for a time sufficient to effect sublimation of substantially

all of the C0₂ contained in the frost. Contact time to effect sublimation will depend

on many factors, particularly the heat exchange rate. In general, contact time is set to

control the rate of C0₂ sublimation, and to effect mixing and equilibrium to ensure

fixation of aroma in the carrier. The rate of sublimation of the C0₂ is controlled to

avoid excessive bubbling and consequent product carry over, typically by adjusting

heat input to the vessel. Contact time with a frost is typically less than four hours.

For liquid coffee aromas, contact time is typically less than two hours.

The method of the invention can be carried out in readily available equipment,

either continuously, semi-continuously, or batch. For batch processing of an aroma

frost, a jacketed vessel equipped with an agitator for stirring and having a vent for

sublimed C0₂ is suitable. An appropriate amount of carrier liquid is added to the

vessel and chilled to processing temperature by coolant circulated through the jacket.

An appropriate amount of aroma frost is then added manually or in any convenient

mechanical manner such as by screw feeder. The rate of addition of frost is controlled, together with processing temperature (i.e., the temperature of the mixture

in the vessel) such that sublimation of C0₂ is effected. After C0₂ sublimation and

fixation of the aroma in the carrier liquid have been effected to the desired extent, the

contents of the vessel are removed and the aromatized carrier liquid is recovered by

separation from the water ice and any remaining frost. While it is preferred to add

frost to the carrier, it is also possible to add carrier to the frost. In that event, the

carrier should be chilled to prevent rapid C0₂ sublimation and melting of ice. During

the entire processing time, that is the time that the carrier liquid is in contact with the

aroma, the temperature of the mix is sufficiently low that any moisture present is in

the form of ice. After recovery of the aromatized carrier liquid, it is preferably kept

very cold to minimize aroma loss or degradation until it is used.

The method can also be carried out continuously or semi-continuously in

readily available equipment. For continuous processing, an elongated jacketed screw

conveyor vessel is suitable. The aroma and carrier liquid would be metered at

appropriate rates into one end of the vessel and the mixture moved through the vessel

by rotation of the screw. The mixture discharged from the other end of the vessel

would be passed through a screen or filter to separate the aromatized carrier liquid

from the ice or any remaining frost particles. Again, the temperature of the mixture

would be sufficiently low to ensure that any moisture present will be in the form of ice

during the entire process. Semi-continuous operation is readily accomplished in a

plurality of batch vessels operated alternately.

For processing of a liquid coffee aroma such as that remaining after

sublimation of C0₂from a coffee aroma frost, the aroma fixation method of the invention can be carried out by simple admixture of the carrier and aroma in similar

equipment. Temperature of the vessel contents are, again, maintained sufficiently low

to keep any moisture present in the form of ice.

The fixation of aroma into the volatile carriers can be carried out at

atmospheric pressure or under elevated or reduced pressure. Atmospheric pressure

fixation is ideal for aroma compounds with freezing points very close to the C0₂

sublimation temperature. High pressure fixation, where the frost is heated and

partially or totally molten before the introduction of the carrier, is preferred with

aroma compounds with higher freezing points, typically above -40°C.

For processing of aroma frost, after sublimation of the C0₂ is completed, it is

sometimes preferred to raise the processing temperature from a generally low

temperature suitable for C0₂ sublimation to a higher temperature just below the

melting point of water ice in order to facilitate fixation of aroma compounds that may

be trapped in water ice crystals. At these temperatures, typically about -15°C to -5°C,

partitioning of aroma into a water phase and transfer of water into the carrier do not

occur because water is present as solid ice.

The wide range of temperatures employed in the invention results from the

respective steps of the process. The fixation of the aroma compounds into the carrier

typically occurs at about -75 °C to -20°C during sublimation of the C0_2, while

temperature may be raised to as high as -5°C during removal of the aroma compounds

from the water ice. The low temperatures used are ideal to retain the roasted and fresh

aroma notes particularly well suited for jar and preparation aroma applications. The low temperature and the presence of the liquid carrier permit the rapid transfer of the

most volatile compounds.

The aroma frostcarrier fixation ratio, i.e., the ratio of the weight of aroma frost

to the weight of liquid carrier, that can be efficiently utilized in the invention can vary

widely. It is an advantage of the invention that high frostcarrier fixation ratios of as

much as 20:1 or higher can be employed, and that low-moisture aromatized carrier

liquids can be achieved at such high fixation ratios. These benefits are largely due to

the low processing temperatures of the invention which cause any moisture present to

be in the form of ice, and to the physical properties of the volatile carrier liquids of the

invention, namely their low freezing point, which enables the carriers to remain liquid

at the prevailing low processing temperatures, and their low water solubility. The

liquid nature of the carriers at these temperatures facilitates physical mixing of the

carrier and aroma. As a comparison, coffee oil typically has a room temperature

viscosity of about 100 to 150 centipoise which rapidly increases at lower

temperatures, whereas room temperature viscosity of the present volatile carrier

liquids is typically less than 10 centipoise and more typically less than 1 centipoise.

Further, since aromatization of a coffee oil carrier involves processing at temperature

at which moisture is present in the form of water, the amount of detrimental water in

the aromatized coffee oil carrier will increase as the amount of frost is increased.

However, in the present invention, the moisture content of the aromatized volatile

carrier liquids will be low because any moisture present during the process will be in

the form of ice. Frostcarrier fixation weight ratios of from 1: 1 to 20:1 are preferred,

and ratios of from 2:1 to 10:1 are more preferred. The present invention enables aromatization with coffee aroma frost at these fixation ratios, continuously or non-

continuously, with short processing times. By contacting the present low freezing

point, low water-soluble, volatile organic carrier liquids with coffee aroma frosts, it is

possible to achieve extremely high loading of excellent quality aroma.

The volatile carrier optionally can be pre-aromatized by other means prior to

aromatization using the method of the invention. Pre-aromatization can be effected to

utilize other available aroma sources, improve process flexibility, or beneficially tailor

the sensory attributes of the aromatized volatile carrier to specific product

applications. The volatile carrier may be pre-aromatized by direct or indirect contact

with a coffee aroma source including, but not limited to, whole or ground roasted

beans, native or aromatized oils, aqueous or solvent extracts, and steam condensates

or distillates.

Contact with roasted coffee or coffee oil requires any insoluble material or oil

transferred to the aromatized volatile carrier to be substantially removed to prevent

sediment and slick formation in beverage applications. This can be accomplished,

preferably before contact with aroma frost, using vacuum distillation, most preferably

high vacuum distillation at less than 10 μm Hg, to evaporate only aroma and volatile

carrier from the treated materials. The aroma and volatile carrier can then be

condensed under conditions, preferably cryogenic conditions, effective to produce a

substantially oil-free, liquid, aromatized volatile carrier. Any C0₂ that may be present

can be removed by sublimation and any moisture that may be present can be removed

by freezing to form ice that can be filtered out, these procedures being conducted at

any appropriate time during the process. While pre-aromatization requires additional processing steps, it can be an

effective way to impart desirable aroma components to the volatile carrier for specific

product applications. In addition, other established concentration and separation

techniques can be used in conjunction with pre-aromatization to improve process

efficiency or quality of the pre-aromatized carrier. For example, aqueous aroma

sources can be concentrated prior to use via low-temperature vacuum distillation or

membrane filtration to facilitate transfer of aroma constituents into the volatile carrier

while minimizing exposure of aroma to high processing temperatures that could lead

to loss or degradation.

Example 1

Coffee aroma frost produced from percolation vent gas of a commercial instant

coffee process was contacted with deodorized d-limonene carrier liquid in a vessel.

The frost contained less than 5% w/w water. Addition of frost to the vessel was

conducted incrementally over three hours while the temperature of the mixture in the

vessel was maintained between -75°C and -30°C, causing sublimation of the C0₂

content of the frost and fixation of coffee aroma in the carrier liquid. A water ice

phase was present in the mixture. C0₂ sublimation (evidenced by bubbling), the

presence of water as ice, and non-solidification of the mixture were used, together

with temperature measurements, to regulate the rate of the addition of the frost. After

the last portion of frost was added, the mixture was removed from the vessel and the

aromatized canier liquid was separated from the water ice present in the mixture.

Three tests were carried out, each using 1kg of the aroma frost and varying amounts of carrier liquid. The aromatized earner liquids were analyzed for coffee aroma content

by head space gas chromatography (HS-GC).

As a comparison, 72kg of the same coffee aroma frost was contacted with 45kg

of expelled coffee oil. After eight hours of sublimation of C0₂, equilibration, and

decanting, an aromatized coffee oil was obtained. Temperature during the

aromatization process was maintained between 15 and 25°C.

Results were as follows:

Although carrier aroma content was roughly proportional to the frost: carrier

ratio, independent of carrier type, it will be recognized that use of a volatile organic

canier of the invention can beneficially permit a higher frost: carrier ratio to be used.

In this example, the combination of low freezing point, low viscosity, and low

solubility of water in d-limonene permitted a much greater frost: canier ratio than

typically used for coffee oil, while beneficially producing a completely volatile

aromatized carrier having not only a high aroma content, but also a low moisture

content.

Example 2

The aromatized canier liquids of tests IB and IC of Example 1 were

encapsulated in instant coffee via emulsification in coffee extract and desiccation in instant coffee powder. 37.5g of Kenco™ Really Rich freeze dried instant coffee was

dissolved in 37g of water. 7.0g of the aromatized carriers of tests IB and IC were

emulsified into separate portions of the coffee solution and droplets of the solution

portions were dropped into liquid nitrogen to form frozen particles. The particles

were then separated from liquid nitrogen and dried in 1500g of milled (100 microns

average particle size), freeze dried (1% moisture) Kenco™ Really Rich instant coffee

for 48 hours. The capsules obtained were blended into Kenco™ Really Rich freeze

dried instant coffee at levels between 3 to 10% w/w. On preparing a brew with hot or

boiling water, a fresh and intense coffee aroma burst was released. The preparation

aroma impact and quality of the brews prepared with the aromatized capsules was

judged by an expert panel to be superior to brews prepared without the capsules.

Example 3

5kg of coffee aroma frost was produced from percolation vent gas of a pilot

plant instant coffee process. The frost contained 15% w/w water.

200g and 500g portions of the frost were used to aromatize lOOg of deodorized

d-limonene using the procedure of Example 1. HS-GC analysis was also carried out

as in Example 1. As a comparison, 700g of the same frost was aromatized with 445 g

of coffee oil After seven hours, C0₂ sublimation, equilibration, and decanting were

complete, 450g of aromatized oil was obtained. Results were as follows:

These tests show that the method of the invention is rapid and efficient.

Moreover, the low moisture content of the aromatized carrier, resulting in part from

the low temperature processing conditions, is also beneficial.

Example 4

One part of 2-ethylfuran carrier was contacted with 20 parts of frost collected

in scraped surface heat exchangers regulated at -120°C from roasted coffee bean

grinder vent gas. The addition of frost to the carrier was conducted incrementally, at a

rate suitable to control the temperature of the preparation between -75°C and -20°C.

C0₂ gently bubbled from the carrier. When the final portion of frost was added, the

water ice present in the preparation was separated from the aromatized carrier and the

sample kept at -60° C for analysis, sensory evaluation, and encapsulation. HS-GC

analysis gave 1000 GC counts.

Example 5

A mixture of 25.2g 24DE (dextrose equivalent) corn syrup solids and 2.0g

Hyfoama DSN hydrolyzed milk protein (Quest International) was dissolved in 15.8g

water. 7.0g of the aromatized carrier of Example 4 was emulsified into the solution, and then dropped into and dried in an excess amount of powdered 10DE corn

maltodextrin for 48 hours.

The capsules were sieved and the 1-3 mm fraction was incorporated in

Jacobs™ Zauber instant cappuccino mix at a level of 1.5% w/w. An expert panel

judged the aroma burst released on makeup of the beverage in 75 °C water as fresh,

roasted and intense, good quality coffee aroma.

Example 6

This example demonstrates aromatization of volatile organic carrier liquids

with a coffee aroma obtained by removing C0₂ from a coffee aroma frost by

sublimation.

lOOg of a coffee aroma frost collected from the vent gas of the fresh percolator

column of a commercial instant coffee process was placed in a 200mL beaker

positioned in a desiccator vessel. Sublimation of the C0₂ from the frost was

controlled by contacting the exterior of the beaker with an excess of dry ice pellets.

Temperature of the frost was then maintained at -75 to -40°C. The desiccator vessel

was closed, but included a vent to permit escape of the C0₂. The ice-containing liquid

aroma remaining in the beaker was kept at -40°C and contacted with 5g of deodorized

d-limonene at -20° C. After gentle shaking of the mixture, the aromatized canier

liquid was separated from the ice crystals. An expert panel evaluated the aroma

released from a droplet of this aromatized canier liquid placed on the surface of a cup

of hot coffee. The aroma burst was judged to be fresh and of good quality. Example 7

The following model frosts were prepared:

Fixation was then canied out as follows:

Frost 1:

A concentrated liquid aroma was prepared from Frost 1 by the technique

described in Example 6. Sublimation was stopped when 10% v/v of the initial aroma

frost remained in the 200mL beaker. The beaker was kept in dry ice.

lOg of deodorized, -60°C d-limonene was introduced into the beaker and the

preparation was gently shaken. After sublimation of the residual C0₂ still present

after the concentration of the aroma, the aromatized canier was transfened to a vial,

sealed and weighed. A mass balance indicated that 90% of the aroma was recovered.

Karl Fischer water analysis of the aromatized carrier showed that no water was present, thus confirming that no water had been condensed in the carrier from the

atmosphere during the aromatization process. Further, since some loss occuned

during the transfer of the mixture into the vial, actual efficiency is in excess of the

measured efficiency.

Frost 2:

Liquid coffee aroma was prepared from Frost 2 by the technique described in

Example 6. lOg of deodorized, -60°C d-limonene was introduced into the beaker,

and the preparation was gently shaken. The aromatized canier was transfened to a

vial, sealed and weighed. The mass balance indicated that 85% of the aroma was

recovered. Karl Fischer water analysis of the aromatized canier showed that no water

was present, thus confirming that no water had been condensed in the carrier from the

atmosphere during the aromatization process. Further, since some loss occuned

during the transfer of the mixture to the vial, actual efficiency is in excess of the

measured efficiency.

Frost 3:

lOOg of Frost 3 was placed in a beaker in an enclosed container and a slight

positive pressure was maintained in order to avoid moisture pickup from the

atmosphere. 11.7g of deodorized, -60°C d-limonene was introduced into the beaker.

The sublimation temperature was controlled to around -75°C. The beaker was

contacted with an excess of dry ice in the final stages to maintain a low temperature.

13g of aromatized d-limonene containing 10.7% w/w aroma was recovered. The following recovery efficiencies were measured (% by weight of aroma recovered in

carrier liquid based on weight of aroma in frost).

Frost 4:

lOOg of Frost 4 containing 1.6% aroma and 3% water was placed in a beaker in

an enclosed container and a slight positive pressure was maintained to avoid moisture

pickup from the atmosphere. ΪOg of deodorized, -60°C d-limonene was introduced

into the beaker. The sublimation temperature was controlled to around -75°C. The

beaker was contacted with an excess of dry ice in the final stages to maintain a low

temperature.

Water was present as ice and was separated by passing the liquid through a fine mesh

sieve. 14.4g of aromatized d-limonene was recovered which contained 12% w/w

aroma. The following recovery efficiencies were measured (% by weight of aroma

recovered in carrier liquid based on weight of aroma in frost):

Frost 5:

lOOg of Frost 5 was placed in a beaker in an enclosed container and a slight

positive pressure was maintained in order to avoid moisture pickup from the

atmosphere. 50g of deodorized, -60°C d-limonene was introduced into the beaker.

The sublimation temperature was controlled to around -75°C. The beaker was

contacted with an excess of dry ice in the final stages, to maintain a low temperature.

The water was present as ice and was separated by passing the liquid through a fine

mesh sieve. 54.4g of aromatized d-limonene were recovered which contained 2.7%

w/w aroma. The following recovery efficiencies were measured (% by weight of

aroma recovered in carrier liquid based on weight of aroma in frost):

Example 8 85g of the aroma frost of Example 3 was used to aromatize 17g of pre-

aromatized d-limonene following the procedure of Example 3. Moisture content of

the aromatized carrier liquid was less than 0.1% w/w and its HS-GC count was 350.

The carrier was pre-aromatized by liquid-liquid extraction of an aqueous coffee aroma

obtained from the vent gas of the fresh percolator column of a commercial instant

coffee process. Batch pre-aromatization was carried out by contacting lOOg of the

aqueous coffee aroma with 20g of deodorized d-limonene for about five minutes at a temperature of about 2°C, and the pre-aromatized carrier liquid was separated from

the aqueous phase. Pre-aromatization enabled efficient recovery of important flavor

compounds such as aldehydes and pyrazines which would normally be condensed and

lost in the water removal step typically conducted in conventional coffee oil

aromatization methods to minimize moisture content of the oil.

Claims (22)

What Is Claimed Is:

1. A method for preparing a coffee aromatizing composition which

comprises contacting a coffee aroma with a volatile organic carrier liquid at a

processing temperature at which said canier is in the liquid state and at which any

moisture present is in the form of ice, and recovering an aromatized carrier liquid, said

carrier liquid having a freezing point below said processing temperature and a boiling

point above said processing temperature, a vapor pressure of at least 0.01mm Hg at

25°C and atmospheric pressure, and having a water solubility of not more than 10%

by weight.

2. A method according to claim 1 wherein said coffee aroma comprises a

C0₂-containing coffee aroma frost.

3. A method according to claim 2 wherein the weight ratio of frostcarrier

liquid is from 1:1 to 20:1.

4. A method according to claim 2 wherein the weight ratio of frostcarrier

liquid is from 2: 1 to 10: 1.

5. A method according to claim 2 wherein said coffee aroma frost

comprises a fractionated coffee aroma frost.

6. A method according to claim 2 wherein said contact between said coffee

aroma frost and said liquid canier is effected at a temperature such that C0₂ contained in said coffee aroma frost sublimes and wherein said processing time is sufficient to

effect sublimation of substantially all of the C0₂ contained in said coffee aroma frost.

7. A method according to claim I wherein said processing temperature is

8. A method according to claim 1 wherein said coffee aroma comprises

water ice and coffee aroma obtained by removing C0₂ from a C0₂-containing coffee

aroma frost by sublimation of C0₂.

9. A method according to claim 1 or claim 2 wherein said processing

temperature is from -5 to -120°C.

10. A method according to claim 1 or claim 2 wherein said processing

temperature is from -10 to -100°C.

11. A method according to claim 1 or claim 2 wherein said processing

temperature is from -20 to -80°C.

12. A method according to claim 1 wherein more than one of said volatile

organic carrier liquids are employed.

13. A method according to claim 12 wherein said volatile organic carrier

liquids are miscible with one another.

14. A method according to claim 12 wherein said volatile organic carrier

liquids belong to the same chemical classification.

15. A method according to claim 1 wherein said volatile organic carrier

liquid is water insoluble.

16. A method according to claim 1 wherein said volatile organic carrier

liquid has a density of less than 1.0 g/cc at 25°C.

17. A method according to claim 1 wherein said volatile organic canier

liquid has a vapor pressure of at least 0.5 mm Hg at 25°C and atmospheric pressure, a

boiling point in the range of 25-250°C, and water solubility of not more than about

5% by weight at 25°C.

18. A coffee aroma composition according to claim 15 wherein said volatile

organic carrier liquid has a vapor pressure of at least 2.0 mm Hg at 25°C, a boiling

point in the range of 25-200°C, and a density in the range of 0.7 to 0.99 g/cc at 25 °C.

19. A coffee aroma composition according to claim 15 wherein said volatile

organic carrier liquid has a vapor pressure of at least 5.0 mm at 25°C, a boiling point

in the range of 25-100°C, and a density in the range of 0.8 to 0.95 g cc at 25°C.

20. A coffee aroma composition according to claim 1, wherein said volatile

organic carrier liquid comprises at least one member selected from the group

consisting of monoterpene hydrocarbons, esters, and alkyl furans.

21. A coffee aroma composition according to claim 1, wherein said volatile

organic canier liquid comprises at least one member selected from the group

consistmg of d-limonene, 2-ethylfuran, 2-me ylfuran, 2,5-dimethylfuran, and ethyl

acetate.

22. A method according to claim 1 wherein said volatile organic canier

liquid is pre-aromatized prior to said contacting with said coffee aroma.