Note: Descriptions are shown in the official language in which they were submitted.
65SS
This invention relates to the production of coffee
aroma principles useful in the aromatization of food products
generally and soluble or instant coffee in particular. More
particularly, this invention is concerned with a process of
obtaining coffee oil having balanced aroma principles and con-
trolled aroma quality and intensity from roasted coffee.
Many soluble or instant coffee powders are found to be
deficient in the aromas contained within fresh roasted and
ground coffee. In the case of soluble coffee powder, i.e., the
dried water extract of roasted coffee, a considerable amount of
the aromas may be lost in the process of dehydrating the extract
to the dry powder state. Generally, it is difficult to retain
or capture all of the aroma principles in a coffee extract due
to the volatilization and degradation of these aroma principles
in drying. Attempts have been made, however, to incorporate -~
coffee aroma principles into and onto a dried coffee extract. -~
These aromatization techniques have included a wide variety
of methods and have encompassed the utilization of aroma prin-
ciples derived from coffee by such methods as using the aromas
contained within grinder gas or roaster gas as well as the
aromas obtained by dry distilling or solvent extracting roasted -~
coffee. In addition, aroma principles useful in the aroma-
tization of soluble or instant coffee have been obtained from
roasted coffee by expressing the coffee oil contained therein.
Generally this method involves separation of the oil from
roasted coffee by dividing the coffee into smaller particles
and compressing these particlesg typically by the use of
expressing means. The expressed coffee oil contains quantities
of low, medium and high boiling aromatics such that when the
oil is plated on soluble coffee powder, it enhances the dried
extract with the desired characteristic coFfee aromas. -
However, any substantial amount or intensity of aromas supplied
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to the soluble coffee powder in this manner usually requires a
large quantity of expressed coffee oil to be supplied. This may
frequently cause the powder to have an unattractive wet appearance
and to be less free-flowing than a powder which is not plated
with the oil. Such a drawback is able to be overcome by concen-
trating or folding the aroma principles in a given quantity ~ ;~
of expressed oil and thereafter applying the oil containing
a larger amount of aroma principles to the soluble coffee
powder. Notwithstanding this advance, which is generally de-
scribed in Canadian Patent No. 603,954, the problem still remains
of maintaining or attempting to achieve a balance of the aroma
principles within coffee oil which has been expressed from
roasted coffee. Thus, in the subsequent treatment and handling -
of the coffee oil as well as the dried soluble coffee powder to
which the coffee oil may be applied, and also during the handling,
packaging and storage of the final product, certain of the aroma
principles may be lost because of their fugitive nature.
It has now been discovered that a coffee oil having
balanced aroma principles and controlled aroma quality and
intensity may be obtained from roasted coffee by expressing
coffee oil from roasted coffee by subjecting the roasted coffee -~
to a pressure of from 5,000 to 20,000 psi (350 kg/cm2 to 1400
kg/cm2) while passing an inert gas through, and maintaining
an environment of said inert gas over, the roasted coffee and -
the oil expressed therefrom. The roasted coffee is subjected
to the oil expressing operation in a pressing means, typically
any one of a large number of oil presses that are commercially
available, while maintaining the temperature of the coffee during
expressing at below about 175C and the temperature of the oil
being expressed at between 25 and 50C. Preferably, the inert
gas is carbon dioxide although other inert gases such as
nitrogen may be employed either alone or in
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combination with the carbon dioxide. A critical feature of the
process is that the flow rate at which the ;nert gas is passed
over the roasted coffee and the oil expressed therefrom should
be maintained at between about 0.1 and 2.0 cfm (between about
47 and 944 cm3/sec.) within and surrounding the pressing means.
To sorne extent, the flow rate may be varied within the afore-
mentioned limits, but care must be taken to ensure that the
flow rate is maintained within such limits since the aroma
principles are sought to be obtained in a balanced manner,
i.e., controlled amounts of the low, medium and high boiling
aromatics are desired. By regulating the flow rate of the
inert gas within the pressing means, it is now possible to ~-
control the quality and intensity of the aromas within the
coffee oil that is expressed from the roasted coffee. Moreover,
because of the balanced aromatics within the cofFee oil produced
by the process of this invention, the coffee oil as well as the
aroma principles contained therein are less costly to produce.
Thus, it is apparent that savings may be realized both in
labor and energy as well as in raw materials, that is, the
roasted coffee from which the coffee oil is expressed.
It should be mentioned that while inert gases have ~
previously been employed in the production of coffee oil having ~ -
aroma principles therein, the use of such gases has been
essentially for the purposes of serving as either a purging
blanket or a transfer force. Thus, coffee oil has been obtained
from roasted coffee by expelling the oil from the roasted coffee ~;
in an inert gas atmosphere so that the degradation of the
coffee aromas by oxygen is prevented. Also, inert gases have -~
been employed to purge the headspace of vessels used to store
coffee oil. As mentioned, inert gases have been further utilized
as a transfer force so as to transport oil from the various
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vessels and apparatuses utilized in coffee oil production and
subsequent utilization of the coffee oil in the plating of
soluble or instant coffee. Notwithstanding such conventional
uses of inert gases in the production of coffee oil, the present
discovery is predicated on the unexpected finding that by
maintaining an inert gas atmosphere over the roasted coffee
and the oil expressed therefrom and also passing such inert gas
at a specified flow rate over the roasted coffee and the oil
expressed therefrom, the aromatics within the coffee oil are
able to be balanced much more carefully with the result that
the coffee oil obtained has its aroma quality and intensity
critically controlled. It is theorized that the process of
the present invention results in a partial fractionation of
the aroma principles of the coffee oil. It may also be noted
that while maintaining and passing the inert gas over the ~ ~ -
roasted coffee and the oil expressed therefrom lead to the -;
production of a coffee oil having balanced aromatic principles, -
departure from the limits of flow rate results in unbalancing
the aroma principles within the expressed coffee oil. Thus, if ;`
an insufficient flow rate of the inert gas is not ensured, then
the deleterious effect of oxygen on the coffee oil and also ~;
an unbalancing of the aromatic principles therein may be noted.
Also, if the flow rate is permitted to exceed the limits which
have been critically established, it appears that all of the
aromatics may be effectively stripped from the expressed or
expelled oil. In either case, then the aroma principles become
unbalanced which is undesired.
In operating the pressing means so as to express`the
coffee oil from the roasted coffee, as mentioned previously,
any of a variety of commercially available presses or oil
expellers may be utilized. The roasted coffee from which the
oil is to be expressed or expelled is passed in the form of
particles into the pressing means. During the expressing
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operation, a pressure is developed on the expelled cake or
meal. Subsequently, the expelled cake or meal may be extruded
and cut into pellets for reintroduction into percolators with
normal roasted and ground coffee from which the soluble or
instant coffee is being produced and which may be later plated
with the oil expressed from the roasted coffee by the process
of this invention. During operation of the pressing means,
it is desirable to cool the roasted coffee from which the
coffee oil is being expelled so that the aromatic principles
do not become degraded by exposure to inordinately high tempe-
ratures which may be developed during the expressing operation.
The expressed coffee oil is discharged from the pressing means
and its temperature upon discharge in the range of from about
25 to 50 C. The expressed coffee oil may be then immediately
cooled and clarified as, for example, by centrifuging. The
coffee oil, having balanced aroma principles as obtained by
the process of the present invention, may be plated onto
soluble or instant coffee in amounts of from about 0.1 to
about 1%, by weight, based on the soluble or instant coffee
powder. As mentioned previously, however, the coffee oil may
have its aroma principles enhanced or increased by recovering
the aroma principles from a given quantity of coffee oil and
subsequently incorporating the concentrated aroma principles
in another quantity of coffee oil, thereby increasing the
overall concentration of aroma principles in the latter
quantity bf coffee oil. The inert gas, particularly carbon
dioxide, may be introduced into the pressing means by any ;~
suitable device such as gas nozzles.
In order that the present invention may be more
fully understood, but without in any way attempting to limit
it thereto, the following illustrative example is furnished.
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EXAMPLE
An Anderson* expe11er was charged with roasted whole
coffee beans and the feed rate of the roasted coffee to the
expeller was maintained at 300 pounds per hour. During the
operation of the expeller, the temperature of the roasted coffee
within the expeller was controlled to 160 C., the temperature
of the coffee oil expressed was noted to be 30 C. During
operation of the expeller9 carbon dioxide gas was admitted into
and shrouded the expeller at a flow rate of 0.3 cfm (142 cm3/
sec.). The run was allowed to continue for 16 hours and the
coffee oil expressed from the roasted coffee was recovered and
analysed by gas chromatographic methods at hourly intervals
following the start-up of the expeller. A similar run was made - ~ -
on the same equipment utilizing the same type of roasted coffee, `- !~
feed rates and other conditions except that the flow rate of
carbon dioxide gas was 2.5 cfm, the coffee oil was similarly
recovered and analysed. A third run was made on the same
equipment utilizing the same type of roasted coffee, feed rates
and other conditions except that there was no admission of,
or blanketing with, carbon dioxide, the coffee oil was similarly `~
recovered and analyzed. From the gas chromatographic data, it
was found that the coffee oil expressed by the process of the
present invention from roasted coffee produced a more balanced
aroma blend and more desirable aroma principles than the coffee `~-
oil obtained in either of the other runs. This finding was
further confirmed when the coffee oil from each of the runs was
subsequently plated onto soluble coffee powder and the oil-plated -~
soluble coffee powders were evaluated by an expert aroma panel.
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* Manufacturer's name ~ -
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