Note: Descriptions are shown in the official language in which they were submitted.
~063865
This invention is predicated on processing improvements
in the separation, recovery and concentration of roasted coffee
aroma constituents and the subsequent incorporation of the aroma
constituents into food products and generally entails an improve-
ment over the process disclosed by Feldman et al. in Canadian
Patent Number 603,954. Through the use of the improvements
described herein the Feldman et al. process can be more effi-
ciently practiced.
Some problems that hampered extensive commercial use of
the Feldman et al. process were that (1) the condensate could not
be removed from the condenser without undesirable prolonged
contact with air resulting in the loss and degradation of valuable
aroma constituents, (2) the condenser had to be emptied of the
cryogenic coolant and warmed every time the condensate had to be
removed thus putting a condenser out of action for a prolonged
period of time, wasting valuable coolant material, and due to the
condenser's large mass it remained cold for extended periods of
time thus hampering attempts to remove the condensate, and (3)
the physical state of the condensate in the condenser could not
; 20 be effectively controlled thus making handling difficult as effi-
cient operation makes desirable the formation of solid condensate
; on the collection surface.
In view of the above-mentioned difficulties encountered
with the Feldman et al. process and in order to effect an efficient
commercial process for the aromatization of food products,
particularly instant coffee, this invention is predicated on
processing improvements in the separation, recovery and concen-
tration of roasted coffee aroma constituents and the subsequent
incorporation of the concentrated aroma constituents in a food
product, particularly instant coffee.
The invention entails subjecting coffee oil in a dis- -
tillation chamber to distillation at sub-atmospheric pressures
-- 1 -
.. , .-; .. . .. . . .
.
. .
' ' ', , ~
.. . . .. .
~63~36S
and mild temperatures to separate aroma constituents therefrom
and condensing said aromatic constituents in a condensing chamber
on the outer surface of a heat-conductive sleeve removably and
snugly surrounding a heat-conductive container filled with a
coolant, then removing the sleeve with the condensed constituents
thereon. --
The condensed aromatic constituents in the condensing
chamber are preferably collected as a solid by maintaining a
sufficient pressure in the condensing chamber through the intro-
duction of an inert gas.
The sleeve with the condensed aromatic constituentsthereon is then preferably immersed into an edible substance con-
tained in a folding chamber in order to combine the condensed
aromatic constituents with the edible substance.
- In order that the invention may be more clearly under-
stood, reference will be made to the accompanying drawings in
which Figure 1 is a cross sectional view of the condenser of this
invention, and Figure 2 is a diagramatic sketch of apparatus
suitable for carrying out the invention.
- 20 Other features and advantages of the invention wil7 be
apparent from the following description taken in connection with
the accompanying drawings.
Coffee aroma constituents are separated by distilling
coffee oil at sub-atmospheric pressures and under mild tempera~
;, tures and then condensing the separated aroma constituents. The
coffee aroma constituents are separated from the oil in such a
manner that various desirable aroma constituent fractions can
be isolated and subsequently incorporated in a final product in
the proportions desired. Low boiling aroma constituents having
a fragrance like that of roasted coffee grinder gas and lacking
body form the bulk of the initial distilate. Medium boiling
aroma constituents and some higher boiling aroma constituents
. . .
~ - 2 -
.. . . ..
~0~3~365
having a burnt or smo~y roasted character are also separated from
the oil. As a result, the various aroma fractions can be propor-
tioned by controlling the temperature, pressure and period of
distillation to provide the desired levels of low, medium, and
high boiling aroma constituents to obtain a desired coffee aroma.
Generally, the coffee oil is obtained by expressing
roasted coffee at a temperature below 150C, and preferably at
about 130C. This is a sufficiently elevated temperature com-
patible with satisfactory yields of coffee oil and aroma therein.
The pressures exerted on the coffee to provide a high yield of
coffee oil and quality aromas cannot be stated precisely or
directly. However, coffee oil is expelled in an acceptable condi-
tion using apparatus estimated at exerting 5,000 to 20,000 p.s.i.
(approximately 350 to 1400 kg/sq cm) on the coffee. The pressures
for adequate oil yield and aroma quality can be determined in
terms of the temperatures of the expeller cake or meal and the
; expressed oil. The expeller cake (expressed roasted coffee or
coffee meal) should have a temperature below 150C and preferably,
a temperature of at least about 75C. The expressed oil should
have a temperature ranging from about 25C to 120C when measured
.
immediately after expression. Adherence to such expeller cake
and oil temperatures assures that the necessary pressures have
been applied to the coffee to recover oil therefrom without
undesirable modification of the aroma constituents therein.
The distillation of the aroma constituents from the
expressed coffee oil is preferably carried out within a tempera~
ture range of 15C to 100C with the preferred aroma constituents
being distilled at a temperature below about 60C. The oil is
maintained under a reduced pressure in the distillation chamber
of generally less than 50 mm and preferably less than 10 mm.
The most preferred distillation conditions involves subjecting
coffee oil at ambient temperatures (i.e., 20C to 35C), to a
pressure ranging from 10 mm to about 60 microns.
'
.:
~63865
The oil is preferably introduced into the distillation
chamber by a method that maximizes the liquid/gas interfacial
area. This allows a maximum of aroma constituents to be distilled
in a minimum of time. This method is preferably carried out by
atomization o~ the oil into fine droplets. This can be accom-
plished by using an impingement type atomizing nozzle that operates
by having the oil stream impinge, at high velocity, upon a pin
held directly at the exit of the nozzle orifice. Alternatively
the oil can be pxovided in a thin film for distillation; prefer-
ably in a rapidly moving film having a thickness ranging from 10
to 100 microns. The process of desorbtion can also be employed to
increase the efficiency and degree of separation of the aroma
constituents from the oil. Desorbtion involves sweeping the
coffee oil with an inert gas such as, for example, nitrogen,
carbon dioxide, helium, etc. in the distillation chamber and
thereby collecting the more fugitive aromatic constituents.
Referring to Figure 1 of the drawing the aroma consti-
tuents are then carried off as a gas stream and are condensed onto
the outer surface of a heat conductive sleeve 1 removably and
snugly surrounaing a heat-conductive container 2 which has a
coolant 3 therein. The heat-conductive sleeve is enclosed by a
condensing chamber 4 which has ports 5 and 6 to allow the passage
of the aromatic constituents within the space 7 between condensing ~-`
chamber 4 and the sleeve 1. The condensing chamber 4 also has a
removable cover 8 which seals an opening through which the sleeve
is removed from the container.
The sleeve is preferably a thin gauge metal and can be
kept in place snugly surrounding the container by a number of
- means. This can include the sleeve being screwed, latched,
hooked, etc. in place, or being held in place by friction between
the container and the sleeve or by the force of gravity. The
container is preferably of metal and is in contact with the sleeve
so as to maximize heat conduction between the container and the
~ '
-- 4 --
~3D638~5
sleeve. The container is also preferably cylindrical however this
is not meant to exclude other desired shapes such as a truncated
cone or a rectangular box, with the shape of the sleeve corres-
ponding to the shape of the container.
The coolant within the heat-conductive container can
have a temperature ranging from about 0C to about -26~C depend-
ing upon what aroma constituents one wants to collect. It is
possible though to condense all the aroma constituents with a
coolant on the order of -196C such as liquid nitrogen. Alter-
natively one may want to set up a fractional condensation system
~ utilizing several stages instead of one by using several of the
; above condensers in series each operating at a different coolant
temperature. For example, a first stage can be cooled to a
temperature on the order of 0C to -15C using a brine solution,
while a second stage can be cooled to a temperature on the order
of -80C using solid carbon dioxide as a coolant, while a third
stage can be cooled on the order of -196C using liquid nitrogen.
As the gas stream of volatile aroma constituents
enters the condensing chamber 4 through an inlet port 5 it comes
into contact with the cooled surface of the sleeve 1 and the
aroma constituents which condense form a frost thereon. The
constituents of the gas stream which are not condensed exit out
of the condensing chamber through an outlet port 6. After suf-
ficient frost has been collected on the sleeve the condensing
: :.
chamber preferably is isolated, vented tpreferably with an inert
gas) the cover 8 opened and the sleeve removed, preferably by use
of handle 9 on the sleeve. Preferably the apparatus can be so
arranged that while one condensing chamber is being isolated
another is activated thus providing for a continuously operating
condenser system. This can be done by connecting two condensing
chambers in parallel, with the required valving, between the
distillation chamber and the vacuum source (as shown in Figure 2).
Through use of this sleeve no significant amount of
- 5 -
1~i3865
frosk condenses on the container ancl therefore it is not necessary
to remove the coolant from the container to recover the frost.
Previously, due to the large mass of the container which collected
the frost on its surface, after the coolant was removed the con-
tainer retained the cold longer and when it was contacted with oil
to incorporate the frost into the oil, the oil would freeze onto
the container's outer surface and would have to be scraped off.
As well as being time consuming, this led to the use of a compli-
cated mechanical scraper and unwanted exposure of the coffee aroma
constituents to air. Now, due to the sleeve's low mass and high
heat transfer coefficient the frost can be easily and quickly
recovered when contacted with oil since there is little if any
freezing of the oil on the sleeve's surface, and exposure of the
condensed aroma constituents to air can be minimized due to the
ease with which the sleeve may be handled. The condenser can also
be quickly reactivated after inserting a clean sleeve onto the
container.
The condensed aroma constituents on the sleeve can be
collected by venting the condensing chamber preferably with an
inert gas, then removing the cover of the condensing chamber and
taking out the sleeve with the aroma constituents condensed
thereon in the form of frost and contacting the constituents with
an edible non-volatile fluid substance, e.g., an oil. The edible
substance serves as an aroma carrier enabling the aroma consti-
tuents to be conveniently added to a food product such as instant
coffee. The coffee aroma is preferably folded into the edible -
substance at a sufficiently high level to enable the concentrated -
aroma and aroma carrier to be incorporated into the food product
without imparting a "wet" appearance or causing poor flowability.
The preferred aroma carrier is coffee oil (expressed, solvent
extracted or otherwise obtained) which, due to the presence of
- natural emulsifiers therein, enables large quantities of aroma
. .
~ - 6 -
. . : . .; ~
10~865
frost to be combined with or incorporated into the oil. The
aroma is preferably added to the coffee oil to obtain a 2- to 10-
fold coffee aroma level ~aroma from 1 to 9 parts coffee oil
combined with 1 part coffee oil), the level also depending upon
how much aroma is to be added later to the food product such as
instant coffee. Preferably at least a 5-fold level of aromatized
oil is added to obtain a desired aroma level in a product such as
instant coffee without adversely affecting its appearance and
flowability.
This folding ~concentrating) step is preferably accom~
; plished by immersing the sleeve with the condensed aroma consti-
tuents thereon into an appropriate amount of coffee oil contained -
in a folding chamber (a chamber capable of being sealed to be
fluid and air tight), sealing the chamber from the air, flushing
the chamber with an inert gas and then allowing the aroma consti-
tuents to combine with the coffee oil. The appropriate amount of
; expressed coffee oil is determined by the final concentration of
aroma desired (i.e., 2- to 10-fold). So that the sleeve can be
immersed in the coffee oil it may be desirable, depending upon
the appropriate amount of coffee oil, that the folding chamber
have a dead space which the sleeve will fit around so as to allow
a minimum volume of oil to be in contact with a substantial
portion of the condensed aroma constituents on the sleeve's outer
surface. This can be carried out by having a vessel in the
folding chamber which the sleeve fits around. This vessel occu-
pies sufficient space in the folding chamber so that the appro-
priate amount of coffee oil in the folding chamber will contact a
substantial portion of the condensed aroma constituents on the
outer surface of the sleeve.
After sufficient time has elapsed for the aroma consti-
tuents to combine with the oil the aromatized oil is transferred
from the folding chamber, the seal broken, the sleeve removed and
the chamber resealed and recharged with fresh oil and flushed
. .
~ 7
. . .. . ................... ; : .:: .................. : .
,, .. , ,, , ,:: : ' :' : '
~063865
with an inert gas in readiness for another sleeve. By thus
having one folding chamber ready per sleeve, the exposure of the
aroma constituents to air is minimized to the transfer time of
the sleeve from the condensing chamber to the folding chamber.
Also the use of this folding chamber provides a simple method for
combining the aroma constituents with oil while minimizing con-
- tact of the oil and aroma constituents with air.
After the aroma constituents have been combined with
the oil the aromatized oil is then preferably blended in another
chamber with other aromatized oils in desired proportions thus
~ obtaining a homogenous aromatized oil and minimizing batch to
; batch variations.
Generally the most preferable aroma constituents from the
viewpoint of quality are those recovered as a frost. Further, in
order to be able to remove the condensed aroma constituents from
the condensing chamber it is also preferred that the aroma con-
stituents be in the solid state, i.e , recovered as a frost. The
sleeve permits the collection of the condensed aroma constituents
as a frost, so that when one removes the sleeve one also removes
all the aroma constituents frosted onto its outer surface. By
appropriate adjustment of the temperatures and pressure the
liquification of the recovered aroma constituents can be avoided.
The coolant temperature can be reduced or the condenser pressure
increased. With respect to coffee aroma constituents if the
pressure is raised to above approximately 60 microns, (preferably
140 microns,) and the coolant temperature kept at -196C the
condensate is then collected as a frost.
This is preferably accomplished by introducing an inert
gas (e.g., nitrogen, carbon dioxide, etc.) at a flow rate effec-
tive to control the pressure within the space between the sleeve
and the condensing chamber at a level sufficient to keep the
condensed aromatic constituents solid. Preferably the inert gas -
-- 8 --
, .~ . .~
~63865
is introduced in the distillation chamber, so as the pressure of
the inert gas is controlling the physical state of the condensate
in the condensing chamber as a solid, the inert gas is also
aiding in the separation of the volatile aromas from the coffee
oil in the distillation chamber by the process of desorbtion.
- The process of the instant invention can also be
; employed in-the separation of aroma constituents from other types ;~
of coffee oils such as solvent-extracted coffee oil.
In order that the present invention may be more clearly -
understood reference will now be made to the following exampleand to Figure 2.
EXAMPLE
; The distillation and condensing chambers were totally
enclosed and flushed with carbon dioxide, then depressurized to ;
approximately 20 microns, while the eirst feed tank was charged
with 140 pounds of expressed coffee oil.
The expressed coffee oil was obtained by subjecting
` roasted whole coffee beans to pressures of at least 5,000 p.s.i.
in an expeller and wherein said expressed coffee oil recovered
from the expre~sing operation had a temperature ranging from 25C
to 120C and the coffee meal residue had a temperature ranging
from 75C to 150C, the environment of the expressing operation
being cooled to a temperature below about 150C.
The oil was then pumped into the distillation chamber
11 at ambient temperature from the first feed tank 12 at pressures
up to approximately 1000 p.s.i.g. through an impingement type
atomizing nozzle 13 which operated by having a liquid stream at a
high velocity strike a pin held at the exit of the nozzle orifice
resulting in a wide angle, hollow cone, fine spray under the
vacuum environment of the distillation chamber 11. Meanwhile
nitrogen 14 was bled into the distillation chamber in order to
maintain a pressure of 140 to 160 microns. This was done ~o
_ 9 _ -
. ' ' ' ', ',, ~ . " . ~
. .
' ~63~16S
maintain the condensed aroma constituents in the condenser in the
solid state and to aid in separation of the aroma constituents
from the expressed coffee oil through the process of desorbtion.
The 140-pound oil charge was sprayed into the distillation
chamber 11 over a period of approximately 60 minutes. As the
partially spent oil collected in the bottom of the distillation
chamber, it was transferred by pumping to a second feed tank 19
wherein it was heated to a temperature of approximately 66C.
Isolating a second condensing chamber 20, as the gas
stream passed through a first condensing chamber 15 the aroma
constituents were condensed onto a thin gauge aluminum sleeve 16
cooled by and snugly surrounding a stainless steel container 17
filled with liquid nitrogen 18.
After the first charge had passed through the distil-
lation chamber 11 once, this first condensing chamber 15 was
isolated and a second condensing chamber 20 connected in parallel
with the first was put into operation by appropriate valve 21
adjustment. The first condensing chamber 15 was then vented to
atmospheric pressure using nitrogen gas and opened by unfastening
the hinged cover 22 of the condensing chamber 15. The sleeve 16
was removed manually and immediately placed into a folding
chamber 23 with 17.5 pounds of fresh expressed coffee oil therein.
The folding chamber was closed and then flushed with carbon
dioxide to remove any air.
A clean sleeve was inserted onto the container 17 in
the first condensing chamber 15, the chamber was then closed by
refastening the hinged cover 22 and depressurized. The first
condensing chamber 15 was then ready to be put back into opera-
tion as soon as the second condensing chamber 20 was isolated.
The preheated partially stripped oil from the second
feed tank 19 was then passed through the distillation chamber 11
in a manner identical to the oil from the first feed tank 12,
-- 10 --
~063865
except that on collection in the bottom of the distillation
chamber the totally spent (stripped) oil was transferred to a
collection tank rather than a feed tank. From the collection -~
tank this dearomatized oil was either routed to be used as fuel
or used in some other desired fashion.
At the end of the second stripping pass, the second
~ condensing chamber 20 was vented to atmospheric pressure using
; nitrogen gas. The sleeve 24 was then removed and immediately
placed into a second folding chamber 25 with 17.5 pounds of
freshly expressed coffee oil therein. The folding chamber 25 was
closed and flushed with carbon dioxide to remove any air.
The contents of the first folding chamber 23, which had
been allowed to sit for approximately 60 minutes, was then trans- ~
ferred to a 35-pound capacity oil pot 26 by applying pressure ~ -
using carbon dioxide gas to the folding chamber's headspace. The
first folding chamber 23 was then opened and the sleeve 17
removed and cleaned. The folding chamber was then closed and `charged with 17.5 pounds of fresh oil in readiness for another
aroma laden sleeve.
After an additional 60 minutes, the remaining 17.5
pounds of aroma laden oil from the second folding chamber 25 was
transferred to the identical 35-pound pot 26, wherein it was
blended with the oil from the first folding chamber 23 to produce
a homogeneous 35-pound batch of 5-fold oil. As before, the
sleeve 24 was removed and cleaned, and a new 17.5-pound charge
of fresh coffee oil was placed in the second folding chamber 25.
- Using a new charge of 140 pounds of fresh coffee oil,
the cycle was then repeated to manufacture another batch of 5-
fold oil.
The 5-fold oil was then plated on an instant coffee at
a level of less than one percent by weight resultiny in a product
- which has an unusually long storage life during which the original
balance, strength and fragrance of the aromas are substantially
retained without development of undesirable stale notes.
-- 11 -- ~
