Note: Descriptions are shown in the official language in which they were submitted.
_ Case 3607
1 337853
1 COFFEE GLA~S & PROCESS FOR PRODUCING SA~
3 BACKGROUND OF TH~ INVENTION
S TECHNICAL FIELD
This invention relates to vegetable estracts, more
7 specifically estracts of coffee and processes for
producing aromatized coffee melts in a confined headspace
9 which on cooling of the melt forms hard coffee glasses
which trap the aromas. The coffee melt may also be
11 gasified prior to formation of the desired shaped coffee
glass. This invention provides an improved, economical
13 process for aromatizing and preparing shelf-stable coffee
products which have not suffered from heat damage and yet
15 may be guickly reconstituted in hot water to yield coffee
of escellent flavor and aroma. The process is
17 particularly suitable for producing aromatized stable
coffee glass.
19
PRIOR ART
21 The present invention is concerned with the
manufacture of vegetable estracts and, particularly,
23 instant coffee. The manufacture of instant coffee
involves estracting roasted and ground coffee beans with
25 water under conditions of high temperature and pressure
to form estracts which are dried with or without aromas
27 added by known means such as spray-drying, freeze-drying
or the like. *
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1 In an early effort to avoid drying of such coffee
estracts by Eskew, U.S. Patent 2,989,717, issued
3 March 22, 1960, a fifty-fifty mixture of concentrated
coffee estract and an invert sugar solution were
5 concentrated in a thin film evaporator to form a product
having four percent or less water which was pumped out of
7 the evaporator and formed on chilling rolls into small
flakes which were easily broken into a coarse product
9 before packaging. In this process, the product
temperatures esiting the evaporator ranged from 220F to
11 290F and the products produced had moisture contents of
about 1 to 4~ and were hydroscopic by reason of the
13 addition of large amounts of the invert suqars. This
type of processing was also applied by Turkot et al.,
15 U.S. Patent 2,908,630, issued September 29, 1959. While
the process of Eskew and Turkot et al. produced coffee
17 products without the need to spray-dry, a filler was
employed which is not suitable in today's market.
19 Furthermore, special packaging would be required to
reduce the chance of moisture contamination which would
21 be disastrous because of the hygroscopisity of the coffee
product produced.
23 In another attempt, Earle Jr., et. al.,
U.S. 3,419,399 patented December 31, 1968, prepared
25 aromatized soluble coffee doughs having a moisture
content of 9.5 to 12.5~ at a temperature below 140F and
27 then dryed the dough to 1-4~. This material was very
sticky and difficult to process.
29 Another attempt to produce dehydrated vegetable
estracts is disclosed by Risler, et. al., U.S.
31 Patent 4,154,864, issued May 15, 1979. Risler, et. al.
formed a paste or powder which is estruded into a
33 subatmospheric pressure chamber to puff the coffee
product. For esample, freeze-dried instant coffee
35 powder, having a moisture content of 2.5%, is estruded
~ 337853
1 into a chamber at 80 mb and cut to form grains about the
size of a pea which dissolve in cold water. When
3 compared to these grains estruded into atmospheric
pressure in Esample 5 of that patent, the products with
5 cellular internal structure are far more soluble.
In U.S. Patent No. 3,625,704 to Andre, et al, issued
7 December 7, 1971, dense flakes of instant coffee are
prepared and aromatized from roll-milled instant coffee.
9 In the field of flavor fixation, particularly of
essential oils, a number of patents have issued teaching
11 a carbohydrate glass to protect the flavor. For esample,
United States Patent 3,041,180 issued to Swisher
13 discloses a method for fising flavorants in an estruded
carbohydrate substrate. The product of the Swisher
15 invention is obtained by emulsifying an essentially
water-insoluble essential oil with a molten misture of
17 glycerol and corn syrup solids as the continuous phase,
estruding the emulsified mass in the form of filaments
19 into a cold fluid, preferably an organic solvent for the
essential oil which is a nonsolvent for the corn syrup
21 solids, followed by impact breaking of the solidified
filaments into small particles of usable form and then
23 holding the particles in the solvent, preferably for an
estended period, to remove essential oil from the
25 surfaces of the particles together with a substantial
portion of the residual moisture contained on and in the
27 particles. This methodology is conducted in escess of
130C.
29 United States Patent 3,704,137 to Beck discloses a
method for preparing an essential oil composition. His
31 method involves the cooking of an aqueous solution of
sucrose and hydrolyzed cereal solids until it i8 at a
33 boiling point of about 122C, and the water level reaches
a desired minimum. At this point, the heating is
35 stopped, the misture is agitated, and an emulsifier is
1 337853
1 added. The emulsifier is necessary in order for a
homogeneous solution to form. While the solution is
3 cooling, the essential oil and an antiosidant are added,
and are intimately mixed. The final mis is forced
5 through an estruder under air pressure. At this point,
about 0.5% by weight of the final composition of an
7 anticaking agent is added to prevent the particles from
stickinq.
9 United States Patent 4,004,039 to Shoaf et al.
discloses a process for the encapsulation of ~Aspartame~
11 in any number of matris forming materials. The product
is formed by creating a hot melt which, upon cooling, is
13 capable of forming a relatively amorphous matri~ within
which the sweetener is discretely dispersed.
EPO published patent application 0158460 to Pickup
et al., teaches a method for fising volatile flavorants
17 in a food-approved substrate, and, more particularly, to
a low-temperature methodology for fising volatile
19 flavorants in an extruded "carbohydrate-glass~
substrate. Volatiles or essential oils are dry blended
21 with 10-30% low molecular weight carbohydrate, food acid
or the like and at least 70% of a high molecular weight
23 polymeric carbohydrate which contains at least 95%
material above 1000 molecular weight. The dry misture is
25 estruded to form on cooling a hard glass-like substance.
While these methods have enabled workers in the art
27 to produce useful food products, they have not provided a
means for producing aromatized coffee glass which is
29 prepared from 100~ coffee derived material.
31 SUMM~RY OF T~F INVENTION
It has been discovered that a stable instant coffee
33 product can be prepared from a process which involves
obtaining a misture containing about 3% to 12%
35 (preferably above 4% to 9%) water and about 88% to 97%
1 337853
1 (preferably 91% about 96%) total coffee derived solids,
by either concentrating coffee extract or by
3 reconstituting instant coffee products either
spray-dried, freeze-dried or otherwise with water. If
5 desired, these two techniques may be combined. After
obtaining the moist coffee, it is subjected to heat and
7 shear to effect a molten liquid phase between 60C to
130C (preferably 70C-110C) within a confined
9 headspace. One or more coffee derived or synthetic
coffee aromas are added to the coffee melt and the
11 misture well blended to form a homogeneous misture. The
misture is shaped and rapidly cooled to affect a
13 transition from liquid coffee melt to a coffee glass with
a retention of at least 50%, preferably 70% and most
lS preferably 80% or more of volatiles and, finally, the
cooled product can be ground preferably at low
17 temperature or otherwise processed into useful coffee
products. We have found volatile retention by this
19 invention to be better than freeze drying or spray drying
coffee, particularly aromatized coffee.
21 This process avoids a dehydration or drying step
during the fisation process, and the volatile loss
23 associated with such a drying step. It also allows
fisation of the aroma under pressure in a confined area
25 which further prevents aroma loss.
In a preferred embodiment, the process for preparing
27 an improved soluble coffee product would be conducted in
an estruder and comprises: (a) moisturizing one hundred
29 percent coffee derived powder or concentrating one
hundred percent coffee derived estract to 88% to 97% or
31 preferably 91% to about 96~ by weight solids;
(b) subjecting the solids to sufficient heat and shear to
33 give a molten liquid coffee at 60C to 130C, preferably
70-110C, most preferably 80 to 100C under a confined
35 headspace; (c) adding natural or synthetic coffee flavors
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and aromas to the coffee melt under confined headspace; (d)
blending the coffee melt and the aroma stream to form a
homogenous mixture; (e) shaping and rapid cooling of the
homogenous mixture to affect a phase transition from coffee
melt to coffee glass with at least 50% retention of
volatiles preferably 70%; most preferably 80% retention of
volatiles; (f) grinding, preferably cryogenically, the
solidified mixture; and (g) drying the mixture to below 6%
if drying is necessary.
The coffee glass encapsulates and retains coffee
aromas and flavors. As the melt leaves the extruder, it is
important to rapidly cool the product to solidify the
matrix and retain the aromas and flavors.
In accordance with another embodiment of the
present invention there is provided a method of forming a
gasified coffee glass having a freeze-dried or roasted and
ground coffee appearance comprising: (a) forming a
mixture of from 88% to 97% total coffee derived solids and
3% to 12% water; (b) adjusting the mixture temperature to
60~C to 130C to form a melt; (c) injecting gas into the
melt under pressure in a confined area to form a soft,
homogenous, gasified melt; (d) forcing the melt under
pressure through an orifice to shape the gasified melt; (e)
rapidly cooling the gasified shaped melt leaving the
orifice to form a gasified homogeneous coffee glass; and
(f) recovering the homogeneous gasified glass.
In accordance with yet another embodiment of the
present invention there is provided a product having a
freeze-dried or roasted and ground coffee appearance, the
product being produced by the above noted process.
The advantages of coffee glass processing
includes (1) optimizing volatile retention for instant
coffees, (2) formation of small chips of concentrated
flavor which can be incorporated in coffee products, (3)
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1 337853
formation of new shapes for soluble coffee, (4) providing
increase coffee processing capacity by using concentration
and extruding equipment, rather than spray or freeze drying
to give final coffee products, (5) eliminating or
significantly minimizing dehydration required for
stability, (6) incorporation of coffee mannan and coffee
cellulosic hydrolysates in the coffee glass without
producing unusable hygroscopic products. It is important
in seeking these advantages to reduce the potential for
thermal degradation by limiting temperature and residence
time.
DESCRIPTION OF THE INVENTION
In accordance with the present invention, a
coffee glass product is prepared by forming a mixture of
88% to 97% coffee solids and 3% to 12% water at a
temperature of from 60C to 130C. The mixture is then
aromatized using a concentrated coffee aroma, synthetic
aroma or mixtures
_ _ 7 _ 1 3 3 7 8 5 3
1 thereof. Preferably, pure coffee derived aroma is
employed. The mixture is then throughLy mixed in a
3 restricted or confined area under pressure and rapidly
cooled to affect a phase transition and form a coffee
5 glass.
The coffee misture can be prepared from coffee
7 estract obtained by normal percolation by subjecting the
estract to falling film evaporators or other suitable
9 devices, to obtain a solids content of at least 88%. The
solids content, however, cannot esceed 97% since it is
11 important to form a misture which is a liquid at a
temperature between 60C to 130C and will form a coffee
13 glass upon cooling. The coffee misture can also be
obtained by mising dried coffee solids, spray-dried,
15 freeze-dried or otherwise, with sufficient water to
produce a moisture content between 3% and 12~.
17 Obviously, both means of obtaining a coffee
concentrate may be combined as by mising concentrated
19 coffee estract with dry soluble coffee to obtain the
desired moisture content. Whatever means is employed, a
21 uniform homogeneous coffee melt should be obtained
between 60C and 130C. In a preferred embodiment a melt
23 of 91 about 96% solids is prepared at 70C-110C.
This invention, in addition to working well with
25 conventionally estracted roasted and ground coffee
estract~, can also be applied to those estracts which are
27 obtained from coffee by heat, acid, enzymatic or base
hydrolysis. For esample, a portion of the coffee solids,
29 may be derived from hydrolyzed mannan which forms
oligomers having a DP anywhere from 1 to 8 such as
31 disclosed in U.S. 4,544,567. These materials are
generally obtained by high pressure, short time, high
33 temperature treatment of residual coffee grounds which
cause the mannan to be hydrolyzed to lower molecular
35 weight oligomers, having DP's up to 8. The coffee can
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1 also contain cellulosic sugars derived from the
cellulosic components of coffee which are produced by the
3 enzymatic, acid or base hydrolysis of such coffee solids.
The dry soluble coffee or concentrated estract used
5 in this invention has a composition dry basis percentage
as follows:
% Preferred %
9 Total Carbohydrates 15-50 30-40
11 Reducing Sugars 5-20 5-15
included in total
13 carbohydrates
Protein 5-15 6-10
17 Alkyloids 0-6 2-6
19 Chlorogenic Acid 2-35 5-15
21 Other Acids 2-12 4-8
23 Ash 2-16 5-9
We have found that while the composition of roasted
coffee has a considerable amount of caramelized sugar the
27 resulting glass is not so hygroscopic that it cannot be
stored at high temperatures because of the moisture
29 limitation used in preparing the glass melt.
Once the coffee misture is prepared, it may be
31 gasified by injecting into the misture and uniformly
blending various gases, such as nitrogen, air, carbon
33 dioside or other gases and mistures thereof, which will
cause a reduction in the density of the coffee misture
35 and allow flesibility and control of the final coffee
product density. Such gasification also helps in
37 producing improved solubility and has an efect on
lightening the color of the product, both useful when
39 designing new forms of coffee products using the glass as
a component.
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1 In addition, aromas are added, either with the
gasification step, or separately, such as by injecting
3 the aromas into the mixture and then homogenously
blending the mixture. It is necessary in adding aroma to
5 reduce the temperature effect on aroma by maintaining the
aromatized coffee melt at high temperature in a confined
7 space and then cool the mass in no more than three
minutes time. Thermal degradation and loss o the aroma
9 is prevented by cooling the melt immediately after it is
forced through an orifice or series of orifices when
11 shaping. On esitinq the orifices, the coffee melt
quickly solidifies and cools to a hard glass.
13 Alternatively, the mixture may be rapidly cooled within
the extruder by known means. It is important to cool and
15 resolidify the melt to form the glass. In either case,
we preferred to cool the aromatized coffee within 180
17 seconds, preferably within 120 seconds and, most
preferably, within one minute by using a liquid nitro~en
19 bath or other rapid cooling techniques.
The aromas can be stabilized in coffee oil, coffee
21 estract or in other art recognized ways. The aromas are
collected in art recognized ways.
23 The coffee glass is particularly valuable for
protecting and stabilizing natural and synthetic flavors
2S and aromas which may be added to the coffee. Apparently,
the high solids content of the molten liquid phase under
27 pressure allows rapid formation of a homogeneous
aromatized misture which can be immediately cooled to
29 affect a transition from coffee melt to coffee glass with
less than 50~ loss, more preferably 30~, and preferably
31 less than 20~ loss of volatile aromas. Optionally, inert
gas may be incorporated in the aromatized melt to protect
33 the aromas against osidation, to adjust density, and
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1 imp~ove solubility cf the final cooled melt or coffee
glass. Once cool, the coffee glass can the~ be broken
3 into the desired size.
Suitable flavors and aromas include aromas collected
5 from roasted and ground coffee called grinder gas, aroma
from coffee estract sometimes called vent Sas and aromas
7 from coffee oil, steam aromas, vacuum aromas and any
other known forms of coffee aroma and flavor. In
9 addition, other known forms of coffee such as colloidal
coffee, can be dispersed and incapsula~ed in the melt.
11 The following esamples are intended to illustrate the
present invention without limiting it.
13
EXAMP~E I
Soluble spray-dried and aqglomerated instant
*Maxwell House brand coffee having a 0.25 g/cm density at
17 a moisture content of 4.9% was hand fed into a *K-tron
volumetric feeder located on barrel 6 of Werner-
19 Pfleiderer twin screw e~truder~Model ~o. 1982 ZSK 57 mm50/2. Water was pum~ed into barrel 8 at 3.4 lbs/hr.
21 Liquid coffee aroma made in a manner taught in U.S.
Patent No. 4,574,089 at a density of 0.8S g/cm was
23 metered into the e~truder at 0.55 lbs/hr. The aroma
delivery system was pressurized to avoid aroma loss and
25 the aroma temperature was held to a masimum of 2C.
The coffee was processed through 5 barrels of the
27 11 barrel estruder. The 5 temperature zones were
controlled to achieve the following conditions:
29
8arrel No. Actual ~emD. (C)
6 (feed) 31
33 7 40
8 86
9 60
36
37 11 46
*Trade Mark
~1
..
1 337853
1 The e~truder operated at a rate of 85 lb/hr and 64%
torque with the screws turning at 6~ rpm.
3 The feed streams were homosenized and melted hy
mechanical heat into a coffee matri~. The product esited
5 the estruder at 88~C and 8~ moisture through a rope die
having two 3/4 diameter opening. The estrudate was quic~
7 cooled by immersion in liqui~ nitrogen and ~ormed a
brittle coff~e slass. Once brittle, the co~fee glass was
9 ground.
Aroma retention o~ 93~ was obtained by this process
11 as measured by a gas chromatograph using a purge and trap
procedure. Samples of feed powder spiked with the coffee
13 aroma at the stoichiometrically correct level and
aromatized estruded product were compared. The procedure
15 involved preparing a solution of the sample coffee and
water. The volatiles were driven from the coffee
17 solution onto a sorbant tube by the use of heat and a
helium gas sweep. An *Envirochem Unacon concentrator was
19 used to desorb the volatiles and transfer them onto a
fused silica column in a gas chromatograph equipped with
21 a FID (carbon) detector.
The aroma retentions obtained compared favorably with
23 those typically found with spray-drying (55%),
agglomeration (75% per pass) or freeze drying (65-75%).
The configuration of the twin 1290 mm self-cleaning
screws (shown just following) was assembled from elements
27 available through Werner Pfleiderer. It included riqht
handed kneading blocks (K) which acted as up and down
29 stream seals reducing the amount of added aroma
vaporizing out of the estruder.
31
33 P; tch of Fl i ghts ~ Q ~Q K ~Q ~ K~ K 4X40
La~g~h (n~ 30 8040 60 4~ 60 40 20 40 2040
*Trade Mark
~,
- 12 - 1 3 3 7 8 5 ~
1 EXAMPLE II
Soluble coffee, pre-moistured to 8~ moisture in a
3 ribbon blender, was fed at 3.3 #/hr to a Brabender single
screw 25/1 L/D ratio extruder with a 0.75~ diameter
5 2/1 compression ratio screw. Liquid aroma coffee made in
a manner taught by U.S. Patent 4,574,089 was pumped into
7 the e~truder at 0.05 #/hr. The screw was operated at
50 rpm and exerted 4500-5000 torque (Neutron Meters).
9 The 3 heatinq zones kept the molten coffee at 75, 80 and
80C respectively. The temperature controlled die
11 adaptor section was kept at 85 and coffee melts emerged
at 88C after an average retention time of
13 1.75-2 minutes. The coffee melts cooled quickly forming
a brittle glass.
The estrudate was ground in a Homoloid mill using 00
to 20 mesh screens, blended with spray-dried coffee
17 powder at 10% glass to 90% spray-dried material and
allowed to equilibrate.
19 A four-month accelerated storage study confirmed that
the product stored well, aroma remaining trapped in the
21 coffee matris for at least 10 weeks at ambient and
9 weeks at 35C as measured organoleptically.
23 If desired, other products can be prepared with
different aroma and coffee derived material.
~X~P!~ III
27 A lower density extruded form different from ropes
and sheet~ was prepared by using a gas injected vertical
29 tubing die. In this case, a C.W. 8rabender single screw
15/1 L/D ratio (0.75~ diameter) e~truder was equipped
31 with a 1/1 compression ratio screw. Soluble coffee (9.5%
moisture) was fed to the e~truder. The three heated
33 zones were set at 75C, 80C and 85C and the Brabender
vertical tu~ing die (ll/32~0D 9/32~ID) was heated to 85C.
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1 The soluble coffee passed through the e~truder at
rates of 2.0-34 lbs/hr e~iting the e~truder at 80-86C.
3 The screw was operated at speeds of 22, 33 and 40 rpm and
300-400 psi pressure was built up at the die. The melt
5 was estruded onto a teflon coated belt operated at
40-60 rpm. The extrudate formed tubes with a dark outer
7 surface and a glassy dark inner surface. These tubes
could be inflated by pinching the end forminq a thin
g walled (0.003~) bubble of coffee. The cooled glass
bubbles had fragile/brittle walls that when broken formed
11 light gossamer particles which are estremely soluble in
hot water.
13
E~ MPT.F IV
A C-37 mm corotating twin screw estruder manufactured
by Werner and Pfleiderer Corporation was used to esecute
17 these tests.
Beginning at the feed section, one of the screws was
19 fitted with 104S mm of conveying elements gradually
reducing in pitch from 60 mm to 26.7 mm, followed by
21 three sets of alternating 10 mm left handed conveying and
neutral elements, followed by a handed kneeding block at
23 the estruder discharge. The screw length totaled 1158 mm
and the estruder had seven barrel~. A matching profile
25 was constructed for the other screw. A sheet die
manufactured by Haake Buchler was attached to the
27 estruder discharge. This die had a 4 inch wide opening
and the gap was set at 0.005 inch. The die also
29 contained a pressure transducer which allowed calculation
of the die viscosity by standard techniques based on the
31 pressure loss through the die. The estruder operated
with barrel 1 (feed) at 70F; barrel 2/3 at 95F; 4/5/6/7
33 (discharge) at 212F; sheet die at 220F.
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1 337853
.
1 A commercially available spray-dried powder at 3%
moisture was fed to the C-37 mm operating at a screw
3 speed of 115 rpm. Water was introduced to the powder in
barrel 2 at a rate which produced a mixture at 6%
5 moisture. The wetted powder was mised and heated within
the estruder to form a homogeneous melt. The misture
7 esiting the die was at a temperature of 23SF and had a
viscosity of 2600 centipoise. The misture was rapidly
9 solidified to a brittle glass.
A second test was run using the same estruder/die set
11 up and conditions. The feed powder in the second test
consisted of 50% by weight commercially available
13 spray-dried powder (the same as used previously); 25% by
weight commercially available destrose at 0~ moisture and
15 25% by weight commercially available fructose solids at
0.3% moisture. Water was added to the powder blend in
17 barrel 2 at a rate which produced a misture at 6~
moisture. The melt exiting the die was lighter in color
19 and did not solidify to a brittle glass but stayed soft
and tacky. This test was continued by gradually reducing
21 the amount of water added to the coffee/monomeric sugar
blend. At the point where no water was added to the
23 estruder, the melt esiting the die continued to be light
in color. This misture had a moisture of 1.6% (no
25 process water added); a temperature of 235F and a
viscosity of 2550 centipoise and was soft and tacky.
27
