ENCAPSULATION OF EXTRACT IN POROUS PARTICLES
CROSS REFERENCE TO RELATEDAPPLICATIONS
[01] This application claims priority to Provisional application Serial No. 61/478,261
filed April 22, 0 11, the disclosure of which is incorporated herein by reference
thereto.
FIELD OF THE INVENTION
[02] This invention relates to a process for recovering the extract produced during an
extraction process, particularly from a process of supercritical fluid extraction. In
particular, this invention relates to a process in which the extract, particularly a
fugitive extract, and often an ingestible extract, of an extraction process, such as a
supercritical fluid extraction process is recovered by depositing the extract within
the pores of a porous particle. In many cases, the resulting porous particle is
suitable for direct use as a food additive (such as a flavor or flavorant), or as a
nutraceutical.
BACKGROUND
[03] Extraction is a widely used unit operation for selectively removing one material
from a solid or liquid. Extraction of flavor and aroma constituents from natural
products using organic solvents is one common example.
[04] Supercritical fluid extraction (SFE) is yet another extraction method that uses a
supercritical fluid for selectively extracting one material from a solid or liquid. A
supercritical fluid is a liquid or a gas at normal, atmospheric conditions but exists
as a single homogeneous fluid phase above its critical temperature (TV) and
critical pressure (Pc) (known as the supercritical fluid region). As used herein,
the phrase "supercritical fluid" may be cither a pure substance or a mixture of two
or more substances.
[05] Supercritical fluids have a significant capacity to dissolve substances. The ability
of a supercritical fluid for selectively dissolving a substance during the extraction
process is influenced by the specific conditions of pressure and temperature
within the supercritical fluid region at which the extraction is performed and the
particular physical and chemical properties of die targeted extractant. Indeed, it is
this sensitivity of such solubility to modest changes in temperature and pressure
that has increased interest in SFE as a separation tool.
[06] Another aspect that has increased interest in SFE is that by selecting a
supercritical solvent with a proper critical temperature (Tc), the extraction process
may be conducted at a relatively low temperature, thus minimizing and possibly
avoiding denaturation or decomposition of heat-liable compounds and loss of
volatile components. As a result, supercritical fluid extraction is a technique that
has gained acceptance for the extraction of natural products, particularly products
for use as food additives, or as nutraceuticals
[07] The process of SFE generally consists of two essential steps: the extraction of
component (die extract) from a substance and the separation of the extract from
the supercritical fluid.
[08] In general, the substance for the extraction process is placed into an extraction
vessel and is contacted with a supercritical fluid at a specific condition of pressure
and temperature within the supercritical fluid region. For solid substances, the
extraction is usually conducted batchwise; for liquid substances the extraction can
also be batchwise, but alternatively may be continuous.
[09] After the extraction, the supercritical fluid, now-containing the material extracted
from the substance (the extract), is passed through a separator and by reducing the
pressure and/or changing the temperature, the capacity of the fluid to retain the
extract in solution is reduced and a separation between the extraction fluid and the
extract occurs. Thus, in many cases an expansion of all the fluid used for the
extraction is conducted in order to separate it in the gaseous state from the
extracted product which typically remains in the liquid state. Because of the
ability to remove substantially all of the extraction fluid from the material
extracted (the extract), SFE is often a preferred alternative to liquid extractions
using organic solvents, particularly in applications for recovering products
destined for use in a food product, or a nutraceutical product.
[10] Solvent extraction, including supercritical fluid extraction, has been used to
recover a variety of ingestible constituents, including aromas, flavors, vitamins,
antioxidants, caffeine, lipids and the like from natural sources such as plants and
animal tissue (plant materials and animal materials). As used throughout the
specification and in the claims plant materials and animal materials include any
material that is produced by or recovered from, either directly or indirectly, a
plant or animal source. Such plant materials would include as non-limiting
examples seeds, foliage, roots, bark, and fruits, both raw and processed in any
manner, as well as materials derived from such materials, such as cooking oils
and other by-products. In a similar fashion, animal materials include as nonlimiting
examples, tissues, including organs, and skeletal components, both raw
and processed in any manner, as well as materials derived from such materials,
such as cooking oils other by-products. Potential problems with the use of such
extraction methods, including supercritical fluid extraction, is the post-extraction
processing needed to recover the extract and the complications presented by the
subsequent storage and handling of the extract. Such processing and subsequent
storage and handling often can cause post-extraction degradation of extracts,
particularly with respect to delicate flavor volatiles and bioactive compounds.
11 Indeed, the recovery and storage stability of fugitive extracts poses a particular
problem. Fugitive extracts are extracts that arc likely to evaporate (because of
their high volatility), or deteriorate (often because of their susceptibility to
oxidation or susceptibility to even small changes in temperature), occurring in a
period of time shorter than the time before which they will be used due to time
spent during shipment or in inventory storage.
2] The general procedure of using supercritical carbon dioxide extraction in food
processing industry has been described by Raventos, et al., in 2002 (M. Raventos,
et al., Application and Possibilities of Supercritical C(¾ Extraction in Food
Processing Industry: An Overview, Food Sci Tech Int. Vol. 8 (5) (2002) 269-
284), the entire content of which is hereby incorporated by reference.
[13] U.S. Patent 4,198,432 describes the use of supercritical fluid extraction for
extracting flavor and aroma constituents from natural' spices such as black
pepper, cloves, cinnamon and vanilla.
[14] U.S. Patent 4,640,841 describes a process for extracting potential bitterness resins
from hops using supercritical carbon dioxide, absorbing the extracted resins on an
absorbent such as bentonite in a tank and them removing saturated absorbent from
the tank.
[15] U.S. Patent 5,961,835 describes a process in which a substance to be separated is
contacted first with a supercritical fluid in an extractor, after which the
supercritical fluid containing compounds leaving the extractor undergoes
nanofiltration for recovering a permeate flow containing light compounds and a
rctcntate flow containing heavier compounds.
[16] U.S. Patent 6,506,304 describes a process for recovering the supercritical fluid
from a mixture containing the supercritical fluid and a solute (extract) which
includes contacting the mixture with a molecular sieve membrane at a
temperature and a pressure in a critical region of the supercritical fluid and near a
critical point of the supercritical fluid so that a permeate rich in the supercritical
fluid and a retentate having a enriched concentration of the solute in the
supercritical fluid are generated.
[17] Sanganwar, Ganesh P., and Gupta, Ram B., "Dissolution-Rate enhancement of
fenofibrate by adsorption onto silica using supercritical carbon dioxide,"
International Journal of Pharmaceutics, Vol. 360 (2008), pp. 213-218 describes
the use of supercritical extraction as a way to load, i.e., adsorb, a poorly water
soluble drug, i.e., fenofibrate, onto a high surface area carrier, i.e., non-porous
fused silica. By using supercritical extraction as a way to dissolve the drug the
problem caused by contamination of residual extraction solvent in the final
product is avoided.
[18] Finally, pending U.S. Patent Application Serial Number 12/723,100, entitled
Anti-Caking Agent for Flavored Products, filed March 12, 2010, describes the use
of mcsoporous silica particles in a method for flavoring food products wherein a
flavorant is loaded in the pores of the silica particles. The entirety of the
disclosure of this application also is incorporated herein by reference.
Th present invention involves an improved method of recovering extracts,
particularly fugitive extracts and especially ingestible extracts produced from an
extraction process, particularly from a supercritical fluid extraction process and
for producing a product that is suitable for direct use as a food additive, such as a
flavoring, a flavor enhancer, a taste enhancer, aroma, an aroma enhancer, or
another functional ingredient, or as a nutraceutical. The method also improves the
retention and integrity of the extract This result is especially important for
fugitive extracts.
BRIEF SUMMARY OF THE INVENTION
[20] The present invention provides a process for recovering an extract, particularly a
fugitive extract and especially an ingestible extract from a mixture of an
extraction fluid and the extract, comprising:
a. contacting the mixture of the extraction fluid and the extract with a
contained volume of porous particles suitable for human consumption, the porous
particles having pores of a size which permits diffusion of the mixture of
extraction fluid and extract into the porous particles, and
b. changing a property of the extraction fluid to cause extract to deposit
within the pores of the porous particles.
[21 The method finds particular utility in the recovery of fugitive extracts and
ingestible extracts.
[22] In a particularly useful embodiment, the present invention provides a process for
recovering a fugitive extract from a mixture of an extraction fluid and the fugitive
extract, wherein the mixture is recovered at an elevated pressure from a
supercritical fluid extraction, comprising:
a. contacting the mixture of the extraction fluid and the fugitive extract with
a contained volume of porous particles suitable for human consumption, the
porous particles having pores of a size which permits diffusion of the mixture of
the extraction fluid and the fugitive extract into the porous particles;
b. changing a property of the mixture of the extraction fluid and the fugitive
extract to cause fugitive extract to deposit within the pores of the porous particles
separate from a gaseous extraction fluid;
c. separating the gaseous extraction fluid from the porous particles, and
d. removing porous particles, containing deposited fugitive extract, from the
contained volume.
[23] Th previous method finds particular utility in the recovery of ingestible extracts.
[24] The invention also relates to the porous particles containing the captured extract
within the pores of the particles as a product of the various methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[25] Figure 1 is a schematic flow chart of a process of the present invention as
described in further detail below
[26] Figure 2 is another schematic flow chart of a process of the present invention as
described in further detail below.
[27] Figure 3 is a schematic flow chart of the experimental super critical carbon
dioxide extraction procedure used in connection with Examples 3 and 4.
[28] Figure 4 is a schematic flow chart of the experimental super critical carbon
dioxide extraction procedure used in connection with Example 3.
[29] Figure 5 is a schematic flow chart of the experimental super critical carbon
dioxide extraction procedure used in connection with Examples 3 and 4.
[30] Figure 6 is a schematic flow chart of the experimental super critical carbon
dioxide extraction procedure used in connection with Examples 3 and 4.
DETAILED DESCRIPTION OF THE INVENTION
[ The use of fluid extraction for recovering fugitive constituents, including fugitive
ingestiblc constituents such as aromas, flavors, flavor enhancers, aroma
enhancers, taste enhancers, antioxidants, vitamins, bioactives, functional
ingredients, nutraceuticals, phytochcmicals, tastants, and natural colors and the
like from natural sources such as plants, marine sources and animal tissue has
become widespread. An ingestible extract or constituent is one that can be safely
ingested by an animal, including humans.
[32] Fluids that are considered harmless with regard to taste, health and chemical
composition are particularly suitable for use as the extraction solvent in
connection with the present invention. A non-exhaustive list of potential
extraction fluids includes carbon dioxide, water, ethane, propane, nitrous oxide,
ethylene, trifluoromcthanc, and tertafluorocthanc. Carbon dioxide is the fluid of
choice given its lack of toxicity, low explosion risk, ready availability at low cost
and high solvency in its supercritical state.
[33] The invention also contemplates the use of compatible co-solvents, (also referred
to as entrainers) such as water, ethanol and propylene glycol, for increasing the
solubility of the desired extract (e.g., for enhancing selectivity) in the extraction
fluid, and particularly in a supercritical extraction fluid. Again, co-solvents that
are considered harmless with regard to taste, health and chemical composition
should be used.
[34] Supercritical fluids, in particular, optionally in admixture with the co-solvents or
entrainers enumerated above, generally possess the ability to extract desired
components from a variety of substances, often natural compositions such as plant
materials, marine sources and animal tissue, while limiting or avoiding any
chemical change in the extract as a consequence of the extraction. This is
particularly advantageous with respect to fugitive extracts and ingestible extracts.
[35] The critical point for carbon dioxide is 7.38 MPa at 304.7° K (about 31° C). The
corresponding information concerning the critical point for other fluids suitable
for use in the extraction process, when conducting the extraction under
supercritical fluid conditions in connection with the present invention can be
readily determined from the scientific literature. As noted carbon dioxide is the
fluid of choice and the SFE conducted with carbon dioxide is generally conducted
at a pressure between its Pc and 35 MPa and at a temperature between its Tc and
120° C. An extraction process using supercritical fluid extraction operating at a
pressure above 10 MPa is typical.
[36] In its broadest aspects, the present invention is not limited by the nature of the
extraction process itself. Rather, the extraction process simply constitutes the
process by which the mixture of an extraction fluid and the extract is produced.
As a result, in its broadest aspects, the present invention is not limited to any
specific apparatus or any specific procedure for conducting the fluid extraction,
including a supercritical fluid extraction, which can be conducted in any
convenient and acceptable manner either batchwise, or continuously.
[37] Nonetheless, the use of supercritical extraction, in particular, in combination with
the other process aspects of the present invention is particularly advantageous; as
the process of supercritical extraction presents a unique integration between the
initial separation of the extract from is native source and the subsequent recovery
of the extract within the pores of the porous particles, as described in more detail
hereafter.
[38] In the context of supercritical extraction, in particular, U.S. Patent 7,648,635, for
example, describes a method and a related device for conducting a supercritical
fluid extraction, d e entire content of which is hereby incorporated by reference.
[39] In a batch system, the substance to be subjected to extraction and the extraction
fluid, such as a supercritical fluid, can simply be added to the extractor, i.e., often
a high pressure vessel, optionally fitted with some means for agitating its
contents, and the mixture is allowed to reach an equilibrium level of extracted
material (extract) in the extraction fluid, such as a supercritical fluid. For solid
substances, the material generally is converted to an extractable form by crushing,
grinding, flaking or other convenient size reduction technique. Then, the
extraction fluid bearing the extract is separated from the residual substance that
was subject to the extraction. In a continuous extraction process, the extraction
fluid can be passed in contact with the liquid substance being treated in either a
countercurrent or a co-current manner.
[40] As will be understood by those skilled in the art, if the pressure, temperature and
residence time for conducting an extraction, particularly a supercritical fluid
extraction, of any specific substance is not known, it can readily be determined by
routine experimentation. As with the pressure and temperature at which the
extraction process is conducted, if the treatment ratio between the extraction fluid
and the substance being treated also is not known it too can be determined by
routine experimentation.
[41] As will be appreciated by those skilled in the art, conducting the extraction at
lower temperatures is often preferred as a way of minimizing any loss or
degradation of fugitive extracts, including potentially thermally sensitive extracts.
As a result, many extractions may be conducted between 30° C and 100° C, and
often between 40° C and 60 ° C.
[4 Again, in its broadest aspects the present invention is not limited to any specific
procedure for conducting the initial extraction, including a supercritical fluid
extraction, which can be conducted in any convenient and acceptable manner
cither batchwisc or continuously.
[43] Following the initial extraction, such as a supercritical fluid extraction, the
mixture of the extraction fluid and the extract, such as a fugitive extract and
particularly an ingestible extract, is ultimately put into contact with porous
particles that are suitable for human consumption, i.e., are suitable for ingestion.
Typically, the porous particles are retained in an enclosed volume or container,
such as a tank or other vessel that can accommodate the condition (for example
the specific temperature and pressure) of the fluid carrying the extract. In the case
of a supercritical fluid extraction, the mixture of the extraction fluid and the
extract will typically be at an above-atmospheric pressure, i.e., at an elevated
pressure.
[44] Usually the porous particles arc uniformly porous particles. Particularly suitable
are porous silica (silicon dioxide) particles having a substantially uniform pore
diameter. These particles are suitable for ingestion by animals, particularly
humans.
[45] One class of suitable particles may have a highly ordered hexagonal
mesostructure of consistently sized pores having substantially uniform diameter.
The high level order of the pore mesostructure is apparent when viewing
mesoporous particles under transmission electron microscopy (TEM). Those
skilled in the art will understand that these are but one class of porous silica
particles that can be used in practicing the method of the present invention and the
invention is not limited only to porous silica particles satisfying these
characteristics.
[46] As recognized by those skilled in the art, porous silica (silicon dioxide) particles
having a substantially uniform pore diameter can be made by a variety of
techniques and the present invention does not depend on the use of any specific
method.
[47] For example, one class of suitable particles can be formed by an acid catalyzed
condensation reaction, which includes a templating agent, typically a surface
active agent or surfactant. In one suitable method, in particular, an acidic, e.g.,
mineral acid, solution of tetraethyl orthosilicate (TEOS) and ethanol is blended
with a templating solution containing ethanol, water and a templating agent, such
as an amphiphilic surfactant, and the blended mixture is heated while stirring.
One example of a suitable amphiphilic surfactant is a nonionic tri-block
copolymer composed of a central hydrophobic chain of polyoxypropylene flanked
by two hydrophilic chains of polyoxyethylene. Suitable amphiphilic surfactants
are sometimes referred to as poloxamers, and arc available under the trade name
Pluronics. The molecular structure of Pluronics in general is EO POmEO , with
EO representing ethylene oxide monomer units, PO representing propylene oxide
monomer units, n representing the average number of EO monomer units, and m
representing the average number of PO monomer units. For Pluronic P 04, for
example, n-27 and m=61 and the average molecular weight (MW) is 5900 g mo .
For Pluronic F127, for example, n=65.2, and m=200.4 and the average molecular
weight (MW) is 12600 g/mol.
[48] As the mixture of the TEOS and templating agent is stirred and heated, the
surfactant forms highly ordered micelles which, upon removal of the surfactant in
a final step, ultimately leave behind the porous structure within the silicon dioxide
matrix. n one approach, after stirring and heating, the TEOS/surfactant mixture
is aerosolized in an oven at high temperature (in one embodiment, at a
temperature of over 250° C) to produce a powder. The powder then is calcined in
an oven at very high temperature (in one embodiment, at a temperature of over
600° C) until the polymer matrix is fully formed and the surfactant and any
remaining solvent is removed, leaving a powder comprising discrete,
approximately spherical silicon dioxide particles with a highly ordered internal
porous structure.
[49] Uniformly porous, approximately spherical silica particles represent a particularly
useful class of porous silica particles for use in the context of the recovery of an
extract in accordance with the present invention, particularly the recovery of an
extract from a supercritical extraction process in accordance with the present
invention. The integrity of such approximately spherical particles make them
especially suited for the high pressures and large pressure changes encountered in
the processing encountered in a supercritical extraction.
[50] The porous particles for use in the present invention can be separated/classified
according to their outside diameter. Particles that range in particle sizes between
3 and 50 microns in diameter, usually between 3 and 20 microns and often
between 3 and 5 microns in diameter and having pores sizes smaller than 500
nanometers, usually smaller than 100 nanometers can be obtained and arc
especially useful in the present invention, especially particles that are
substantially spherical in shape. Particularly suitable particles are those with
highly ordered and substantially uniform pore sizes ranging between 1 nanometer
and 100 nanometers, such as between 1 and 50 nanometers, often between 2 and
25 nanometers, and usually between about 2 nanometers and 12 nanometers. The
porosity of suitable particles will typically have a surface area (BET surface area)
of at least 200 m /gm, more often at least 300 m /gm, usually at least 500 m /gm,
often at least 600 m /gm and particularly useful are particles with a porous surface
area of at least 1000 m /gm and up to 1,400 m /gm and higher. In the following
Examples 3 and 4, a templated mesoporous silica substrate was used in which the
analysis of random selected samples exhibited a BET surface area within the
range of 230 to 430 m /gm.
[51] Mesoporous particles with a substantially uniform pore diameter of about 3
nanometers can be produced using the processing specifically described above
and cetyl trimethyl ammonium bromide (CTAB) as the templating agent.
Mesoporous particles with a substantially uniform pore diameter of about 10.5
nanometers can be produced using a templating agent comprising Pluronic PI04
with polypropylene glycol added to core of the micelle. In a preferred
embodiment, about 0.18 grams polypropylene glycol (PPG) swelling agent is
added for every gram of P 04 in the synthesis. Different templating agents can be
used to produce particles with other substantially uniform pore sizes.
[52] For more details concerning the preparation of porous silica materials potentially
suitable for use as the ingcstiblc porous particles in connection with the present
invention please see U.S. Patents Nos. 5,858,457; 6,334,988; 6,387,453 (RE
41,612); 6,638,885; 7338,982 and 7,405,315 and pending U.S. Patent Application
Serial Number 12/723,100, published as U.S Published Patent Application No.
201 1-0223297, all of which are incorporated herein in their entirety by reference.
Nonetheless, as noted earlier, the present invention is not limited to these
methods, but can take advantage of any method that is suitable for producing
porous particles, especially porous silica particles with a substantially uniform
porosity and especially substantially spherical particles.
[53] In any event, the porous ingestible particles have pores sufficiently sized to
permits ready diffusion of the mixture of extraction fluid and extract throughout
their volume. In this way, the pores of the porous particles are filled with a
mixture of the extraction fluid and the extract.
[54] In order to deposit and retain the extract in the porous ingestible particles, a
property, such as the temperature and/or pressure of the mixture of the extraction
fluid and extract is changed. For example, when the extraction process employs a
supercritical fluid extraction process, the extraction mixture recovered from the
extraction will be at an elevated pressure, though often at a sub-critical value.
Typically, the properties, i.e., temperature and pressure, of the mixture of the
extraction fluid and extract are controlled so that the mixture remains in the liquid
state at least until the mixture is brought into contact with the porous particles and
permeates the porosity of the particles. Eventually, the pressure of the extraction
fluid is reduced, or both the temperature and the pressure of the extraction fluid
are altered to facilitate deposition of the extract within the pores of the porous
ingestible particles and separation of the particles rom some and preferably all of
the extraction fluid.
[55] For example, in the case of a process that employs supercritical fluid extraction as
the extraction process, the change in the properties of the extraction fluid causes
or facilitates the extract to separate, e.g., to precipitate, from the fluid and deposit
within the pores of the porous particles.
[56] The phase separation between the extraction fluid or extraction solvent and the
extract, often also referred to as the solute, may occur after the fluid containing
the extract has permeated the pores of the porous particles and thus occurs within
the contained volume of the porous particles in the pressure vessel (i.e., within the
contained volume of the recovery vessel itself. n particular, by changing a
condition of the extraction fluid its solvating power is reduced by the change in
properties (e.g., a change in state caused by a change in pressure and/or
temperature) so that the extract deposits in and throughout the pores of the
ingestible porous particles. In the case where the extraction fluid is recovered
from a supercritical fluid extraction process, the separation is preferably caused
by reducing the pressure of the extraction fluid to a condition where the extraction
fluid converts at least in part to a gaseous state. The temperature also can be
altered, for example either reduced, or increased in order to assist in the
deposition of the extract within the pores of the ingestible porous particles. Still
other combinations of a temperature change and/or a pressure reduction may be
used in the broadest aspects of the present invention to cause or facilitate the
desired separation, for example a phase separation, between the extraction
solvent, possibly comprising the solvent recovered from a supercritical fluid
extraction, and the extract.
[57] In the case of a process which obtains the mixture of extraction fluid and extract
from a supercritical fluid extraction process, the gas produced from the extraction
solvent recovered from the supercritical fluid extraction, now freed of some if not
all of the extract, is discharged from the contained volume of the separation vessel
(the recovery vessel) and, following any temperature adjustment in a heat
exchanger and a pressure increase in a pump or compressor, can be re-circulated
to the extractor in its supercritical state for further use in the extraction.
[58] The porous particles now loaded with extract are separately removed from the
contained volume of the separation vessel (recovery vessel) and are recovered as
the desired product, i.e., particles containing deposited extract. Given the use of
silica particles and depending upon the nature of the extract, the particles
containing the extract are often directly suitable for human consumption.
[59] The present invention also contemplates providing one or more barriers or
coatings on the exterior surface of the porous particles following the capture of
the extract within the pores. Such barriers or coatings could include diffusion
barriers, barriers that melt when placed into a warm environment, and barriers that
dissolve in an aqueous or specific pH environment. Melt barriers can include,
among other things, edible waxes or lipids. Diffusion and dissolution barriers can
include gelled proteins, hydrocoUoids, carbohydrates, starches, and
polysaccharides, among others. The subsequent release or extraction of the
extract from the pores of the particles is influenced by providing sets of particles
with barriers made of different materials, of different thicknesses, of different
diffusion or dissolution rates, or a combination of these. Such barrier coatings
can be applied by known techniques, such as spraying, sprinkling or panning.
[60] The application of such barriers or coatings can help stabilize and preserve the
integrity of fugitive extracts captured within the pores of the porous particles.
[61 ] Figure 1 illustrates a simplified schematic flow chart of a process of the present
invention.
[62] A natural material, such as a natural spice (e.g., vanilla, cinnamon, cloves, black
pepper and the like) or a plant material (such as orange peels) is introduced into
the extraction vessel 10 through inlet 1. The natural material can be fed
batchwise or continuously depending upon the specific details of extraction vessel
10 and the material. An extractant, such as dry C0 in a supercritical state, is
separately introduced into the extraction vessel 10 though inlet 2. Again,
depending upon the specific details of the extraction vessel 10, the supercritical
CO can be added for batchwise or continuous processing. In the extraction
vessel 10, a mixture of the extraction fluid and an extract (caused by selective
extraction of the extract (such as a fugitive and possibly ingcstiblc extract such as
flavor and aroma constituents) from the natural material) is created and is
removed though outlet 3. Spent natural material, i.e., natural material having a
reduced content of the flavor and aroma constituents is removed from the
extraction vessel 0 in outlet 4.
[63] In some circumstances, it may be desirable to include water, or another polar cosolvent,
in the extraction fluid to alter the polarity of the extraction fluid and
accordingly modify the spectrum of the extracts recovered from the natural
material being treated and possibly influence the deposition of extracts within the
porous particles in accordance with the present invention. By including a more
polar co-solvent with the main extraction fluid, one should be able to enhance the
extraction of polar (e.g., hydrophilic) extracts, including polar aroma and flavor
constituents and may also impact how these extracts are deposited into and
throughout the pores of the porous particles. Fortuitously, certain plant and
animal materials that can be processed in accordance with the present invention
inherently contain residual moisture. By subjecting these materials to an
extraction process, and particularly a supercritical extraction, in a manner which
allows these materials to retain their inherent moisture during the extraction, one
should be able to capitalize on the material's inherent moisture to facilitate a
greater recovery of desirable polar extracts during the extraction and within the
porous particles. This aspect of the invention is illustrated hereafter in connection
with the extraction of orange constituents in Example 4.
[64] The mixture of the extraction fluid and an extract in conduit 3 then is passed into
the contained volume of vessel 20 where the mixture containing the extract
permeates the pores of the uniformly porous particles, such as uniformly porous
silica, that are held in inventory in the vessel 20, and allows the extract to
eventually be deposited into and throughout the pores of the porous particles, e.g.,
porous silica. The porous particles, e.g., porous silica, can be introduced into
vessel 20 through inlet 5. The property of the mixture of the extraction fluid and
the extract is altered within vessel 20 in a way that causes or facilitates the extract
to be deposited into and throughout the pores of the porous particles, e.g., porous
silica. Thereafter, the porous particles,, e.g., porous silica, containing the extract
is removed from vessel 20 in outlet 6 separate from spent extraction fluid
recovered in outlet 7.
[65] Figure 2 illustrates another schematic flow chart of yet another embodiment of the
present invention. In Figure 2, a source of extraction fluid, such as liquid CO2, is
obtained from storage tank 10 is chilled in chiller 20, is pumped to a supercritical
pressure above about 000 psi in pump 30 and is introduced into supercritical
extraction vessel 40 through inlet 9. The supercritical extraction vessel 40 has
been previously supplied with a natural material, such as orange peels 11 from
which a desired extract is to be recovered. Alternatively, the supercritical
extraction vessel 40 could be charged with a non-polar liquid containing a desired
extract, such as an oil that contains flavor components, such as a spent cooking
oil. The supercritical extraction vessel 40 is fitted with a heater 45 to permit
maintaining the contents of the vessel at a suitable temperature. Within vessel 40
the supercritical CO2 extraction fluid and the natural material are contacted in a
manner to cause the desired selective extraction of various constituents of the
natural material, including the ultimately desired extract or extracts, into the
extraction fluid/solvent.
[66] Under the control of forward pressure valve 50, the pressure of the mixture of the
extraction fluid and extracted constituents is reduced partially to cause or
facilitate a first fraction of the extracted constituents to separate from the
remaining mixture of the extraction fluid and extracted constituents. For
example, a reduction in pressure from greater than 1000 psi to about 700 psi may
be suitable for this first stage. This first fraction of extracted constituents is
recovered separately from the mixture in separator 60, which also is fitted with a
heater 6 1 to permit maintaining the contents of the separator 60 at a suitable
temperature. The first fraction of extracted constituents is thus recovered in
vessel 62. Under the control of forward pressure valve 51, the pressure of the
mixture of the extraction fluid and remaining extracted constituents is further
reduced, for example down to about 350 psi, this time in the presence of suitable
porous particles, such as porous particles of a uniformly porous silica to cause or
facilitate the desired extract to be deposited within and throughout the pores of the
porous silica in infuser 70, which also is fitted with a heater 7 1 to permit
maintaining the contents of the infuser 70 at a suitable temperature. The porous
silica containing the desired extract is thus recovered in vessel 72. The nowgaseous
CO extraction fluid is discharged through valve 52 and conduit 53.
[67] Several advantages are realized by causing the extract to be deposited directly
from the extraction fluid into the pores of the porous particles. For example, with
direct deposition of the compounds into the porous silica particles one is able to
eliminate any need for intermediary recovery and processing steps, which in the
case of a fugitive extract, such as highly volatile aroma or flavor essences, such as
thermally unstable or thermally sensitive compounds, such as easily oxidized
compounds and the like in particular, enhances the overall recovery and quality of
the isolated and recovered extract. Also, one can tailor the property of the porous
particle in a way both to maximize the recovery of the desired extract and
optimize its subsequent use, such as it use as a source of aroma, such as its use as
a food additive, such as its use as a flavoring, such as its use as a flavor enhancer,
such as its use as a taste enhancer, or its use as another functional ingredient, such
as a nutraceutical.
As noted above, by subsequently coating the porous particles with the captured
extract, the stability and integrity of the captured fugitive extract may be
preserved even longer.
[69] For best results, the extract, either by itself or in conjunction with an additional
carrier fluid or solvent (including the extraction fluid), should exhibit wetting or
partial wetting of the surface of the porous particles, such as porous silica
particles so as to facilitate the mixture of the extraction fluid and extract
permeating the porosity of the porous particles, especially porous silica particles.
An extract or a mixture containing the extract exhibits desired wetting behavior
when a drop of the extract or mixture is applied to a flat, horizontal surface made
of the same material that makes up the porous particle and the drop exhibits a
contact angle of less man 90°. Nonetheless, the present invention is not limited
solely to the capture of extracts and extract mixtures that exhibit wetting behavior,
since the extraction fluid, particularly extraction fluids recovered from
supercritical fluid extraction processes, introduces even non-wetting extracts into
the pores of the porous particles and the change in state (e.g. liquid to gas) of
these extraction fluids causes the extract to be directly deposited inside the pores
of the particles.
[70] The extract-loaded particles, optionally coated, can then be used in a wide variety
of products, including in connection with food products, including beverages, and
with nutraceutical products, limited only by any restriction on the use of the
extract itself. Advantages of the present invention include improved stability of
the extracted material in the final product, particularly improving the retention of
the functional properties of a fugitive extract; improved shelf-life of the final
product (protection of the extracted material from degradation or volatilization);
improved ease of incorporation of the extracted material into a final product and
improved products for healthier food and beverage options and health and
wellness offerings.
[71 In particular embodiments, the present invention relates to
1. A process for recovering an extract from a mixture of an extraction fluid
and the extract, comprising:
a. contacting the mixture of the extraction fluid and the extract with a
contained volume of porous particles suitable for human consumption, the porous
particles having pores of a size which permits diffusion of the mixture of
extraction fluid and extract into the porous particles, and
b. changing a property of the extraction fluid to cause extract to deposit
within the pores of the porous particles.
2. The process of embodiment 1 for recovering an extract from a mixture of
an extraction fluid and the extract, wherein the mixture is recovered at an elevated
pressure from a supercritical fluid extraction, comprising:
a. contacting the elevated pressure mixture of the extraction fluid and the
extract with a contained volume of porous particles suitable for human
consumption, the porous particles having pores of a size which permits diffusion
of the mixture of the extraction fluid and the extract into the porous particles;
b. changing the property of the mixture of the extraction fluid and the extract
to cause extract to deposit within the pores of the porous particles separate from
gaseous extraction fluid;
c. separating the gaseous extraction fluid from the porous particles, and
d. removing porous particles, containing deposited extract volume.
3. The process of embodiment 1or 2 wherein the changing of the property of
the mixture of the extraction fluid and the extract comprises reducing the pressure of the
mixture.
4. The process of embodiment 1, 2 or 3 wherein the extract is a fugitive
extract.
5. The process of embodiment 1, , 3 or 4 wherein the fugitive extract is also
an ingestible extract and the porous particles containing the extract are suitable for human
consumption.
6. The process of embodiment 1, 2, 3, 4 or 5 wherein the porous particles arc
porous silica particles.
7 The process of embodiment 1, 2, 3, 4, 5 or 6 wherein the extract is
selected from the group consisting of aromas, flavors, flavor enhancers, aroma enhancers,
taste enhancers, antioxidants, vitamins, bioactives, functional ingredients, nutraceuticals,
phytochemicals, tastants, and natural colors.
8. The process of embodiment 1, 2, 3, 4, 5, 6 or 7 wherein the extraction
fluid is carbon dioxide.
9. A process for recovering an extract from a plant material or an animal
material comprising:
(1) performing an extraction of the plant material or animal material using an
extraction fluid to produce an extract in admixture with the extraction fluid;
(2) contacting the mixture of the extraction fluid and the extract with a
contained volume of porous particles suitable for human consumption, the porous
particles having pores of a size which permits diffusion of extract into the porous
particles, and
(3) changing a property of the extraction fluid so that extract deposits within
the pores of the porous particles.
10. The process of embodiment 9 wherein the extraction is a supercritical
fluid extraction.
11. The process of embodiment 9 or 10 wherein the extraction fluid is
supercritical carbon dioxide.
12. The process of embodiment 9 10 or 1 wherein the porous particles are
porous silica particles.
13. The process of embodiment 9, 10, 11 or 12 wherein the extract is selected
from the group consisting of aromas, flavors, flavor enhancers, aroma enhancers, taste
enhancers, antioxidants, vitamins, bioactives, functional ingredients, nutraceuticals,
phytochemicals, tastants, and natural colors.
[72] The invention also relates to the porous particles containing the captured extract
within the pores of the particles as a product of the various embodiment of the
methods.
EXAMPLES
[73] Th following examples constitute specific embodiments of the present invention
but are not intended to limit it.
EXAMPLE 1
[74] "Fried Potato Chip" Flavor is extracted via a supercritical CO2 extraction process
from used potato chip fryer oil and/or fried potato chips. Thereafter, the mixture
of CO2 and ingestible "Fried Potato Chip" flavor are directed to a vessel
containing a uniformly porous silica. As a consequence of contact between the
mixture of CO and ingestible "Fried Potato Chip" flavor and the porous silica,
the pores of the porous silica become filled with the mixture of liquid CO2 and the
ingestible flavor extract. Then, the pressure of the liquid CO2 is reduced, or both
the temperature and the pressure of the fluid are altered to values, causing the
flavor extract to separate and deposit within the pores of the silica. This porous
ingestible silica containing the "Fried Potato Chip" Flavor is added to salt to form
a seasoning and topically applied to reduced fat or baked potato chips, providing a
sensory experience more similar to that of a fried potato chip.
EXAMPLE 2
[75] Oranges are processed via a supercritical C0 2 extraction process in such a way to
extract the ingestible compounds responsible for flavor and the phytochemicals.
Thereafter, the mixture of C0 and these ingestible extracts are directed to a
vessel containing a uniformly porous silica. As a consequence of contact between
the mixture of C0 2 and the ingestible extract and the porous silica, the pores of
the porous silica become filled with the mixture of the liquid C0 2 and the
flavor/phytochemical extract. Then, the pressure of the C0 is reduced, or both
the temperature and the pressure of the extraction fluid are altered to values
causing the flavor/phytochemical extract to separate and deposit within the pores
of the silica. This silica containing the orange flavor and phytochemicals is added
to instant oatmeal for an enhanced flavor and health experience.
EXAMPLE 3
[76] In this example Supercritical C(¾ fluid extraction (SFE) of Lay's Classic Potato
Chips was performed and the resulting extract was collected in three sequentially
arranged separators and in a final cold trap by the following protocol.
[77 Th potato chips (the average thickness of an unbroken chip was 0. cm) were
ground using a mortar and pestle then the ground potato chip particles were
sieved between 0.24 and 0.14 cm. 60 grams of the ground potato chips then were
placed in a sample basket. The sample basket was placed in a SOOcc supercritical
extraction vessel containing a 60 micron sintered disk at the entrance and exit of
the vessel. The ground potato chips were contacted (extracted) with supercritical
fluid (CCb) at 4000 PSI (about 27.6 MPa) and 35°C at a flow rate of 0.02 kg
CCVmin. The resulting extract then was passed through a series of separators,
where the pressure was reduced at each to cause the extract to separate from the
CO2. The reduced pressure at the first separator was 3000 PSI (about 20.7 MPa).
The reduced pressure at the second separator was 2000 PSI (about 13.8 MPa).
The reduced pressure at the third separator was 1000 PSI (about 6.9 MPa). A
cold trap was placed at the vent to collect any remaining volatile flavor
compounds. The apparatus arrangement for each test is schematically illustrated
in Figures 3 through 6.
[78] In the various tests, about 0.3 grams of a substrate (mcsoporous silica) was placed
in one of three different locations in the SFE set-up. Four experiments were
performed as outlined below:
1) Without substrate
2) Substrate placed in-line between Separator 2 and Separator 3;
3) Substrate at the base of Separator 3, and
4) Substrate in the Cold Trap
[79] The cold trap sample not containing the substrate was collected via a hexane
wash.
[80| Four key flavor compounds in the recovered extracts were selected to measure in
terms of the amount collected suitable for indicating the relative ratios of each.
The four compounds were methional, phenylacetaldehyde, dimethyl-ethylpyrazine
and t,t-2,4-decadienal. Methional and phenylacetaldehyde are both
Strecker Aldehydes arising from a Maillard Reaction during the frying process.
Dimethyl-ethyl-pyrazine can be categorized as a Pyrazine resulting from the
Maillard Reaction during the frying process. The t,t-2,4-decadienal compound
results from oil oxidation.
[81] Tables 1-4 hereafter show the relative amounts of these four key flavor
compounds (1) methional; (2) phenylacetaldehyde; (3) dimethyl-ethyl-pyrazine;
and (4) t,t-2,4-decadienal which were collected at each location during recovery
of the extract in each of the 4 experiments. The data was measured by GC-MS
(gas chromatography-mass spectrometry) where a SPME (solid phase microextraction)
procedure was followed for all the samples with the exception that the
cold trap samples without substrate collected by hexane washes followed a liquid
injection process.
[82) In Classic Lay's Potato Chips these four key flavor compounds (1) methional; (2)
phenylacetaldehyde; (3) dimethyl-ethyl-pyrazinc; and (4) t,t-2,4-dccadienal are
typically present in me following relative amounts respectively: (1) 5.00, (2) 2.90,
(3) 0.15 and (4) 0.10.
[83] From an analysis of the data it can be shown that the relative ratios of these four
key flavor compounds are better maintained in the extracts recovered from the
substrates than in the extracts collected without the substrate. For example, the
extract recovered in the substrate tended to have a lower level of the oil oxidation
product, t,t-2,4-decadienal, than compared to extracts recovered without the
substrate. As a result, the substrate recovered extracts tended to be closer to the
flavor composition of the Classic Lay's Potato Chips.
EXAMPLE 4
[84) In this example Supercritical CO2 fluid extraction (SFE) of orange peel (Test
series A) and orange fruit (Test Series B) was performed and the resulting extract
was processed through three sequentially arranged separators and in a final cold
trap by the following protocol.
(85] Hamlin variety oranges were processed in the following manner to produce
material subjected to supercritical carbon dioxide extraction. In one set of
experiments (Test Series A), the peel of ten oranges were washed with deionized
water, sliced, frozen with liquid nitrogen, ground in liquid nitrogen in a stainless
steel blender and stored at minus 80 °C until used. This orange peel material will
be identified as "liquefied orange peel." n a second set of experiments (Test
Series B), ten oranges were washed with deionized water, the peel was removed
by hand (along with as much of the white albedo as could be removed), the fruit
was separated into individual wedges from which any large seeds were removed,
each wedge was cut in half, the halves were frozen in liquid nitrogen, ground in
liquid nitrogen in a stainless steel blender and stored at minus 80 °C until used.
This orange material will be identified as "liquefied whole orange."
[86] One hundred grams of either the liquefied orange peel (Test Series A), or the
liquefied whole orange (Test Series B) then were placed in a sample basket in the
respective series of tests. The sample basket was placed in a 500cc supercritical
extraction vessel containing a 60 micron sintered disk at the entrance and exit of
the vessel. The respective orange materials were contacted (extracted) with
supercritical fluid (C0 ) at 4000 PSI (about 27.6 MPa) and 35°C at a flow rate of
0.02 kg C(Vmin. The resulting extract then was passed through a series of
separators, where the pressure was reduced at each eventually causing extract to
separate from the C0 . The reduced pressure at the first separator was 3000 PSI
(about 20.7 MPa). The reduced pressure at the second separator was 2000 PSI
(about 13.8 MPa). The reduced pressure at the third separator was 1000 PSI
(about 6.9 MPa). A cold trap was placed at the vent to collect any remaining
volatile flavor compounds. The apparatus arrangement for each test is
schematically illustrated in Figures 3, and 6.
[87] In the various tests, about 0.3 grams of a substrate (meso oro us silica) was placed
in one of two different locations in the SFE set-up. Three experiments were
performed in each of Test Series A and in Test Series B as outlined below:
1) No Substrate
2) Substrate at the base of Separator 3, and
3) Substrate in the Cold Trap
[88] In particular, in Test Series A, 0.32 g and 0.34 g of substrate was placed at the
base on Separator 3 and in the Co d Trap respectively; in Test Series B, 0.32 g
and 0.26 g of substrate was placed at the base on Separator 3 and in the Cold Trap
respectively.
[89] The cold trap samples were collected via a hcxane wash.
[90] Ten key flavor compounds in the recovered extracts were selected to measure in
terms of the amount collected suitable for indicating the relative ratios of each.
The ten compounds were valencene, geranial, carvone, terpine-4-ol, linalool,
limonene, p-cymene, octanal, ethyl butyrate and acetaldehyde.
[91] Table 5 shows the overall amounts of flavor components (both with limonene and
on a limonenc-frce basis) recovered in Test Series A and Table 6 shows the
overall amounts of flavor components (both with limonene and on a limonencfree
basis) recovered in Test Series B.
Table 7 shows the Test Series A results with substrate and Table 8 shows the Test
Series B results with substrate providing the relative amounts of the ten key flavor
compounds which were collected at each of the two enumerated locations during
recovery of the extract. The data was measured by GC-MS (gas chromatographymass
spectrometry) where a SPME (solid phase micro-extraction) procedure was
followed for the samples collected at the base of Separator 3 and in the case of the
Cold Trap sample a hexane wash was used to obtain the samples and the samples
were analyzed using a direct liquid injection technique.
For the most part, the extracted flavor was dominated by the non-polar compound
limonene. In Test Series A, besides limonene, the main flavor extracted flavor
components were linalool, octanal and geranial. In Test Series B, besides
limonene, the main flavor extracted flavor components were ethyl butyrate,
valence and octanal.
For comparison, the distribution of these ten flavor components in 100% Valencia
orange juice is shown in Table 9.
[95] As shown, key orange flavor components were successfully isolated with the
porous substrates using supercritical fluid extraction.
[96] From an analysis of the data in the Tables above, one can determine the ratio of
the various flavor components as collected with the porous particles were
different with and without the use of the porous particles in collecting the
extracted flavors.
[97 Given the benefit of the above disclosure and description of exemplary
embodiments, it will be apparent to those skilled in the art that numerous
alternative and different embodiments are possible in keeping with the general
principles of the invention disclosed here. Those skilled in this art will recognize
that all such various modifications and alternative embodiments are within the
true scope and spirit of the invention. The appended claims are intended to cover
all such modifications and alternative embodiments. It should be understood that
the use of a singular indefinite or definite article (e.g., "a," "an," "the," etc.) in
this disclosure and in the following claims follows the traditional approach in
patents of meaning "at least one" unless in a particular instance it is clear from
context that the term is intended in that particular instance to mean specifically
one and only one. Likewise, the term "comprising" is open ended, not excluding
additional items, features, components, etc.
What is claimed is:
1. A process for recovering an extract from a mixture of an extraction fluid
and the extract, comprising:
a. contacting the mixture of the extraction fluid and the extract with a
contained volume of porous particles suitable for human consumption, the porous
particles having pores of a size which permits diffusion of extract into the porous
particles, and
b. changing a property of the extraction fluid so that extract deposits within
the pores of the porous particles.
2. The process of claim 1 wherein the porous particles have pores of a size
which permits diffusion of the mixture of extraction fluid and extract into the porous
particles.
3. The process of claim 1 for recovering an extract from a mixture of an
extraction fluid and the extract, wherein the mixture is recovered at an elevated pressure
from a supercritical fluid extraction, comprising:
a. contacting the elevated pressure mixture of the extraction fluid and the
extract with a contained volume of porous particles suitable for human
consumption, the porous particles having pores of a size which permits diffusion
of the extract into the porous particles;
b. changing the property of the mixture of the extraction fluid and the extract
so that extract deposits within the pores of the porous particles separate from
gaseous extraction fluid;
c. separating the gaseous extraction fluid from the porous particles, and
d. removing porous particles, containing deposited extract from the
contained volume.
4. The process of claim 4 wherein the porous particles have pores of a size
which permits diffusion of the mixture of extraction fluid and extract into the porous
particles.
5. The process of claim 2 wherein the changing of the property of the
mixture of the extraction fluid and the extract comprises reducing the pressure of the
mixture.
6. The process of claim 1wherein the extract is a fugitive extract.
7. The process of claim 6 wherein the fugitive extract is also an ingestible
extract and the porous particles containing the extract arc suitable for human
consumption.
8. The process of claim 3 wherein the extract is a fugitive extract.
9. The process of claim 8 wherein the fugitive extract is also an ingestible
extract and the porous particles containing the extract are suitable for human
consumption.
10. The process of claim 1 wherein the porous particles are porous silica
particles.
11. The process of claim 3 wherein the porous particles are porous silica
particles.
12. The process of claim 1 wherein the extract is selected from the group
consisting of aromas, flavors, flavor enhancers, aroma enhancers, taste enhancers,
antioxidants, vitamins, bioactives, functional ingredients, nutraceuticals, phytochemicals,
tastants, and natural colors.
13. The process of claim 3 wherein the extract is selected from the group
consisting of aromas, flavors, flavor enhancers, aroma enhancers, taste enhancers,
antioxidants, vitamins, bioactives, functional ingredients, nutraceuticals, phytochemicals,
tastants, and natural colors.
. The process of claim 1wherein the extraction fluid is carbon dioxide.
15. The process of claim 3 wherein the extraction fluid is carbon dioxide.
16. A process for recovering an extract from a plant material or an animal
material comprising:
(1) performing an extraction of the plant material or animal material using an
extraction fluid to produce an extract in admixture with the extraction fluid;
(2) contacting the mixture of the extraction fluid and the extract with a
contained volume of porous particles suitable for human consumption, the porous
particles having pores of a size which permits diffusion of extract into the porous
particles, and
(3) changing a property of the extraction fluid so that extract deposits within
the pores of the porous particles.
17. The process of claim 16 wherein the extraction is a supercritical fluid
extraction.
1 . The process of claim 1 wherein the plant material or animal material
contains residual moisture.
19. The process of claim 7 wherein the extraction fluid is supercritical
carbon dioxide.
20. The process of claim 17 wherein the porous particles are porous silica
particles.
21. The process of claim 20 wherein the extract is selected from the group
consisting of aromas, flavors, flavor enhancers, aroma enhancers, taste enhancers,
antioxidants, vitamins, bioactives, functional ingredients, nutraceuticals, phytochemicals,
tastants, and natural colors.