JPS5941378B2 - Method for decaffeinating a caffein-containing aqueous extract - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for decaffeinating aqueous extracts of botanical materials.

There has long been a considerable demand for decaffeinated plant materials, especially beverages such as coffee and tea.

Conventional prior art techniques for decaffeination generally involve the use of tritalol or chloroformin organic solvents, which are contacted with either the botanical materials or their aqueous extracts.

When sufficient caffeine has been transferred to the solvent, the resulting caffeine solution is separated for further processing of the decaffeinated material or extract.

Among others, the use of fatty materials for the removal of caffeine from aqueous caffeine-containing extracts is described in German Patent Application No. 254.
No. 8916.

Briefly, this technique involves contacting a fatty material that is miscible with liquid water with an aqueous extract of a botanical material and maintaining these fluids in contact for a sufficient period of time to approach or reach a partitioning equilibrium for caffeine. Next, it is capable of separating the two liquids.

Due to this sequence, the caffeine initially present in the aqueous extract is partially transferred to the fatty material.

When the caffeine-containing fatty material is then separated,
The extract shows a corresponding decrease in the concentration of caffeine.

However, according to the present invention, the use of high temperatures during the contacting of the fatty material and the aqueous extract not only substantially improves the decaffeination efficiency (but also the expected opposite effect). Do not cause

Advantageously, the high partition coefficient of caffeine and the very easy separation of the two immiscible liquids into separate phases is advantageous if these liquids are kept at high temperatures during the contact period and then separated into their respective phases. can be achieved.

In this way, one liquid can be included in another liquid, resulting in a liquid quantity of one liquid being retained in another liquid phase. -Entrainment is reduced or avoided.

[The term inclusion 1 refers to the phenomenon in which one liquid is substantially uniformly dispersed in another liquid phase in a gel-like form.

Although less stable than emulsions, such migrations usually require additional steps to separate or dissolve them.

The present invention comprises: (a) contacting an aqueous extract of a caffeine-containing botanical material with a liquid water-immiscible fatty material; (b) converting the aqueous extract and the fatty material from the aqueous extract to the fatty material; maintaining the contact for a sufficient time to transfer the caffeine; and (e) separating the caffeine-containing fatty material from the aqueous extract, wherein the liquid fatty material and the aqueous extract are separated from their contact center (both about 65°C or so.

A method for decaffeinating a caffeinated aqueous extract of plant material comprising:

As used herein, "fatty material" means any animal or vegetable fat or oil or mixture or fraction thereof that is liquid at a temperature of about 65°C (and above).

These fatty materials usually consist essentially of fatty acid esters (usually glycerol esters) and can be used either in their native form or as products of customary processing known to those skilled in the art.

Desirably the fatty material is substantially a non-solvent for the non-caffeine components of the vegetable material.

For example, fatty materials may be unsaturated or saturated fats or oils.

Similarly, unrefined or conventionally refined oils, as well as oils with or without conventional additives such as antioxidants and preservatives, are within the scope of the invention.

However, it is desirable that the fatty material be substantially free of natural or added surfactants.

These materials stabilize the emulsion that forms when stirring the liquid fatty material and the aqueous extract, thereby increasing the difficulty of processes such as liquid-liquid separation.

Particularly preferred are edible fatty materials including, for example, safflower oil, soybean oil, corn oil, peanut oil, olive oil, coffee oil, triolein (an ophic acid ester of glycerol), and wood.

The caffeinated extracts to be decaffeinated according to the invention are aqueous extracts of plant materials such as roast coffee, green coffee and tea.

For roast coffee and tea blending, the solubles remaining in the extract after decaffeination are further processed to provide a beverage product.

In green coffee, an aqueous solution HV is used to selectively remove caffeine from green beans.

A preferred extraction of caffeine from green beans can be carried out using closed aqueous recirculation, for example, in the manner described in Veri et al., US Pat. No. 2,309,092.

The disclosure is incorporated herein by reference to describe the method.

The aqueous extract is then decaffeinated itself with a fatty material, and the decaffeinated green beans are converted into an edible beverage product, such as during subsequent roasting.

Extracts of botanical materials such as roasted coffee or tea containing sensitive volatile fungi are preferably processed to avoid losses.

Therefore, prior to decaffeination, by stripping the fresh extract, for example with steam, suitably according to known techniques,
It is desirable to isolate volatile flavors.

The isolated volatiles can be returned to the extract or product in a later step.

Caffeine transfer from aqueous extracts of plant materials to fatty materials depends in part on the caffeine partition coefficient between the two liquids.

Caffeine partition coefficient values vary with the particular liquid and associated conditions.

It reflects the relative affinities of fatty materials and aqueous extracts for caffeine and is defined by a linear equilibrium relationship: The relative amounts of the two liquids together with the partition coefficient adjust the total weight of caffeine transferred between them. do.

According to the present invention, caffeine transfer occurs at elevated temperatures of about 65°C or higher.

It has been found that the extracted coffee and tea flavor components are sufficiently stable at temperatures above 65°C and can be maintained for up to about 3 hours, although less than about 1 hour is preferred.

The advantages of the invention are further increased at high temperatures, where correspondingly shorter treatment times can also be used.

Substantially no benefit is obtained by maintaining the two liquids at temperatures above about 150°C.

Temperatures in the range of about 65-150°C are therefore preferred.

Once the aqueous extract is separated from the fat phase, the aqueous phase is)
It is then dried or cooled, suitably below about 30°C, if possible immediately to prevent V-bur loss and decomposition.

It is unnecessary to subject the aqueous extract and fatty material to such high temperatures before they remain in contact and are then separated.

For example, they can be contacted at low temperatures. It can then be heated to this range.

Similarly, for example, an extract at low temperature can be contacted with a fatty material of sufficient temperature to bring both liquids within the desired temperature range during their contact time.

Previous studies have shown that temperature affects the distribution coefficient of caffeine.

For example, in the same German application mentioned above, partition coefficients are given for various temperatures.

However, the relationship shown therein is only for temperatures of 20° C. and below, and the partition coefficient at these temperatures can increase or decrease with temperature depending on the particular fatty material used.

However, at the high temperatures of the present invention, a substantially larger difference was observed, with the caffeine partition coefficient always increasing.

A significant increase in the rate of caffeine transfer from the aqueous extract to the fatty material substantially improves the efficiency of the decaffeination process.

The caffeine concentration of the initial caffeinated fatty material increases rapidly and approaches its equilibrium value.

Although a contact time of at least 2 minutes is preferred when operating on an industrial scale, liquid-liquid contact times as short as a few seconds are preferred.

Appropriate upper limits for the temperature and time of contact of the fatty material with the aqueous extract can be readily determined by one of ordinary skill in the art having regard to the mechanical means used to maintain and then separate the two liquids.

For example, if a high degree of decaffeination is desired by multi-step mixing of the extract and the fatty material, one repeated contacting and separation step can consume a substantial amount of processing time.

On the other hand. Countercurrent extraction column or very large number of theoretical columns
A single-step caffeine technique utilizing a single-step or similar device with several steps can significantly reduce overall processing time.

In an efficient treatment method requiring short-term contact, for example, about 15
0°C (if the temperature exceeds 100°C).

Suitable conditions above atmospheric pressure as well as temperatures (necessary to maintain the material in liquid form) can be used.

However, temperatures of about 75-120°C are usually preferred.

Temperatures of about 85 to about 100°C are even more preferred and do not require pressure to maintain the fatty material and aqueous extract in liquid form.

Related to the above description, there is another factor that affects decaffeination efficiency.
One factor is the soluble solids concentration of the aqueous extract.

Increasing the solids concentration of the aqueous extract reduces its tendency to form emulsions with fatty materials.

For example, it has been found that at an extraction concentration of 45 weight candy soluble solids, emulsion formation problems that can interfere with the separation of fatty materials from the aqueous extract are significantly reduced or eliminated.

Furthermore, such emulsions that can be formed during decaffeination of such high solids extracts have substantially reduced stability.

The two liquids can therefore be easily separated into different phases using conventional techniques.

Particularly at high extract concentrations, higher inclusions as opposed to emulsion formation can occur upon intimate mixing of aqueous extract and fatty material.

Therefore, extract concentrations greater than about 55 times maximum are preferably avoided.

However, this does not mean that even higher extraction concentrations cannot be carried out.

Concentrations up to about 70 parts can be used, especially at the highest temperatures of the present invention.

It is understood that the inclusions that can occur at such concentrations can be easily overcome by subjecting the separated phase of at least the fatty material (and preferably also the aqueous extract) to a simple purification step such as centrifugation. understood.

This purification of the separate phase can normally be carried out after the extract has reached the ultimate desired degree of decaffeination (usually about 97% for coffee, for example).

Alternatively, the extract and one or fatty materials can be purified from the inclusion fluid after any decaffeinating episode or each decaffeinating cycle.

Therefore, it is preferred that the concentration of soluble solids in the aqueous extract of the plant material is within the range of about 30-70%.

However, it is also preferred that a concentration of about 35 to 55 φ is used to maximize caffeine removal efficiency and minimize inclusion effects.

The effects of contact temperature and solids concentration of the aqueous extract are correlated.

Aqueous extracts with concentrations above about 40% (with some variation depending on the particular type or mixture of botanical materials being extracted) are more difficult to extract at ambient temperature.

For example, an ambient temperature aqueous extract of roast coffee with a solids concentration of about 40% has a viscosity and surface tension that becomes precluded from intimate mixing with fatty materials.

However, it has been found that the high temperature of decaffeination of the present invention achieves efficient mixing and decaffeination of the extract.

In addition to other benefits achieved by the use of high temperatures in the present invention, it facilitates the physical properties of rapidly and quantitatively transferring caffeine from the extract to the fatty material.

An additional advantage of the present invention is increased processing flexibility.

The high extractable solids concentration liquids described herein are particularly preferred when used at elevated temperatures.

Contacting the fatty material and the aqueous extract.

It is possible to use more efficient methods.

The tendency of these liquids to form stable emulsions is reduced.

Stirring or similar methods can be improved to bring the liquids into more intimate contact, thereby increasing the decaffeination rate without correspondingly significant detriment to ease of separation.

In a preferred embodiment of the invention, for the production of decaffeinated extracts of roast coffee, the aqueous extract contains a low amount of total soluble solids (approximately 5 times maximum).

More preferably, it has a low caffeine content (equal to about 6 times maximum).

Extracts having such caffeine content are prepared at relatively low temperatures, typically not exceeding about 120°C, e.g. 90°C.
It is advantageously produced by extracting coffee with an aqueous medium at a temperature in the range from 120<0>C.

At these temperatures all the caffeine contained in the non-caffeinated solids is extracted, so the caffeine content of the total extracted solids becomes thicker.

Preferably, the extract is concentrated to a higher content of soluble solids prior to decaffeination.

In practice, however, the coffee can be subjected to a second extraction at a high temperature, preferably at a low temperature (at least about 140°C).

The second extract can then be added to the cold decaffeinated extract, preferably after concentration.

In this way, decaffeinated extracts of customary composition can be produced even if only their constituent parts are decaffeinated.

Additionally, optional embodiments of the invention include stripping the extract of non-caffeine compounds from the separated caffeinated fatty material.

The fatty caffeine solvent used in the present invention is substantially selective for caffeine, but is capable of removing small amounts of other components of the botanical material from the aqueous extract.

Some of these components merit recovery for subsequent return to the decaffeinated extract.

Caffeine solvent stripping of volatile hum-bar from the fatty material can be an alternative or addition to the already discussed preferred pre-treatment of the aqueous extract for the removal of volatile hum-bar.

Generally only in decaffeination of tea extracts. The fatty material contains non-volatile fumes that are worth recovering.

Stripping of the extracted components from the separated fatty material can be accomplished under conditions of temperature and pressure sufficient to selectively volatilize the fatty material.

Preferred conditions for stripping are about 85 DEG to about 125 DEG C. and a corresponding pressure of about 1 to about 150 mffl Hg.

These conditions allow the Hun-Bar components to be separated and then collected as by vertical compaction.

The invention is illustrated by the following columns, and unless otherwise specified, cracks and percentages are by weight.

Row 1 An aqueous extract of roasted ground coffee beans produced at an extraction temperature of up to 160° C. and having a soluble solids concentration of 17% is stripped with steam to remove volatile fungi.

Then, the IJ whelk extract was vacuum evaporated to 45.8
Increase the solids concentration to the maximum.

The extract is then introduced into a decaffeination system.

The decaffeination system consists of six consecutively connected steps.
Does each process involve only one corn? The mixer consisted of a static alignment mixer for contacting the liquid and extract, connected to a jacketed vertical holding column that separated these mixtures by gravity.

This system consists of countercurrent passage of fatty material and extract streams.

Introducing new extracts and new fatty materials into the system,
The caffeinated fatty material and decaffeinated extract are recovered from the system.

Appropriate pumps, piping and valves are provided.

The extract (at 90 °C) was fed into the mixer at 120 g for 1 min, and the corn oil (at a temperature of 90 °C) was fed at 1 min for 1 min.
．． Feed 7 yu to the mixer.

The residence time of the extract in the decaffeinated system after the operation reaches a steady state is about 45 minutes.

The extract was mixed with the fatty material in each static mixer for approximately 2 minutes.

Maintain at about 90° C. while stabilizing in the separation column for about 5 minutes.

The extract exiting the decaffeinated system is analyzed.

It shows a caffeine content less than 1 with 3φ of the first extract.

After re-addition of the volatile fungi that was stripped before decaffeination, the extract is spray dried to produce instant coffee powder.

When reconstituted with water, this powder provides a decaffeinated beverage that differs in flavor from commercially available products.

Row 2 The strip extract of Row 1 is concentrated by vacuum evaporation to a soluble solids concentration of 455 parts by weight.

The decaffeination system consists of a vertical countercurrent extraction column with an interior consisting of a horizontal circular column (v-) fixed to a reciprocating vertical shaft.

This column has a length of 2.2 m u and a column and a
- It has an inner diameter of 5 degrees.

Coffee at 90° C. is fed to the bottom of the column at a feed rate of 445 c, c-/min.

The 90° C. extract is fed to the top of the column at a rate of 30 cmc/min to a weight ratio of 15:1 for the oil seal extract.

i After the operation of the column reaches a constant state, the extract leaving the bottom of the column is centrifuged to remove the oil content.

Separation of the centrifuged extract shows a degree of decaffeination of about 97 degrees.

The extract is then separated from the volatile feces before decaffeination.
Recombine with bar and spray dry.

When constructed with water, the resulting beverage was virtually identical to the commercial product.

Example 3 The effect of aqueous extract solids concentration and temperature on decaffeination is illustrated in the following table.

One part by weight of the extract containing the indicated concentration of soluble solids is placed in a separatory funnel and 15 parts by weight of corn oil are added.

Materials are at designated temperature.

Each funnel is shaken 20 times at 40 second intervals and immersed in a water bath maintained at the same temperature.

The funnel is kept in the bath for 1 hour to ensure separation of the two liquid phases.

The ease and efficiency of separation of the two phases is reflected in the time required for the appearance of different interfaces between the two liquids, in visual inspection of the emulsion, and in thin layer chromatography of the emulsion.

The results are shown in the following table: Table 1 -h Extract Temperature Separation time Summary Solid concentration 5.5% 20°C 35-45 minutes.

Shore 5.5 section 90℃ 4-6 minutes - 17 section 20℃ 45-55 minutes - 17th 90'C 4-5 minutes - 30φ 20℃ 35-40 minutes - 30 section 90℃ 4-5 minutes - Substantially "9% 20℃°0-35 minutes Including 49% 90℃ 3-4 minutes - -- E = Knee extraction humidity temperature Separation time Summary Solid concentration 64 times 20℃ 8-12 minutes Including 64 times 90 degrees Celsius 3-4 minutes 5 minutes included 1) Roasted ground coffee extract has an initial temperature of 170℃
It was produced by countercurrent extraction utilizing a water stream at a temperature of approximately 100°C and a final temperature of approximately 100°C.

The extract was then diluted as desired or concentrated by vacuum evaporation to reach the indicated solids concentration.

Table 22) ” -t==--Extract Part Degree Separation Time Summary Solid Concentration Emul 5% 20℃ 30-35 minutes John 5% 90℃ 4-6 minutes - 30 Section 20℃ 35-45 minutes -30 Section 9
0℃ 4 to 5 minutes - 44 units 20℃ 30 to 35 minutes included 44 units 90℃ 3 to 4 minutes - 2) Roasted ground coffee extract has an initial temperature of about 11
It was prepared by countercurrent extraction using a water stream at 0°C and a final temperature of 100°C.

The extracts were then diluted or concentrated by vacuum evaporation.

Table 33) 1 = -1 = Knee Extract Temperature Separation Time Summary Solids Concentration Substantially 21% 2o-C 45-60 minutes included Substantially Emulsion Substantially 21% 90'.

5 to 6 minutes included, small emulsion, practically 42 pieces, 20℃, 18 to 22 sachets, store 42%
90°C for 3-4 minutes.3) Green coffee bean extract was prepared using a constant temperature water stream at 100°C, and the extract was concentrated by vacuum evaporation.

Table 44) Tea extract solid concentration Temperature Separation time Summary 14% 2
0℃ 25-30 minutes - 14% 90℃ 4-5 minutes - 42φ 20℃ 16-20 minutes High inclusion 42 section 9
0°C 3-4 minutes Inclusion In each sample at 20°C, the separated oil phase has a clarady appearance, indicating some inclusion of extractives.

4) Tea extract was prepared using a constant temperature water stream at 115°C.

The extract was concentrated by vacuum evaporation. Example 4 The method of Example 3 was repeated with other fatty materials.

The weight ratio of Yufu extract is 1521, and the solid content of the aqueous extract of roasted ground coffee is 30%.

Table 55) Fatty ingredients Temperature Separation time Required Olive oil
20℃ 25-43 minutes Low inclusion olive oil 90℃
1-2 minutes - Safflower oil 20℃ 18-32 minutes Low inclusion safflower oil 90℃ 1-2 minutes - Mixed oil (7”-=?-500) 20℃ 26-36 minutes
Low package name mixed oil (Darky 500) 900 2-3 minutes -5)
Roasted ground coffee extract was prepared by countercurrent extraction using a water stream with an initial temperature of 160°C and a final temperature of about 100°C and then concentrated.

Example 5 Caffeine partition coefficients at various temperatures are determined using an aqueous extract of roasted ground coffee containing corn oil and 50% candy solubles.

This is accomplished by mixing oil and extract in a 20:1 weight ratio in a bomb.

The bomb was then heated to the indicated temperature (and 1
(pressure above atmospheric pressure relative to 15°C).

The results are shown in the table below. Table 66) Temperature Decaffeinated Partition Coefficient 20℃
31 candy 0.02250℃
47φ 0.04390℃
64% 0.091115℃
68% 0.142 In the previous example, vacuum evaporation of the extract can be replaced by other concentration methods such as freeze concentration.

Similarly, spray drying can be replaced by freeze drying or other suitable drying techniques.

6) Roasted ground coffee extract has an initial temperature of 160℃
℃, prepared by countercurrent extraction using a water stream with a final temperature of about 100 ℃, and then concentrated.

Claims (1)

Claims: 1. A method for decaffeinating an aqueous extract of a caffeine-containing botanical material. (a) contacting the aqueous extract with a liquid water-immiscible fatty material; and (b) maintaining contact between the aqueous extract and the fatty material. transferring the caffeine from the aqueous extract to the fatty material and (.) separating the caffeine-containing fatty material from the aqueous extract, in which case the liquid fatty material is separated, in which case the liquid fatty material and the aqueous extract Objects remain in contact for a short period of time (approximately 65
℃ or about 65℃. The above decaffeination method. 2. The method of claim 1, wherein the aqueous extract has a soluble solids concentration of 30 to 70% by weight. 3. The method of claim 2, wherein the aqueous extract has a soluble solids concentration of 35 to 55% by weight. 4. A method according to any preceding clause, wherein the liquid fatty material and the aqueous extract are or are brought to a temperature of about 75-120<0>C while maintaining contact. 5. The method of claim 4, wherein the liquid fatty material and the aqueous extract are or are brought to a temperature of about 85-100<0>C while maintaining contact. 6. A method according to any preceding clause, wherein the fatty material is selected from the group consisting of safflower oil, soybean oil, corn oil, peanut oil, olive oil, coffee oil, triolein and lard. 7. The method according to any of the above items, wherein the aqueous extract is an extract of tea or roast coffee. 8. The method of claim 7, wherein volatiles are stripped from the aqueous extract prior to contacting with the fatty material. 9. Aqueous extracts of roast coffee contain a small amount of total soluble solids (both with a caffeine content equal to 5 parts by weight).
or the method described in Section 8. 10. The method of claim 9, wherein the aqueous extract is prepared by extracting roast coffee at a temperature not exceeding about 120°C. 11. The method according to any one of items 1 to 6, wherein the aqueous extract is from green beans.