JPS5941691B2 - Method for producing decaffeinated vegetable material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION There has long been a considerable need for the production of decaffeinated plant materials, particularly beverages such as coffee and tea.

In the search for improved methods of manufacturing these decaffeinated products, a technique was invented that uses a caffeinated solvent consisting of a water-immiscible liquid fatty material.

This technology is based on Application No. 5 filed on November 27, 1974.
No. 27,870 and co-pending U.S. patent application Ser. No. 605,717 filed Aug. 18, 1975, both of which are fully incorporated herein by reference.

This technique involves contacting a liquid, water-immiscible fatty material with a caffeine-containing plant material, and keeping the fatty and plant materials in contact for a period of time sufficient to transfer the caffeine to the fatty material. and then separating the resulting caffeinated fatty material from the decaffeinated plant material.

This technique has wide application in decaffeination technology; virtually any form of plant material can be used.

For example, aqueous extracts of tea, green or roasted coffee beans can be decaffeinated.

Alternatively, solid plant material, including green or roasted coffee beans (preferably beans containing a total water content of about 20 to 60 parts by weight), is decaffeinated by direct contact with a liquid, water-immiscible fatty material. can be in.

The composition of the fatty material can also vary.

This material may be any animal, vegetable or synthetic oil or fat, admixture or fraction thereof which is in liquid form at the temperature of contact with the vegetable material.

This fatty material usually consists essentially of fatty acid esters (principally triclyceride esters) and can be used either in its original chemical form or in the form produced by customary processes known to those skilled in the art.

Examples of these fatty materials are safflower oil, soybean oil, corn oil, peanut oil, coffee oil, triolein, olive oil and lard.

The degree of decaffeination achieved by this technique can be varied as desired by modifying the contact conditions of the vegetable and fatty materials.

individual fatty materials, weight ratio of fatty materials to vegetable materials;
Temperature and contact time each have a direct effect on decaffeination efficiency.

In the decaf process, the caffeinated fatty material is usually regenerated.

By contacting the used and therefore caffeine-containing fatty material with water, its caffeine content is reduced.

The resulting aqueous solution can then be processed to recover the caffeine by-product and the fatty material recycled for further use in decaffeination.

Although this aqueous regeneration technique is effective, it has been found to have certain drawbacks.

It often slows down the overall decaffeination rate.

Also, handling and processing of the liquid medium and recovery of useful by-product components (especially caffeine) is tedious and expensive.

Additionally, some degradation of fatty materials occurs under processing conditions.

All these decomposition products are not always removed during the regeneration cycle and as a result their presence has a negative impact on the process.

The present invention relates to decaffeination of vegetable materials with recycled caffeine solvents consisting of liquid, water-immiscible fatty materials.

It is an object of the present invention to provide an improved regenerative process for caffeinated fatty materials used for decaffeination of vegetable materials.

In particular, it is desirable to extend the useful life of caffeinated solvents without compromising the flavor of the botanical material being decaffeinated.

Furthermore, the objects and advantages of the present invention will become clear from the following description.

According to the invention, a liquid, water-immiscible plant material is used to extract caffeine from the plant material.

After extraction, the caffeinated fatty material is recycled for further use by decaffeination by vaporization.

In this way the fatty material can be recycled in a continuous manner in an improved process for the decaffeination of vegetable materials.

A key factor in efficient and economical decaffeination is the use of caffeine recycling solvents.

In order to be able to be recycled, the fatty material used must be treated to reduce its caffeine content.

Otherwise its ability to decaffeinate the plant material will quickly deteriorate.

According to the invention, recirculation capability is achieved by subjecting the fatty material to two distinct separate treatment zones.

First, in the first decaffeinated zone, the fatty material picks up caffeine from the vegetable material it comes in contact with.

The resulting caffeine-containing material is then transferred to a second regeneration zone.

The caffeine is then removed by vaporization.

After this second treatment, the fatty material can be returned to the second zone for further decaffeination use.

Suitable conditions and treatments for the decaffeinated zone are those previously described in the cited co-pending application.

Any changes according to the invention are either routine modifications or improved results through the use of fatty materials that have been subjected to the exigencies of regeneration.

Under normal conditions of operation, the caffeine content of the fatty material used to decaffeinate the vegetable material can vary widely.

However, at high concentrations of caffeine its solvent capacity decreases.

Therefore about 10,000pp! 11 or less, preferably maintained at about 2,000 to 5,000 pIXn.

Regeneration involves the removal of at least some of this caffeine from the fatty material.

But you don't need all caffeine removal.

About 1,000 p1N11 or less, preferably about 50 to 200
1) As long as the caffeine content of the fatty material in I)m is obtained, the whole process proceeds smoothly and efficiently.

In the regeneration zone, vaporization of caffeine is usually carried out in a continuous manner after each cyclical contact of fatty material and vegetable material.

But this is not necessary. Regeneration can be carried out in batch fashion, for example.

A volume of caffeinated plant material can thus be collected, regenerated and then returned to the decaffeinated zone.

In another embodiment, only a portion of the caffeinated fatty material is regenerated in any given cycle.

Regeneration of caffeine-containing fatty materials can be achieved under various conditions.

A threshold requirement for this process is that the temperature and pressure to which the caffeine-containing fatty material is exposed is adequate for the vaporization of the caffeine, such as about 170° C. at atmospheric pressure.

However, conditions above the minimum threshold are preferably used to increase the rate of caffeine vaporization.

This increase occurs at high temperatures and/or low pressures.

However, extreme changes should be avoided.

Regeneration at very low pressures can, for example, proceed with some loss of efficiency.

The mechanical discharge limit is such that the lowest absolute pressure can be maintained during vaporization even though the rate of decaffeination is reduced.

It is the fatty materials that are affected as the vaporization temperature increases.

These fatty materials - especially if they contain water and/or non-caffeinated plant material components and other dissolved impurities - exhibit an increased rate of decomposition at elevated temperatures.

It is therefore desirable to minimize this effect and to use vaporization conditions that result in efficient one-way caffeine removal.

Therefore, the regeneration of fatty materials is at 50-450°C and at 760°C.
It occurs at corresponding pressures of WHg or less, but is usually carried out at 150-350°C and 100-0.01 aHg pressure.

More preferred conditions for vaporization include a temperature of 150 to 250°C and a pressure of 15 to 0.17 NII Hg.

The regeneration temperature is usually above the temperature at which decaffeination occurs (usually 0
~150'C, 0 for aqueous extracts of plant material
~50°C and 30-150 for solid vegetable material
C), it is often desirable to heat the caffeine-containing fatty material before entering the regeneration zone and to cool it after the fatty material is discharged.

These steps can be carried out in a manner known to those skilled in the art - such as in conventional aesthetic heat exchangers.

They are particularly desirable as they avoid the need to heat the fatty material in the regeneration zone before vaporization of the caffeine can occur.

Similarly, rapid cooling after regeneration minimizes degradation of fatty materials.

Another factor that greatly influences the efficiency of regeneration is the form of the caffeine-containing fatty material during processing.

A thin film of caffeinated fatty material greatly accelerates the rate of caffeine removal.

Furthermore, this acceleration reduces the time that fatty materials are exposed to high decomposition temperatures.

It is therefore also a means of preserving fatty materials.

Usually a film thickness of less than about 20 inches of caffeine-containing fatty material, more preferably less than 3 inches, should be used during vaporization.

Most preferably, the thickness of the caffeine-containing fatty material is less than 171 g.

Several methods are available to obtain thin films.

On a commercial scale, for example, falling film
lling film) and wiped film (w
iped film) equipment has been used to produce such films for a variety of applications.

However, the use of packaging columns is highly preferred.

They represent a simple method of forming these large area thin films and are particularly easy to prepare and maintain vaporization temperatures and pressures.

The time that the fatty material is exposed to sufficient temperature and pressure to vaporize portions governs the efficiency of decaffeination.

Under any of the above conditions, substantial caffeine removal from the fatty material can be achieved by about 1 to 4 hours.

However, some decomposition of the fatty material may occur within such a period of time, especially if the temperature is high enough to reach 150°C.
It can happen if there is more than that.

Therefore, about 0.3 to 20 minutes, preferably 0.5 to 20 minutes.
5 minutes residence time (i.e. time of exposure to regenerative vaporization conditions)
It is preferable to use

By operation of simultaneous use of high temperature, low pressure and thin film thickness as described above, substantially 100% of
% decaffeination can be achieved even within these very short residence times.

It has also been discovered that the regeneration efficiency of caffeine-containing fatty materials can be improved by passing a carrier or sweep gas (5Weep gas) over and/or through the fatty material.

The effect of the gaseous caffeine solute in cases where a carrier gas such as nitrogen or preferably water vapor (as it condenses more easily and thus helps maintain low pressure in the regeneration zone) rapidly sweeps through the fatty material. Target removal rate is greatly increased.

Bulk carrier gas can be used if regeneration is performed at or near atmospheric pressure.

However, if a vacuum is used, a correspondingly lower amount of gas is required for the same effect.

The optimum amount of gas depends on the free space or volume surrounding the fatty material and occupied by the gas volatilized from the fatty material.

Since the function and mechanism of carrier gases are well known, determining the optimal amount to increase the rate of caffeine sublimation is easily determined.

Because of the conditions conducted during this process, the fatty material undergoes some degradation - the amount being largely determined by the severity and time of the revaporization conditions.

In particular, fatty acid triglycerides, of which the fatty material is originally composed, liberate and hydrolyze free fatty acids.

Other decomposition products produced within fatty materials are numerous oxidation products.

These oxidation products - especially aldehydes - are responsible for at least some of the off-flavors and rancidities that are naturally common in fatty materials.

A high content of these free fatty acids and other degradation products within fatty materials is undesirable.

Their presence can alter the solvent properties of the fatty material and/or contaminate the vegetable material.

However, it has also been discovered that these harmful impurities are removed during caffeine vaporization.

This simultaneous removal of impurities from the fatty material during regeneration substantially extends the time that the fatty material is available within the decaffeination process.

In fact, exposure to caffeine vaporization conditions completely purifies the fatty material with undesirable constituents, so that instead of replacing the used fatty material weekly or often with new one, in effect the decaffeinated fatty material solvent is removed. Endless uses are possible.

Occasional addition of fresh fatty material is desirable; this is to compensate for the small amount of fatty material that is added during the process.

This ensures a substantially constant amount of recycled fatty material.

It has also been discovered that this purifying effect is desirable as a pretreatment for new fatty materials.

Preferably, the fresh caffeine solvent is subjected to regenerative vaporization conditions (even if it does not contain any caffeine) prior to initial contact with the caffeine-containing botanical material.

This preliminary purification of the fatty material can be accomplished in a separate vaporizer, but the used caffeinated solvent is recycled - i.e. added at a point in the cycle in the decaffeination band and before the regeneration band. This is also conveniently accomplished by adding fresh replenishment of fatty material to the mixture.

In this method, the fresh fatty material does not come into contact with the vegetable material until it has passed at least once through a regeneration zone where it is purified under vaporizing conditions.

Additionally, additional pre-purification of fatty materials can be performed before addition to the recycled solvent.

Depending on the source of the fatty material, it may contain various non-glyceride components that decompose under the conditions used in the method.

Preliminary removal of these components therefore prevents their introduction into the system and avoids their formation within the solvent itself - especially if their decomposition products are non-volatile under vaporization conditions.

Further removal of these non-glyceride components from the fatty material can be easily accomplished, for example, by contacting the fatty material with an absorbent.

Absorbents such as activated carbon have virtually no affinity for the triglyceride content of fatty materials, but facilitate other compounds to produce decaffeinated solvents with improved stability and purity. to be removed.

It is desirable to remove moisture from caffeine-containing fatty materials as described in the above-identified patent application Ser. No. 605,717 coupled with the regeneration removal of caffeine.

This removal is easily accomplished under temperature and pressure conditions to vaporize the caffeine in the regeneration zone.

However, in preferred embodiments, water is separately removed from the caffeine-carrying fatty material.

Evaporation of water in the regeneration zone can make it difficult to maintain and/or induce turbulence that transfers fatty materials into the steam.

It is therefore desirable to remove at least a substantial portion of the water from the caffeine-containing fatty material prior to exposure to caffeine vaporizing conditions, such as by crush distillation in conventional equipment.

The regenerated fatty material (usually after cooling to a suitable temperature) is recycled to the decaffeination zone for further contact with the caffeinated plant material.

No additional processing is required.

However, it is often desirable to initially add a small amount of water, also as described in US Application No. 605.717.

In decaffeinating solid vegetable materials, high efficiency is obtained when the solid materials contain about 20 to 60 parts by weight water.

However, contacting such solid materials with substantially anhydrous fatty materials reduces this moisture content.

Therefore, if the solid material is decaffeinated, 0.9
It is preferred to add ~1.2% water to the fatty material, preferably about 1 part by weight.

This amount acts to maintain the aqueous content of the solid vegetable material and maintain optimal decaffeination efficiency.

Caffeine removal according to the present invention allows for an improved method of recovering valuable amounts of caffeine by-products.

The vapors removed during regeneration are easily recondensed from the gaseous form by cooling in a conventional condenser.

Thus, in contrast to, for example, techniques in which the caffeine-containing fatty material is regenerated by extraction with water (caffeine and other solubles are transferred to the aqueous phase), no multi-stage recovery process is required.

The invention allows easy recovery of the materials removed from fatty materials - including caffeine.

Many variations of the process or materials involved in the method are possible without departing from the scope of the invention.

However, these variations are largely conventional and therefore often lack specificity.

In the following examples, which are detailed explanations of the invention, references are by weight unless otherwise specified.

Example 1 Green coffee beans were decaffeinated with coffee oil in a zone consisting of a four-chamber countercurrent extraction system.

Each chamber (or chamber) was filled with beans having a moisture content of 6.8 to 9 parts by dry weight and about 45 parts by total weight.

The coffee oil passing through the chamber was maintained at 105°C during decaffeination.

A total oil to bean weight ratio of 10:1 was used and the extraction was carried out over a linear extraction time of 8 hours (2 hours each cycle).

After passing through the decaffeination zone, the recycled oil passed through a flash distillation zone to continuously remove water, a heater that raised the temperature to 180°C, a regeneration zone, and then a cooler that returned the temperature to 105°C.

After passing through the cooler, one part by weight of water was injected into the oil just before returning to the countercurrent extraction zone.

The regeneration zone consisted of a jacketed column with a height of 2 m% and a diameter of 15 cIrL.

It has an internal volume of approximately 0.033 m3, of which 93 sections are free volume, and the remaining sections are pile ring (pail ring).
) is the volume occupied by packaging material.

The packaging column has a jacket temperature of 210 °C and 2,2
ffHg pressure was maintained.

Since the oil was monitored at the top of the column, 18f of the oil I Ky was injected into the bottom of the column.

The injected water vapor and vapors from the oil passed through an outlet at the top of the column and were condensed in a collection chamber maintained at 30°C.

The calculated film thickness and oil residence time in the packaging column were 0.2 layers and 158 minutes.

In the regeneration zone, the caffeine content of the fatty material is 34
00p11+11 to about 170pI) m? The number has decreased.

Thus, the regeneration efficiency of the caffeine-containing fatty material is approximately 95
He was in charge.

This resulted in an overall efficiency of 97 for removing caffeine from green beans.

The vapor condensed in the collection chamber was analyzed.

It consisted primarily of caffeine, water and a fatty acid mixture.

Example 2 Caffeinated coffee oil removed from the extraction system of Example 1 was subjected to sublimation conditions in a wiped film evaporator.

The evaporator consisted of a 5 crrt diameter glass evaporator tube with a wet film surface area of approximately 32 mm.

Four Teflon blades rotated at high speed inside the tube to maintain an oil film thickness of 1-2 layers.

The evaporation column and feed flask were electrically heated to maintain the oil at the same temperature.

A condenser within the evaporator tube was maintained at approximately 50°C to condense the caffeine vapor removed from the oil.

A mechanical pump with a condenser unit was used to obtain subatmospheric pressure.

A series of regeneration tests using a wiped film evaporator were conducted with an oil feed rate of approximately 3.2 ml 7 minutes.

The results of these tests - for a single pass of oil through the column - showed that regeneration at atmospheric pressure requires a temperature of about 260'G to achieve a regeneration efficiency of 75 degrees.

When the pressure in the column was reduced to 500 microns IJ and 100 microns Hg, the temperatures required for this efficiency dropped to 1900.150° and 90° C., respectively.

Example 3 Corn oil used to decaffeinate an aqueous 0-st coffee extract was used in a series of tests to determine the effect of film thickness on regeneration efficiency.

A film of corn oil - containing about 100 g of caffeine - was heated to a predetermined vaporization temperature at atmospheric pressure.

A nitrogen sweep gas was passed continuously into and over the surface of the film to remove caffeine vapors.

The test conditions and results were as follows: These results show a dramatic increase in caffeine vaporization efficiency achieved with thinner films.

Claims (1)

Claims: 1. Extraction of caffeine-containing plant material with a large quantity of water-immiscible recirculating liquid fatty material in a decaffeination zone, which extraction transfers caffeine from the plant material to the fatty material. The caffeine-containing fatty material produced by the extraction is separated from the plant material and transferred to a regeneration zone to remove the caffeine before being recycled to the decaffeination zone. A method for producing a decaffeinated vegetable material, characterized in that decaffeinated plant material is removed by vaporization in a regeneration zone. 2. The method of claim 1, wherein the caffeine-containing plant material is selected from the group consisting of green coffee solids, roasted coffee solids, and tea, aqueous extracts of green coffee and roast coffee. 3 Water-immiscible liquid fatty materials include safflower oil, soybean oil,
a first selected from the group consisting of corn oil, peanut oil, coffee oil, triolein, olive oil and lard;
The method described in section. 4 Caffeine at a temperature of 50-450℃ and 760m
2. The method of claim 1, wherein the removal is carried out under conditions comprising an Hg pressure of up to . 5. The method of claim 4, wherein caffeine is removed from a film of fatty material having a thickness of up to 20w1. 6. The method of item 5, wherein the caffeine-containing fatty material is placed in open aeration conditions for up to about 4 hours. 7. The method of claim 6, wherein the carrier gas is passed over the caffeinated fatty material to increase the rate of caffeine removal. 8 Caffeine at a temperature of 150-350℃ and 100℃
The first removed under conditions consisting of ~0.017'aHg pressure.
The method described in section. 9. The method of claim 8, wherein caffeine is removed from a film of fatty material having a thickness of up to about 3 inches. 10. The method of item 9, wherein the caffeine-containing fatty material is subjected to vaporizing conditions for about 0.3 to 20 minutes. 11. The method of claim 10, wherein the carrier gas is passed over the caffeinated fatty material to increase the rate of caffeine removal. 12 Caffeine is heated at a temperature of 150-250°C and 15
2. The method of claim 1, wherein the removal is carried out under conditions consisting of ~0.1'//l; III Hg pressure. 13. The method of claim 12, wherein caffeine is removed from a film of fatty material having a thickness of up to im. 14. The method of paragraph 13, wherein the caffeine-containing fatty material is subjected to vaporizing conditions for about 0.5 to 5 minutes. 15. The method of clause 14, wherein the carrier gas is passed over the caffeinated fatty material to increase the rate of caffeine removal. 16. The method of claim 15, wherein the carrier gas comprises water vapor. 17. The method of claim 15, wherein the caffeine-containing plant material comprises green coffee beans having a moisture content of about 20-60% by weight. 18. The method of claim 1, wherein the caffeine-containing plant material comprises green coffee beans having a water content of about 20-60% by weight. 19. The method of claim 18, wherein about 0.9 to 1.2 parts by weight of water is mixed with the regenerated fatty material before being recycled to the decaffeinated zone. 20. The method of claim 1, wherein the volume of recycled fatty material is maintained at a substantially constant volume by adding fresh fatty material to the caffeine-containing fatty material during the process.