CA1097533A - Process for manufacture of "mild coffee" - Google Patents
Process for manufacture of "mild coffee"Info
- Publication number
- CA1097533A CA1097533A CA264,008A CA264008A CA1097533A CA 1097533 A CA1097533 A CA 1097533A CA 264008 A CA264008 A CA 264008A CA 1097533 A CA1097533 A CA 1097533A
- Authority
- CA
- Canada
- Prior art keywords
- beans
- solvent
- coffee
- green
- process according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
Title: Process for manufacture of "Mild coffee".
Abstract of the Disclosure Green coffee beans are treated to remove components which after the r?ing of the coffee contribute to the presence of compounds having an irrita?ng effect in the gastro-intestinal tract, without substantial loss of caffein.
The beans are washed at elevated temperature and substantially atmospheric pressure with a solvent consisting of an ester or a ketone naturally occurring in freshly roasted coffee in proportions higher than 10 ppm and having a boiling range between 50°C and 100°C. Subsequently the beans are mechanically separated from the solvent, and the solvent concentration in the green beans is reduced, using water and/or vacuum and/or steam, to a level such that, after roasting, the beans will contain a proportion of the solvent substantially within the normal range for freshly-roasted coffee.
Abstract of the Disclosure Green coffee beans are treated to remove components which after the r?ing of the coffee contribute to the presence of compounds having an irrita?ng effect in the gastro-intestinal tract, without substantial loss of caffein.
The beans are washed at elevated temperature and substantially atmospheric pressure with a solvent consisting of an ester or a ketone naturally occurring in freshly roasted coffee in proportions higher than 10 ppm and having a boiling range between 50°C and 100°C. Subsequently the beans are mechanically separated from the solvent, and the solvent concentration in the green beans is reduced, using water and/or vacuum and/or steam, to a level such that, after roasting, the beans will contain a proportion of the solvent substantially within the normal range for freshly-roasted coffee.
Description
~L~97533 It is a well-known fact that roasted coffee contains compounds which act as irritants in the gastro-intestinal tract of a not inconsiderable percentage of potential users.
Many attempts have been made to submit the green beans to a treatment for removal of the irritating components or/and their precursors, preferably without reducing the caffein content, in order to produce what is known as "mild coffee".
The irritating effect has been linked to substances which are for the most part present in the waxy layer sur-rounding the green coffee beans. Some investigators are ofthe opinion that these substances are carboxyl-5-hydroxy tryptamides (in abbreviation C5HT's). At any rate these C5HT's are used as indicators for the presence of the waxy layer, which has to be removed in order to reduce the irri-tating effect of the coffee. Fox more details see e.g. the literature mentioned in U.S. Patent specification 3,770,456, in which also the older - unsatisfactory - methods are men-tioned for the manufacture of "mild coffee".
~n entirely satisfactory process for the removal of the coffee wax or at least the irritating substances contained therein has to meet many requirements, among which are the following:
1. The processing shou,ld not leave in the green beans substances which after roasting of the coffee give rise to a. organoleptic deviations of the brew made from that roasted coffee;
b. deviations in appearance of the roasted beans;
c. health hazards.
Many attempts have been made to submit the green beans to a treatment for removal of the irritating components or/and their precursors, preferably without reducing the caffein content, in order to produce what is known as "mild coffee".
The irritating effect has been linked to substances which are for the most part present in the waxy layer sur-rounding the green coffee beans. Some investigators are ofthe opinion that these substances are carboxyl-5-hydroxy tryptamides (in abbreviation C5HT's). At any rate these C5HT's are used as indicators for the presence of the waxy layer, which has to be removed in order to reduce the irri-tating effect of the coffee. Fox more details see e.g. the literature mentioned in U.S. Patent specification 3,770,456, in which also the older - unsatisfactory - methods are men-tioned for the manufacture of "mild coffee".
~n entirely satisfactory process for the removal of the coffee wax or at least the irritating substances contained therein has to meet many requirements, among which are the following:
1. The processing shou,ld not leave in the green beans substances which after roasting of the coffee give rise to a. organoleptic deviations of the brew made from that roasted coffee;
b. deviations in appearance of the roasted beans;
c. health hazards.
2. Preferably the process should leave the caffeln content substantially unaltered.
The loss in solid content should be negligible.
~ ?~
~Q~7533 4. The processing should be economical requiring a. little time and b. simple e~uipment In the German patent application No. l,960,694 a method is described whereby the C5HT's are removed for a large part by treating preheated green beans with preheated chlorin-ated hydrocarbons for 25-40 minutes. According to German patent application No. 2,031`,830, the green beans are treated with methylene dichloride under pressure at a temperature of 50-80C.
A fundamental drawback common to both processes is that chlorinated hydrocarbons are not naturally occurring in coffee and that it is difficult to remove these - potentially hazardous - substances so thoroughly that only traces remain.
This also presupposes a strict control of the process. Even so, the regular ingestion of chlorinated hydrocarbons, or sub-stances to which they may give rise in the roasting process, even in very sMall amounts, is not recommendable, and if the aim is - as it should be - to completely avoid potential health hazards in foods and beverages wherever possible, their presence in coffee is downright unacceptable.
According to the present invention, there is pro-vided a technically and hygienically advantageous process for removing from green coffee beans components which after the roasting of the beans contribute to the presence of gastro-intestinally irritating compounds, without substantial loss of caffein, which process is characterized by washing the beans at elevated temperature and at substantially atmospheric pressure with a solvent being an ester or a ketone naturally occurring in freshly roasted coffee in amounts higher than lO ppm and having a boiling range between 50C and 100C, mechanically separating the beans from said solvent and by application of heat and/or vacuum and/or steam, restoring the concentration of said solvent in the green beans to such a level that after roasting the coffee will have a content of the solvent which lies substantially within the normal range for freshly roasted coffee.
That the process is hygienically advantageous over the processes cited above follows from the fact that it lacks the drawbacks already discussed.
The process according to the invention is moreover technologically advantageous over these in that shorter treatment times can be achieved for washing the beans and also shorter treatment times for the removal of the excess solvent.
While according to the processes of the prior art cited above the content of solvent has to be brought back to traces of chlorinated hydrocarbons, using the process according to the invention the content of solvent remaining in the green beans may be higher without running into health hazards.
An adclitional advantage of the method according to the invention is that the loss of solids in negligible (about 0.3%)~
Other processes for the manufacture of mild coffee are mentioned in Belgian Patent No. 795,949 and Netherlands Patent Application 74,07658. These involve oxidation pro-cesses in which the green beans are heated under pressure and at temperature above 100C with water vapour and air, oxygen or ozone. It is however difficult with these methods to obtain an organoleptically satisfactory product. Advanta-geously in the process according to the present invention time and temperature of the washing process are chosen so that there is substantially no loss of caffein.
~Q~753~
In order to keep the washing time as short as possi-ble, in a preferred embodiment of the invention the washing is accomplished at a temperature near or at the boiling point of the solvent and the treatment time remains below 12 minutes.
Very good results have been obtained with methyl ethyl ketone as a solvent and satisfactory results with methyl-acetate.
After having been washed, the beans are mechanically separated from the solvent e.g. by a filtering process and preferably treated with steam to remove excess solvent. Con-veniently the content of methyl ethyl ketone may be reduced to about 18 ppm and of methylacetate to about 6 ppm.
The invention lends itself very well to a continuous process in which the washing is performed by moving the beans and the solvent countercurrently.
Conveniently the volume of solvent used when the process according to the invention is performed batchwise may be from 0.4 to 1.5 times the bulk volume of the coffee, or 0.5 to 2 by weight.
The invention also encompasses green coffee beans ~ -treated according to the invention and roasted coffee manu-factured from these beans.
250 g green beans of blended coffee were extracted for 10 minutes with 500 ml of methyl ethyl ketone at 70C.
The C5HT content was reduced from about 800 ppm to 174 ppm.
The loss of caffein was negligible and the loss of solids 0.21~.
After mechanically separating the beans from the solvent the beans were heated with steam at atmospheric pressure and subsequently dried in a fluid bed dryer at 90C.
7~i33 With a steam treatment of 0.5 hour the content of methyl ethyl ketone in the beans was reduced to 18 ppm, and with a steam treatment of 1 hour to 6 ppm.
It was found that, after roasting the green coffee obtained in this way, only a few percent (less than 5%) of its original content of C5HT was decomposed (by pyrolysis), while it is possible that it is these very products of pyrolysis that have an irritating effect.
Appearance and cup quality of this roasted product were not impaired, when tested by experts, when compared with roasted coffee of the same blend without the pretreatment according to the invention.
The process parameters were the same as in Example 1, except that methylacetate was used, at a temperature of 50C. instead of methyl ethyl ketone.
In this case a steam treatment of 0.5 hour left
The loss in solid content should be negligible.
~ ?~
~Q~7533 4. The processing should be economical requiring a. little time and b. simple e~uipment In the German patent application No. l,960,694 a method is described whereby the C5HT's are removed for a large part by treating preheated green beans with preheated chlorin-ated hydrocarbons for 25-40 minutes. According to German patent application No. 2,031`,830, the green beans are treated with methylene dichloride under pressure at a temperature of 50-80C.
A fundamental drawback common to both processes is that chlorinated hydrocarbons are not naturally occurring in coffee and that it is difficult to remove these - potentially hazardous - substances so thoroughly that only traces remain.
This also presupposes a strict control of the process. Even so, the regular ingestion of chlorinated hydrocarbons, or sub-stances to which they may give rise in the roasting process, even in very sMall amounts, is not recommendable, and if the aim is - as it should be - to completely avoid potential health hazards in foods and beverages wherever possible, their presence in coffee is downright unacceptable.
According to the present invention, there is pro-vided a technically and hygienically advantageous process for removing from green coffee beans components which after the roasting of the beans contribute to the presence of gastro-intestinally irritating compounds, without substantial loss of caffein, which process is characterized by washing the beans at elevated temperature and at substantially atmospheric pressure with a solvent being an ester or a ketone naturally occurring in freshly roasted coffee in amounts higher than lO ppm and having a boiling range between 50C and 100C, mechanically separating the beans from said solvent and by application of heat and/or vacuum and/or steam, restoring the concentration of said solvent in the green beans to such a level that after roasting the coffee will have a content of the solvent which lies substantially within the normal range for freshly roasted coffee.
That the process is hygienically advantageous over the processes cited above follows from the fact that it lacks the drawbacks already discussed.
The process according to the invention is moreover technologically advantageous over these in that shorter treatment times can be achieved for washing the beans and also shorter treatment times for the removal of the excess solvent.
While according to the processes of the prior art cited above the content of solvent has to be brought back to traces of chlorinated hydrocarbons, using the process according to the invention the content of solvent remaining in the green beans may be higher without running into health hazards.
An adclitional advantage of the method according to the invention is that the loss of solids in negligible (about 0.3%)~
Other processes for the manufacture of mild coffee are mentioned in Belgian Patent No. 795,949 and Netherlands Patent Application 74,07658. These involve oxidation pro-cesses in which the green beans are heated under pressure and at temperature above 100C with water vapour and air, oxygen or ozone. It is however difficult with these methods to obtain an organoleptically satisfactory product. Advanta-geously in the process according to the present invention time and temperature of the washing process are chosen so that there is substantially no loss of caffein.
~Q~753~
In order to keep the washing time as short as possi-ble, in a preferred embodiment of the invention the washing is accomplished at a temperature near or at the boiling point of the solvent and the treatment time remains below 12 minutes.
Very good results have been obtained with methyl ethyl ketone as a solvent and satisfactory results with methyl-acetate.
After having been washed, the beans are mechanically separated from the solvent e.g. by a filtering process and preferably treated with steam to remove excess solvent. Con-veniently the content of methyl ethyl ketone may be reduced to about 18 ppm and of methylacetate to about 6 ppm.
The invention lends itself very well to a continuous process in which the washing is performed by moving the beans and the solvent countercurrently.
Conveniently the volume of solvent used when the process according to the invention is performed batchwise may be from 0.4 to 1.5 times the bulk volume of the coffee, or 0.5 to 2 by weight.
The invention also encompasses green coffee beans ~ -treated according to the invention and roasted coffee manu-factured from these beans.
250 g green beans of blended coffee were extracted for 10 minutes with 500 ml of methyl ethyl ketone at 70C.
The C5HT content was reduced from about 800 ppm to 174 ppm.
The loss of caffein was negligible and the loss of solids 0.21~.
After mechanically separating the beans from the solvent the beans were heated with steam at atmospheric pressure and subsequently dried in a fluid bed dryer at 90C.
7~i33 With a steam treatment of 0.5 hour the content of methyl ethyl ketone in the beans was reduced to 18 ppm, and with a steam treatment of 1 hour to 6 ppm.
It was found that, after roasting the green coffee obtained in this way, only a few percent (less than 5%) of its original content of C5HT was decomposed (by pyrolysis), while it is possible that it is these very products of pyrolysis that have an irritating effect.
Appearance and cup quality of this roasted product were not impaired, when tested by experts, when compared with roasted coffee of the same blend without the pretreatment according to the invention.
The process parameters were the same as in Example 1, except that methylacetate was used, at a temperature of 50C. instead of methyl ethyl ketone.
In this case a steam treatment of 0.5 hour left
3.6 ppm of the solvent in the beans and a steam treatment of 1 hour to 0.5 ppm.
The C5HT content was reduced from about 800 ppm to 259 ppm. The loss of caffein was negligible and the loss of solid was 0.18%.
. . _ 80 g green Santos beans were extracted for 10 minutes with 150 ml of methyl ethyl ketone at 75C. The C5~T
content was reduced from 1048 ppm to 186 ppm on dry solids basis. The loss of caffein was 0.01% and the loss of solids 0.4% calculated on dry solids basis.
Thereafter the beans were f-urther processed as described in Example 1.
The C5HT content was reduced from about 800 ppm to 259 ppm. The loss of caffein was negligible and the loss of solid was 0.18%.
. . _ 80 g green Santos beans were extracted for 10 minutes with 150 ml of methyl ethyl ketone at 75C. The C5~T
content was reduced from 1048 ppm to 186 ppm on dry solids basis. The loss of caffein was 0.01% and the loss of solids 0.4% calculated on dry solids basis.
Thereafter the beans were f-urther processed as described in Example 1.
Claims (8)
1. Process for removing from green coffee beans components which after roasting of the coffee contribute to the presence of gastro-intestinally irritating compounds without substantial loss of caffein characterized by washing the beans at elevated temperatures and at substantially atmos-pheric pressure with a solvent consisting of methyl ethyl ketone or methylacetate, mechanically separating the beans from said solvent and by application of heat and/or vacuum and/or steam, lowering the concentration of said solvent in the green beans to such a level that, after roasting, said beans will have a content of the solvent which lies sub-stantially within the normal range for freshly roasted coffee.
2. Process according to Claim 1, wherein the washing is accomplished at a temperature near or at the boiling point of the solvent.
3. Process according to Claim 2, wherein the green beans after having been washed are treated with steam in such a way that the content of methyl ethyl ketone is lowered to below 24 ppm.
4. Process according to Claim 3, wherein the green beans after having been washed are treated with steam in such a way that the content of methylacetate is lowered to below 16 ppm.
5. Process according to Claim 4, wherein the beans are washed with a volume of the solvent which is from 0.4 -1.5 times the bulk volume of the coffee beans.
6. Process according to any one of Claims 3, 4 and 5, wherein the washing time is less than 12 minutes.
7. Continuous process according to Claims 3, 4 and 5, wherein the beans and the solvent are moved counter-currently.
8. Green coffee beans substantially devoid of components which after the roasting of coffee contribute to the presence of gastro-intestinally irritating compounds without substantial loss of caffein, when prepared by the process defined in Claim 1 or by an obvious chemical equiva-lent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA264,008A CA1097533A (en) | 1976-10-21 | 1976-10-21 | Process for manufacture of "mild coffee" |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA264,008A CA1097533A (en) | 1976-10-21 | 1976-10-21 | Process for manufacture of "mild coffee" |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1097533A true CA1097533A (en) | 1981-03-17 |
Family
ID=4107106
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA264,008A Expired CA1097533A (en) | 1976-10-21 | 1976-10-21 | Process for manufacture of "mild coffee" |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1097533A (en) |
-
1976
- 1976-10-21 CA CA264,008A patent/CA1097533A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |