DE1960694C3 - Process for removing waxy substances and carboxylic acid-5-hydroxy) -trytamides from raw coffee beans while maintaining the original caffeine content - Google Patents

Description

The invention relates to a method for removing waxy substances and carboxylic acid-5- (hydroxy) -tryptamides from raw coffee beans while maintaining the original caffeine content.

Coffee beans are not well tolerated by some people with sensitive digestive organs. These Incompatibility is due to impurities, dietary fiber, roast residues and the like, as well as foreign bodies more mineral or organic, e.g. B. cellulose. Various studies have already been undertaken to identify these aforementioned substances remove from the coffee.

In addition to the aforementioned substances are on and under the surface of the coffee beans in a thin layer extremely adherent, waxy deposits are responsible for the poor digestibility of roasted coffee. These waxy deposits are somewhere between normal, untreated green coffee beans 0.2 and 2.0% of the bean weight. Even if these waxy deposits are only partially analytical identified, it can be said with certainty that carboxylic acid-5- (hydroxy) -tryptamide is one of the important components of these waxy deposits include. These can be proven analytically. Clinical tests have shown that the content of carboxylic acid 5- (hydroxy) -tryptamides is in direct proportion stands for the digestibility of coffee beans.

If you work carefully - for example by mechanical treatment with fine sand - it can be used a large amount of the coffee wax is removed from the surface of the green coffee. On this one Some processes for the production of wholesome coffees are based on principle, whereby the removal the carboxylic acid-5- (hydroxy) -tryptamide consistently succeeds to 25%, at most up to 48%, but what with greater loss of the coffee bean substance is connected and also brings organoleptic disadvantages.

Of the other refinement processes that are used to produce a wholesome green coffee those machining processes have achieved the greatest importance and dissemination at to which green coffee is exposed to the action of water vapor. Procedures of this type correspond more or less the "Lendrich method" (German patent 576515). The peculiarity of this Refinement process is seen in the fact that by steaming the green coffee under pressure a taste improvement and thus a better digestibility should be achieved at the same time.

The hypothesis ascribed to this process, that this leads to a reduction in chlorogenic acid of roasted coffee has not been confirmed. The chlorogenic acid content in steamed Coffee is not significantly different from that in ordinary, untreated coffees. However occurs by superficial abrasion and by washing out water-soluble substances from the raw Beans have a certain reduction in certain coffee ingredients that are found in coffee infusions Reduction of the ethyl ether-soluble substances represents by the damping process it also comes to a certain decrease in carboxylic acid 5- (hydroxy) -tryptamide, but only in the range of about 10 to 20%.

In the production of decaffeinated coffee, it is already known by choosing certain solvents the encrusted, waxy substances of the hard-to-penetrate outer layers of coffee beans to dissolve and so to get to the deeper caffeine with this solvent and this to be removed (German patent specification 598 379). This known method is not about the Production of an eaffeinated, but digestible one Green coffee, but about the de-caffeination of green coffee.

The object of the invention is to propose a method that allows extensive removal of the firmly adhering cuticular wax and thus the carboxylic acid-5- (hydroxy) -tryptamide enables to the manageability and to significantly increase the tolerance of a coffee containing caffeine without loss of the Coffee bean substance and without any influence on the organoleptic quality of the coffee.

The invention therefore consists in a process for removing waxy substances and carboxylic acid 5- (hydroxy) tryptamides from raw coffee beans while maintaining the original caffeine content, the coffee beans being treated with a solvent from the group of chlorinated hydrocarbons close to the boiling point of the solvent and this is then removed, which is characterized in that preheated to a temperature of 40 to 48 ° C and cleaned dry coffee beans are washed with the preheated solvent for a time of 25 to 40 minutes while maintaining the temperature of the solvent.
It has surprisingly been found that complete retention of the caffeine content with simultaneous removal of the waxy substances to a content which is in any case below the values obtained in the "Lendrich process" can be achieved by adjusting the temperature of the green coffee and the solvent on the one hand and the treatment time on the other hand is possible. The preheating of the green coffee and the solvent is of crucial importance for maintaining the

Caffeine on the one hand and a long way off the undesirable roasting irritants (analytically detectable by determining the remaining hydroxytryptamides) on the other hand. The procedure is therefore not comparable with the long-term treatment of green coffee for decaffeination. Even premature termination of the decaffeination treatment would not be part of the present invention Lead result, in particular because of the preheating of the green coffee that is not customary there.

The upper temperature limit when preheating the green coffee is determined by the fact that at increased

10

Temperatures, from around 55 ° C, the green coffee gets an undesirable and unacceptable discoloration and adversely changes in taste. The optimal temperature of the preheated coffee beans and the solvent gives the finished product the best organoleptic properties.

To the surprising effect, which in the process according to the invention by preheating both the green coffee beans and the Solvent results, to make believable, experiments were carried out, the results of which in the are summarized in the following tables.

Table 1 treatment with preheating 41 C2H4CI2) with and without preheating of 943 mung Temperature ("C) 45 Go to CHT *) after the treatment 919 (in ppm) without preheating Solvent bean 46 without preheating with preheating 862 512 Temperature (° C) 21 48 vnung 902 423 Bean 23 52 Solvent (in ppm) 925 401 Treatment of green coffee beans with ethylene chloride (1,2-dichloroethane =
Beans and solvents 18th 20th 48 74 931 321 Treatment 20th 22nd 45 83 880 291 QdUCr in
Minutes 21 23 82 400 19th 20th 84 314 20th 21 82 20th 22nd 84 20th 20th 80 30th 30th 30th 20th 30th

Remarks:

·) CHT = carboxylic acid-5-hydroxy-tryptamide.

CHT value in the beans before treatment = 1043 ppm.

From the above values, it can be seen that the CHT value is lower when both the beans and the solvent must be preheated.

There was no loss of caffeine during the treatment. The caffeine values in the treated and untreated samples agreed within the analytical error limits.

Table 2

Influence of the extent of preheating on the extraction result as well as properties and appearance of the Beans

Preheating of beans

CHT loss

of the solvent)

Color of the toasted image Beans

Coffee cup

I a) 70 ° C 80 ⁰ C after 20 minutes of treatment
duration
79.2O / o
after 30 minutes of treatment
duration
82.4% Red
Red very bad
very bad bad b) 42 ° C 75 ⁰ C after 30 minutes of treatment
duration
78.2% Well Well Well c) 40 ° C 70 ° C after 30 minutes of treatment
duration
78.4% very good very good very good d) no prior
warming
18 ° C temperature 24 ° C after 30 minutes of treatment
duration
46.2% very good very good Well

*) C2H4Cl2 was used as the solvent.

Experiments a) to d) are laboratory experiments with small amounts customary in laboratories. A loss of caffeine occurred with the Treatment does not include (differences within the analytical error limits).

In addition to the laboratory tests described in Table 2, so-called production tests were also carried out carried out in which the test conditions were the same as given above, but with Quantities of more than 1000 kg have been worked.

The solvent was kept moving in opposite directions with the coffee beans during the tests. The results of these tests, which comprised a treatment time of 30 minutes, can be found in following table 3.

Table 3

a) No preheating temperature

of beans 19 "C

of the solvent 23-C

After 30 minutes Caffeine loss koiner CHT loss 48.2%

The beans are color and roasted, as are the coffee infusion

b) With preheating temperature

of beans to 40 ° C

of the solvent to 68-72 ° C

After 30 minutes No caffeine loss CHT loss 84.6%

The color and roast of the beans are very good, as is the coffee infusion

The results of the tests described in Tables 1 to 3 can be summarized to the effect that a greater removal of the CHT can be achieved than without preheating.

One more fabrication trial was made to show all of the results be cheaper if both the beans and the solvent are preheated. These were Lots of green coffee, more than 1000 kg, with ethylene chloride treated as a solvent for 30 minutes

II

Loss of caffeine CHT loss Appearance of the beans Coffee infusion

extract volume

none 48.1 Well Well

243 281

none 843 Well

mild, rounded 24.4 314

I: no preheating; Temperature of beans 20 ° C,

Solvent temperature 22 ° C II: with preheating;

Temperature of beans 41 ° C, Solvent temperature 70 to 72 ° C.

Finally, comparative tests were carried out in which in some approaches the beans were not preheated, the solvent, however, up to almost was heated to boiling point. In this way it should be shown that the inventive Procedure differs fundamentally in its effects from the known procedure in which raw coffee beans with the extractant poured over them, on one of the boiling point of the concerned The temperature close to the solvent is heated and continuously extracted.

Table 4

try

Processing time Minutes

Temperature, "C, des

Coffees

Solvent

Caffeine content

C-5-H-T

in ppm

Remarks

Ll 25th 18th 20th L2 25th 18th 50 L3 25th 18th 80 L4 40 18th 50 L5 40 18th 80 L6 50 18th 80 L7 80 18th 80 L8 25th 48 20th L9 25th 48 50 LlO 25th 48 80 LIl 40 48 80 L 12 50 48 80 L 13 80 48 80 L 14 120 18th 20th L15 120 18th 80 L16 120 48 80 Fl 40 18th 20th F2 40 18th 80 F3 40 48 20th F4 40 48 80

1.16 844 1.16 761 1.16 595 1.15 435 1.16 428 1.14 433 1.12 398 1.16 395 1.15 297 1.15 258 1.16 219 1.14 222 1.11 198 1.14 423 1.13 338 1.09 189 not determined 442 not determined 389 not determined 226 not determined 194

The values given are the average in each case 2 to 3 individual attempts

In the above table 4, which contains the mentioned comparative tests, Ll, L 2, L3 etc. successive laboratory tests, which were carried out with a green coffee blend (20 Col / 12Sal) became. The caffeine content of the raw coffee was 1.16%, the CHT content 1078 ppm. As a solvent ethylene chloride was used. 1400 g of green coffee were treated with 1800 ml of solvent. To After the treatment, the solvent was drained off and the coffee steamed and dried. F 1, F 2 etc. denote manufacturing tests carried out under appropriate conditions with quantities of more than 1000 kg.

Experiments L 9 to L 12 and F 4 clearly show the advantageous effect of the treatment according to the invention.

Evidence of the withdrawal of incompatible cuticular wax can be provided by analytical determination the amount of carboxylic acid-5- (hydroxy) -tryptamide removed. By comparison with those for the Individual provenances known original proportions can thus be determined exactly which result the The amount of carboxylic acid 5- (hydroxy) -tryptamide has resulted in the treatment of the green coffee according to the invention is in direct proportion to the amount of cuticular wax. The possibility of a subsequent accurate evidence of the withdrawal of these incompatible substances is one of the advantages of Invention. The process according to the invention enables 70 to 84% removal of the carboxylic acid 5- (hydroxy) tryptamides achievable, that is, a result that is considerably improved compared to previous methods.

In order to further improve the digestibility and tolerance of the green coffee, the washed Green coffee can then be subjected to further treatments. First, the invention provides a Steaming of the coffee that has already been treated, by means of which substances soluble in ethyl ether are removed. the Any solvent residues present from the washing process are mixed with suitable, known Measures removed, with the remaining residues of chlorinated hydrocarbons below 10 ppm lie.

Then, by rapid drying with simultaneous rubbing and grinding of the surface of the Coffee beans also removes the skins loosened during the steaming process. The drying takes place until on the original moisture of the coffee beans. Then these are placed under a stream of cold air Cooled down as quickly as possible Through this rapid cooling of the coffee beans, the last remnants of the Coffee wax (identified as carboxylic acid-5- (hydroxy) -tryptamide) to the surface of the beans and are largely removed there by additional grinding and polishing

The processing losses to be recorded when using the method according to the invention Coffee is limited to those substances that affect its digestibility. The bean substance remains.

In practice, the method according to the invention can be carried out as follows:

For the production of low-irritant and digestible coffees according to the invention appropriately selected provenances by nature

H) from already a lower content of carboxylic acid 5- (hydroxy) -tryptamides exhibit. The content can be determined analytically.

The coffee beans are first treated mechanically in a commercially available coffee cleaning machine, in which, in addition to removing impurities (stones, sand, etc.), special emphasis is placed on rubbing off superficial foreign bodies, e.g. B. silver skin u. Ä. Is placed.
The beans are then preheated in a heatable container. Depending on the type of coffee, the most appropriate temperature is between 40 and 48 ^° C. At the same time, the solvent is preheated in other containers. The best solvent is methylene chloride (dichloromethane, CH ₂ Cl ₂ , boiling point

point 40 ° C), 1,2-dichloroethane (ethylene chloride, C ₂ H ₄ Cl ₂ , boiling point 84 ⁰ C), trichlorethylene (CICH = CCl ₂ , boiling point 87 ° C) or mixtures of the aforementioned solvents. The solvent is brought to a temperature that approaches the respective boiling point as closely as possible. The preheated coffee beans are fed into a heatable container at the same time as the preheated solvent. The temperature must be kept at the boiling point while the coffee beans and the solvent move in opposite directions. The time of this process, during which there is still no loss of caffeine, is 25 to 40 minutes, depending on the intensity of the solvent and the type of coffee used. The right combination of temperature and time is essential for the optimal degree of dissolution of the cuticular wax without affecting the caffeine content.

After this treatment, the solvent is removed from the coffee in a known manner and Residues are driven off and then the coffee with constant movement and constant pressure analogous to that "Lendrich process" subdued. After this steaming process, the beans are put into a drying unit, which must contain a device with which one

such a rubbing and grinding of the surface of the beans is achieved with simultaneous deduction of the at the same time Damping process of loosened cuticle. Subsequent rapid cooling drives further remaining wax particles on the surface of the bean, which is rubbed off by additional mechanical treatment.

Claims (2)

Patent claims: 1. Process for the removal of waxy substances and carboxylic acid JvihydroxyJ-tryptamides from raw coffee beans while maintaining the original caffeine content, whereby the coffee beans with a solvent from the group of chlorinated hydrocarbons close to the boiling point of the Solvent are treated and this is then removed, characterized in that that to a temperature of 40 to 48 ° C preheated and cleaned dry coffee beans with the preheated solvent for a period of 25 to 40 minutes while maintaining the temperature of the solvent. 2. The method according to claim 1, characterized in that after washing and after a known steaming of the green coffee with simultaneous rubbing and grinding of the surface the coffee beans are dried to the original moisture level by rapid drying and then cooled in a cold air stream within a short time and the bean surface again machined by grinding and polishing.