CA1331846C - Coffee and process for the production thereof - Google Patents

Abstract

ABSTRACT
Roasted coffee with an increased chlorogenic acid content of more than 2.8% by weight or instant coffee powder with an increased chlorogenic acid content of more than 8.5% by weight have a better compatibility. The increased chlorogenic acid content is achieved either by adding chlorogenic acid or by extracting raw coffee and addition the optionally concentrated extract of the roasted coffee.

Description

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The invention relates to roasted or instant coffee with an increased chlorogenic acid content, as well as to processes for the production thereof.

Chlorogenic acid is here not only understood to mean the 3-ca$feoylquinic acid mostly contained in coffee and frequently referred to in the literature as ~the chlorogenic acid~, but also 4- and 5-caffeoylquinic acid, as well as iYomeric mixtures.

~hen roasting ra~ coffee a considerable weight loss occurs and generally represents approximately 12 to 17~ by weight. The loss is not only due to the residual moisture content still present in the raw coffee after dryin~, and vhich is lost during roasting and in addition various constituents of the rav coffee are evaporated or chemically decomposed during the roasting process and are consequently lost.
Chlorogenic acid is among the constituents of raw coffee, ~hose content is significantly reduced by roasting. This decomposition of chlorogenic acid has hitherto been accepted, because it vas looked upon as an undesired component (cf. German patent 685 367, p.l, lines 44/45). - -Various processes for the production of low-caffeine or caffeine-free coffee by re-oving caffeine from the raw coffee are known. In these processes, the rav coffee is estracted with water or some other solvent and then using organic solvents or solid adsorbents the caffeine is ' removed from the e~tract (German patent 685 367/European patent 8398).
The caffeine-free estract can optionally be added to rav coffee again, 80 that the green coffee beans vhich undergo the roasting process fully contain all constituents other than caffeine (German patent 685 367, p.l, lines 29 to 31. It has already been described how the caffeine can be removed from the raw coffee in such a WAy that it is brought into contact with an estract which is saturated with all estractable constituents, other than the caffeine. The caffeine of the rav coffee passes selectively into said estract and is subsequently withdrawn again (DE-OS 31 19 277/EP-OS 78088). This process also leads to a low-caffeine or decaffeinated raw coffee, during the roasting of which other constituents and in particular a considerable part of the q~
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chlorogenic acid are lost. In the earlier processes the chlorogenic acid is even removed during e~traction as an allegedly undesired component (German patent 6B5 367, p.l, lines 43 to 49).

In has now been found that roasted or instant coffee with a higher content of the conseituents of the raw coffee, particularly chlorogenic acid csn be more easily digestet and that in this way a higher weight yield of roasted coffee can be obtained from the raw coffee without any loss of taste or flavour. It has particularly surprisingly been found that chlorogenic acid is able to protect the gastric mucosa against irritations ant therefore improves the digestibility of foods, beverages and modicuments, cf. the parallel German patent application P
36 03 576.9-41.

The improved digestibility is proved by a much reduced acid secretion.
This reduction is clearly obtained in that the proportion of roasting substances present in any roasted coffee and whose physiological effect causes incompatibilities (heartburn, etc), is compensated by an increased chlorogenic acid content.

Therefore the digestibility of a roasted coffee is dependent on the chlorogenic acid/roasting substance ratio in the coffee infusion. From this standpoint it vould be desirable to prevent a marked reduction in the chlorogenic acid content through the roasting of the coffee. -~
Normally the natural chlorogenic acid content of coffee is reduced by appro~imately 40 to 802 during roasting, so that in roasted coffee there is only about 2~ by weight and at the most appro~imately 2.4 to 2.6~ by weight of chlorogenic acid (determined by means of ~PLC). -Earlier works (e.g. G. Lehmann et al, Deutsche Lebensmittel-Rundschau, 63, pp. 144-151 and 273-275, 1967; G. Lehmann, Ernahrungs-Umschau 1971, pp. 43-47) admittedly report on much higher chlorogenic acid content in roasted coffee and instant coffee powders. However, the determination ~-method used also covered other phenolic compounds and therefore yielded much higher value. All the chlorogenic acid values given in the - -~
present description and claims ~ere obtained by the HPLC method (high pressure li~uid chromatography) and are therefore appro~imately 50 lower than those obtained by the previously used DIN method or other L

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earlier determinstion methods (cf. G. Lehmann and B. Binkle, Deutsche Lebensmittel-Rundschau 79, pp. 266-269, 1983, ~. Schunemann and H.G.
Maier, Duetsche Lebensmittel-Rundschau B2, pp. 73-76, 1986).

The present invention therefore relates to roasted coffee with an increased chlorogenic acid content of more than 2.8Z by weight, preferably at least 3Z by weight and e.g. 3.25Z by weight or more, or instant coffee powders with an increased chlorogenic acid content of more than 8.5Z by weight.

As has already been stated, the chlorogenic acid content of conventional roasted coffee is only appro~imately 22 by weight and in rare cases reaches approximately 2.4 to 2.6Z by weight. Only as a result of e~treme mild roasting, which no longer provides a coffee with a satisfactory flavour, could higher chlorogenic acid content be obtained.

The chlorogenic acid content range of the inventive roasted coffee, in which a positive physiological effect in the sense of better .
digestibility can be proved, generally starts at appro~imately 2.8Z by weight, hilst taking account of the aforementioned relationship between the chlorogenic acid content and the roasting substance potential. The latter is dependent on the degree of roast~ng and the e~tractability of the roasted coffee. This means that percentagewise the chlorogenic acid content should be increased by at least the same amount by which in each case the roasting substance content increases (measured as a colour value of the ground coffee). The colour value of commercially available, normally roasted coffee varieties is appro~imately 90Z. In the case of the roasting substance content corresponding to the colour value in the infusion, according to the invention generally a chlorogenic acid content in the roasted coffee of appro~- 2.8~ by weight is adequate. On lowering the colour value (corresponding to a rising roasting substance content), according to the invention the chlorogenic acid content must be raised by at least the same amount. If e.g. through stronger roasting the colour value drops to 80, i.e. by appro~imately 12Z, the chlorogenic acid content is preferably increased by at least 12Z, i.e. to appro~imately 3.14Z by X

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weight, in order to effectively compensate the physiological effect of the roasting substances.

The colour value determined by reflection measurement on ground roasted coffee is recognised to be a measure of the degree of roasting of coffee.

It has been found that an increased chlorogenic acid content can be achieved in different ways and the roasted coffee can contain the chlorogenic acid partly in the form of salts, particularly alkali metal salts and in particular potassium salts. In the human stomach, such salts have the same effect as free chlorogenic acid, because in the strong acid gastric medium they are largely converted into the free acid.

For protucing the roasted coffee, it is possible to proceed in such a vay according to the invention that by treating the raw coffee with a -solvent an estract is produced, the e~tracted coffee and/or a non~
e~tracted coffee charge is roasted, the optionally concentrated e~tract -~$s vholly or partly added to the roasted coffee before or after --~
grinding snd the coffee is then dried. The constituents of the rav coffee estract consequently bypass the roasting and are subject to no decomposition.

Preferably vater is used as a solvent. Prior to the impregnation of the roasted coffee vith the raw coffee e~tract, the latter is preferably concentrated, so that it has a solids content of more than ;
15 and in particular more and 20Z by veight. The e~tract is sprayed or ~- -dusted onto the roasted coffee, i.e. the roasted beans or optionally also the already ground coffee. Drying then takes place to remove the moisture at appro~imately 60 to 120C and preferably at approsimately ~ -80 to ~00C, in order to remove the moisture emanating from the estract.

Approsimately 25 to 28~ by weight of the dry substance of green coffee beans are estractable, but according to the invention generally only approsimately 5 to 82 by veight are estracted. There is no need to . y 1333 8~ -s subsequently add the entire e~tract to the roasted coffee. Instead, only part of the rsw coffee estract and/or specific constituents csn be selected for this. For esample certain selected constituents can be separated from the ra~ coffee estract and they are then added to the coffee again after roasting, whereas 0 to lOOZ of the estract left behint $s again added to the raw coffee prior to roasting. In other words certain constituents are selected rom the estract and added to the roasted coffee, vhereas other constituents are either wholly or partly supplied again to the raw coffee, then undergo the roasting process or are completely separated and discarded.

For the separation of chlorogenic acid from raw coffee estracts, it is possible to use gel permeation chromatography, where e.g. modified polysaccharides are used, vhich in conjunction with vater give a heteroporous, swollen netvork vith variable pore size distribution.
The fractionation of the dissolved substances normally takes place according to the olecular size. In the case of the chlorogenic acid, it has been found that another echanis- ust come into effect, because the acid is held uch longer than vould be espected on the basis on its molecular size. It therefore only appears in the final eluate fractions. the chlorogenic acid-free and the chlorogenic acid-containing eluates are separatel~ collected and concentrated. The for er are optionally added to the rav coffee and the latter ~o the roasted coffee produced therefro~. The chlorogenic acid contents of the roasted coffee are conseguently onl~ dependent on the partial --degree of the e~traction of the rav coffee and can be adjusted at random vithin this range. This simultaneously leads to a quantitative gain, as stated hereinbefore, because the material subsequentl~ added to the roasted coffee is subject to no thermal deco-position.

~nother possibility for raising the chlorogenic acid content in the roasted coffee is to estract approsimately 5 to 10~ by veight of the soluble constituents from the rav coffee, the resulting solution i8 concentrated to a solids content of e.g. 20~ and vithout further treatment is returned to the partly estracted ra~ coffee redried to an average vater content. The thus obtained material must again be dried to a moisture content permitting subsequent roasting. This -6- 13~38~
subsequently gives a rossted coffee which, compared with untreated coffee, has an up to 0.5Z by weight higher chlorogenic acid content, vhich is possibly a consequence of the asymmetric e~tract distribution over the bean cross-section occurring during raw coffee impregnation.

Another possibility is to 80 control the process during the eYtraction, that only those constituents are removed from the raw coffee vhich are to be subsequently added to the roasted coffee again. This can e.g.
take place in such a way that for extracting the rav coffee use is made of recycled e~tract, vhich i8 only not saturated vith respect to those constituents which are subsequently added to the roasted coffee. Only these constituents pass from the bean into the solution. They are separated from the solution using suitable separating processes, removed from the cycle and subsequently added again to the roasted -~
coffee.

As e~traction of the raw coffee within the framework of the inventive process takes place by per ge known processes, such as are e.g.
described in DE-OS 31 19 277.

As e~plained hereinbefore, a particular aspect of the invention is that vith the aid thereof it is possible to obtain a roasted coffee with an increased chlorogenic acid content, in that to the roasted coffee is added a chlorogenic acid-containing e~tract. However, according to another embodiment of the invention it is also possible to mi~ roasted coffee with isolated chlorogenic acid obtained from green co$fee beans or other plants (cf. in connection vith the isolation process European Patent 258,287).

According to another embodiment chlorogcnic acid can also be added to the rav coffee, but it must be borne in mind that as a result of the thermal decomposition the additive must be dosed in such a way that the roasted product has a sufficiently high chlorogenic acid content in the sense of the invention.

According to another embodiment roasted coffee is roasted in praded manner with different degrees of roasting, so that the individual _ . , - .- -, - - . . " ~ . ; . , . : :

1333 ~fi roasts give different chlorogenic acid contents. $his gives mi~tures vhich do not differ from the sensory standpoint from conventional coffee and vhose total chlorogenic acid content is uch higher than that obtained from a unitary roast. Thus, surprisingly, this procedure in the case of a relatively high colour value (lov degree of roasting) gives a protuct which from the sensory standpoint corresponds to a coffee vith a standard degree of roasting. This also applies with respect to roasts from different origins and/or types and the selection thereof can take place under the standpoint of a high chlorogen~c ac~d content in the starting material.

The process of mi~ing differently roasted components can be looked upon as a mi~ing optimization directed at increasing the chlorogenic acid content. The thus attainable chlorogenic acid increase leads to values vhich, for obtaining the inventive chlorogenic acid content, only require supplementing by relativel~ small chlorogenic acid quantities fro- esternal sources. Hovever, it can also be obtained by suitable combinations of mi~tures optimization vith one or more of the afore-entioned process variants.

The inventive procedures can also be u~ed fro producing decaffeinated or partly decaffeinated roasted coffee, in that a rav coffee is used as a basis and then the caffeine is partly or totall~ removed therefro-.

Pulverulent soluble or instant coffee can also be obtained according to the invention. Co- ercially available instant coffee povders have chlorogenic acid contents of approsi ately 3.5 to 5.02 by veight, vhich in the case of conventional tosing leads to a chlorogenic acid content of approsi atel~ 51 to 72 mg/100 ml of coffee. Using the standard filter preparation methods, normal roasted coffee leads to a coffee beverage vith approsimately 130 mg of chlorogenic acid/ 100 ml of coffee, i.e. the chlorogenic acid content of instant coffee povders is particularly lov. ~hen using inventive roasted coffee, the coffee beverage contains chlorogenic acid contents above 160 g/100 of coffee.
Thus, according to the invention, at a suitable point in the process for producing instant coffee or the finished instant coffee povder, sufficient chlorogenic acid is added to ensure that a coffee vith a .: ~ . .: ;, ' -8- 133~ 8~

sought h$gher chlorogenic acid content is obtained. It i9 normally necessary for this purpose to add approximately 5 to 7 and in particular appro~imately 6~ by ~eight of chlorogenic acid to the instant coffee powder, 80 that its content is at least appro~imately 8.S2 by ~eight.

The following e~amples ~ithout being of a limitative nature serve to further illustrate the Invention. A11 percentages are b~ ~eight. The chlorogenic acid contents given were obtained by high pressure liquid chro atograph~ (HPLC) ~ith equipment (pump, spectral photometer, ~- ;
separation column) supplied by hessrs. ~aters and an intertrator ~upplied b~ ~essrs. Shimadzu in the follo~ing ~ay:
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Colu n: Cartridge 8 C 1810 Injection volume: 20 pl Detection: at 280 nm Plo rate: 1 to 4 ml./min hobile solvent: 20 1 of tetrahydrofuran + 1 ml of glacial acetic acid ad 1000 1 of distilled vater.

The test solution ~as prepared by e~traction of the ground starting aterial in the ultrasonic bath ~ith ~ater and filtration through a 45 fulter. The calibration solution vas a solution of S g of 3~
caffeoJlquinic acit in 100 1 of vater. The sum of the peak areas of 3-, 4- and 5-caffeo~liquinic acids vas related to the pea~ area of the co parison substance for calculating the contents.

The colour value vas deter ined vith a Tricolor LP~ 3 colori eter ; supplied by Lange-IndustriemeBgerate. For measurement purposes, ground coffee vith a standardized degree of grinding and located in a cell ~as irradiated under an angle of 45 by a light source and the diffuse reflected light ~as si ultaneousl~ detected by three photoreceivers.
The value L* (DIN 6174, CIS-LAB 1976) easured on the light-dark a~is vas used as a easure for the colour intensity of the coffee. The L*
values are converted by linear regression into the colour value, ~hich is given in scale divisions (s.d.). The following three pairs of ~ 3 .` ~

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g values give degrees of regression L* 19 69/75 s d , L* 22 30/90 s d and L* 25 77/110 s d The colour of the normally roastet coffee is 90 s d in the describet measuring process In the case of lighter roasted coffees correspondingly higher nu erical values are easuret -~ ;

Examnle 1 7 kg of raw coffee were extracted with 6 1 litre of water for ninety minutes at 80C and acco-panied by constant movement After pouring off the extract solution adhering liquid ~as removed from the beans by spraying vith water, redried to a vater content of approximately 12 5Z
and roasted in hot air at 240C The spra~ing water and extract solution vere co-bined, carefull~ evaporated to a dry substance content of approsi ately 20Z and this concentrate ~as then sprayed in a rotating flas~ onto the roasted coffee She beans absorbed the solution and ~ere then redried in the hot airflow at 90OC to a residual ~ater content of approximatel~ 3Z A non-extracted comparison sa ple of the starting aterial vas roasted directly in the anner described hereinbefore Both coffees vere then brought to the same degree of roasting for sensory co parabil~t~ purposes and the colour value easure-ent ~as used as a measure for the degree of roasting She folloving Sable l gives the analytical data obtained on a comparative basis ' %

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Table 1 Chlorogenic acid Estract Colour content content value ~ t.s. * 2 d.s. *

Inventively treated roasted coffee 3.19 27.1 92 Untreated roasted coffee 2.08 26.8 90 * d.s. - in dried substance -~

Compared ~ith the untreated product, the inventively treated product ~-had an approsimately 50~ higher chlorogenic acid content and, in spite of the higher acid content, the infusion had a surprisingly mild taste and from the sensory standpoint ~as comparable ~ith the untreated -~
sample.

Esan~le 2 7 kg of rav coffee were estracted vith vater as described in esample 1.
The resulting estract solution ~as treated vith a cation eschanger in the H~ for and consequently brought to a p~-value of 2.3. ~fter concentration the solution to an estract content of approsi-ately 20~, it undervent gel permeation chromatography for separating chlorogenic acit. In this case the separating medium ~as a relatively lo~ cross-lin~ed destran marketed under the trademark SEPHADEX G 25~ (Pharmacia A.B.). For this purpose the sample solution ~as firstly fed onto the gel bed, vhilst maintaining a sample to gel volume ratio of 1:5.
Elution took plice vith desalted, degassed water having a delivery rate of l litre of water/litre of gel bed s h for a gel bed volume of 15 litres.

As a result of the unespected affinity evolved by the chlorogenic acid vith respect to the destran matris, as described hereinbefore, it is more 910vly eluted than would have been espected on the basis of its X

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molecular size and leaves the column virtually after all the other extract constituents. The latter vere therefore collected as the first fraction, whereas the second frsction mainly contained the chlorogenic acid isomers. The purity of the isometric misture in the second fraction was appro~imately 80~. Both fractions were carefully concentrated to a concentration of in each case appro~imately 20Z.

The partly estracted raw coffee was redried to a water content of approsimately 12 to 15~ and impregnated with the almost chlorogenic acid-free concentrate of the first fraction by spraying at 50C in the rotating flas~. Over a period of approsimately one hour, the beans absorb the estract solution. Then again approsimately 0.5 litre of water was sprayed on in approsimately 30 minutes, which led to a further absorption in the interior of the bean of also the esternally adhering estract residues. After hot air drying at approsimately 90C
to a residual oisture content of 14~, the beans were roasted in a hot airflow at 240C to a colour value of 90 scale divisions. The concentrated chlorogenic acid solution was then sprayed onto the still war roasted beans in the rotating flask and the beans compared with were then redried in the hot airflow at 90C. The results compared with the untreated, directly roasted coffee are given in Table 2.

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Table 2 Chlorogenic acid Extract Colour content content value ;~
Z d.s. * Z d.s. *

Inventively treated roasted coffee 3.30 27.8 93 ~-~

Untreated roasted coffee 2.08 26.8 91 E~amole 3 From 1.1 Kg of raw coffee with a chlorogenic acid content of 5.5Z in the dr~ substance, b~ extracting three times vith in each case 4.1 litres of water at 80C, an estract solution was prepared, which was carefully concentrated from extracting chlorogenic acid, adjusted with hydrochloric acid to pH - 2, filtered and subject as a roughly 20Z
solution to gel permeation chromatography, as described in e~ample 2.
the chloride ions appear in the first eluate, which was in this ca~e discarded, acidification could take place with hydrochloric acid. The chlorogenic acit fraction was separately collected and concentrated to an approsimately 20Z dry substance content. 280 ml of this solution, whose chlorogenic acid content was approsimately 18Z, was ~prayed onto 4 }g of an otherwise untreated roasted coffee and the material was redried to an approsimately 3Z water content in the hot airflow at 80qC. Ba~ed on the given roasted coffee quantity, the chlorogenic acid addition amounted to approsimately 1.3Z. The analytical results compared with the untreated roasted coffee are given in Table 3.
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Table 3 Chlorogenic acit E~tract Colour content content value ~ d.s. * ~ d.s. *
-Inventively treated roasted coffee 3.28 28.4 91 Untreated roasted coffee 2.10 27.1 92 Esa-Dle 4 Roasts graded by the degree of roasting and prepared ~ith correspondingly differing chlorogenic acid contents were produced from raw coffees from Colo-bia, Tanzania and Kenya and isture A in Table 4 vas formed therefro-. histure H vas obt-ined in a similar manner, but consisted solely of Colombia coffee roasts.

In each case 4 kg of mistures A and H were then, as described in esample 3, impregnated vith a 20~ chlorogenic acid solution and redried. Table 4 gives the in each case added quantities of chlorogenic acid and the obtained, i.e. analytically found percentage contents.

The chlorogenic acid addition, based on the give roasted coffee misture ~as 0.51 for misture A and approsimately 0.4Z for mi~ture H.
The percentages under ~rise found~ relate to the chlorogenic acid content of the Colo-bia coffee used for co-parison purposes.

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Phvsiolo~ical tests In a test series the influence of different coffee samples on the humangastric acid secretion was investigated. Each test subject received approYimately 250 ml of the individual coffee samples in random double-blind crossover form. The test subjects were healthy males and females ages between 19 and 35. After fasting for twelve hours, the test subjects were fitted in the morning vith a naso-gastral probe by means of vhich the gastric juice was initially quantitatively removed at time to. Quantitative removal then took place at 15 minute intervals over the following si~ty minutes to60 for determining the basal acid secretion of the nev formed gastric juice. On five different test days, vhich were at least tvo days apart, the test subjects received in each case 250 ml of coffee types 1 to 5 or I to IV. the return of the gastric juice removed at the time 0 took place before the test subjects received the different coffee types vithin a ten minute period. The probe vas used for removing in each case 5 ml of gastric 3uice 10 and 30 minutes after the start of coffee drinking. Betveen the 30th and 150th minutes, there was once against a quantitative removal of the gastric juice at 15 minute intervals. The titratable acid vas determined vith O.ln NaOH in these samples and in Tables 6 and 7 the values found are given in ml of NaOH. The volume of the removed gastric juice is given in ml in Tables 6 and ~.

The period t~lSo or t~210 vas used for the comparative evaluation of the results because, as is knovn, other effects are superimposed in the ~;
first 60 minutes after ingestion. The values found vere obtained by intraindividual evaluation, the dispersion according to the folloving equation vas calculated for the mean values:

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SEh ~ N(N-~) s - mean value N ~ number of mean values Coffee samples 1 to 5 had an identical degree of roasting and only differed through risin8 chlorogenic acit quantities (Table 5), samples %

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3 to 5 corresponding to the invention As i8 shown by the results given in Table 6, coffee 1 led to the highest acid stimulation, but with rising chlorogenic acid content there was a signlficant decrease in ga6tric acid secretion Volume secretion also decreases in the order of coffee types 1 to 5 there is a clear influence of chlorogenic acid on the reduction of the human gastric acid secretion stimulated b~ coffee roasting substances Coffee types I to IV had different degrees of roasting (colour values),estract and chlorogenic acid content (Table 5) The e~tract of the individual sa ples ~as determined, in that in each case 100 ml of the coffee infusion (preparet as for the at inistration to the test subjects) vas evaporated to dryness The dry resitue obtainet is given as an estract in glloo ml of coffee The results of Table 7 show that coffee sample IV gives the lowest acid stimulation Compared ~ith coffee sa ple IV, ~a ples III, II and I lead to a much hi p er gastric acit secretion, the non-inventive sa ple III being the least favourable and this also applies as regarts to the volume secretion The results ake it clear that there is a connection bet~een the tegree of roasting ant the estract on the one hant ant the chlorogenic acit content on the other ant that a hi p er chlorogenic acit content ust correspont to a hi p roasting substance content in the infusion, in order to achieve a ver~ lov gastric acit secretion ant therefore an improved co patibility Coffee sa ples A to D (Table 5) differ either vith regards to the degree of roasting or, vith the sa e degree of roasting, as regards the chlorogenic acid content Co-parison betveen samples A ant D shovs that a hi per roasting substance content (lo~er colour value corresponting to a hi p er tegree of roasting ant hi per e~tract) for the sa e chlorogenic acit content leats to the increaset acit secretion Hovever, sa-ples B and C prove that in the case of coffees vith an identical roasting substance content, the sa ple vith the hi8her chlorogenic acid content leads to 8 much lover gastric acid secretion :- .... ~ - :;

-17- 1~3~
Table 5 Coffee No. Chlorogenic acid content E~tract Content Degree of mg/100 ml of coffee (g/100 ml of coffee) roasting (colour ~alue) 110.O
2 134.3 3 156.8 4 17B.l 188.1 I 193 1.51 84 II 149 1.41 110 III 105 1.32 85 IV 194 1.63 87 A 124 1.36 90 B 98 . 1.37 75 C 124 1.38 75 ~ D 124 1.49 60 _ :. ;:.:, : :-:-;..... . . : : . ~,:
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Claims (18)

1. Roasted coffee with a chlorogenic acid content increased to more than 2.8% by weight or an instant coffee powder with a chlorogenic acid content increased to more than 8.5% by weight.

2. Coffee according to claim 1, characterized in that the percentage chlorogenic acid content is increased by at least the same amount by which the roasted substance content increases in the infusion (measured as a colour value of the ground coffee), based on a chlorogenic acid content of approximately 2.8% by weight in the case of a colour value of approximately 90.

3. Coffee according to claim 1, characterized in that it contains the chlorogenic acid at least partly in the form of salts.

4. Roasted coffee with a chlorogenic acid content increased to more than 2.8% by weight, said chlorogenic acid increased by chlorogenic acid removed from the raw coffee and added to the roasted coffee.

5. A process for producing coffee with an increased chlorogenic acid content according to claim 1 comprising:
1) treating raw coffee with a solvent to prepare an extract;
2) roasting a charge of coffee;
3) adding at least a portion of said extract to said roasted charge of coffee to form a mixture;
4) grinding said charge of coffee, said grinding step occurring before or after said adding step; and 5) drying said mixture, said drying step being carried out after said grinding and adding steps.

6. Process according to claim 5, characterized in that water is used as the solvent.

7. Process according to claim 5, characterized in that the raw coffee extract is concentrated to a solids content of more than 15% by weight.

8. Process according to claim 5, characterized in that drying takes place at 60 to 120 °C.

9. Process according to any one of claims 5 to 8, characterized in that from the raw coffee extract are separated the constituents which are to be added again to the roasted coffee, whilst 0 to 100% of the extract left behind is added to the raw coffee again prior to roasting.

10. Process according to any one of claims 5 to 8, characterized in that for extracting the raw coffee use is made of a recycled extract, which is only not saturated with respect to the constituents to be subsequently added to the roasted coffee and subsequently the constituents are separated in per se known manner.

11. Process according to any one of claims 5 to 8, characterized in that a chlorogenic acid-containing extract is prepared and at least part of the extracted chlorogenic acid is added to the roasted coffee.

12. Process for the production of roasted coffee according to any one of claims 1 to 3, characterized in that isolated chlorogenic acid is added to the roasted coffee.

13. Process for the production of roasted coffee according to claim 3, characterized in that the chlorogenic acid is added to the roasted coffee at least partly in the form of salts.

14. Process for producing roasted coffee according to claim 1, characterized in that the chlorogenic acid is added to the roasted coffee in a quantity such that the roasted product produced therefrom has a chlorogenic acid content of more than 2.8% by weight.

15. Process for producing roasted coffee with a clearly increased chlorogenic acid content, characterized in that by treating raw coffee with a solvent an extract is prepared, the extracted coffee is redried to an average water content, it is reimpregnated with the concentrated extract, redried to the residual moisture content and then roasted.

16. Process for producing roasted coffee according to claim 1, characterized in that a raw coffee with a single origin and/or a single type and/or raw coffee with different chlorogenic acid contents are roasted to a varying degree and from the same a mixture is produced which, compared with a unitary roast, has a much higher chlorogenic acid content and, if necessary, this can be raised to above 2.8% by weight by adding isolated chlorogenic acid.

17. Process for producing roasted coffee according to any one of claims 14 to 16, characterized in that at least part of the raw coffee used undergoes the process according to any one of claims 5 to 8, 13.

18. Process according to any one of claims 5 to 8 or 13 to 16, characterized in that decaffeinated or partly decaffeinated raw coffee is used as the started product or during extraction the caffeine is partly or completely removed from the raw coffee.