NL8700139A - METHOD FOR REMOVING METHYLXANTHINES FROM COCOA MATERIAL - Google Patents

Description

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Method for removing methylxanthines from cocoa material.

It has been known for some time that cocoa beans contain a small amount of caffeine (1,3,7-trimethylxanthine) and a considerably larger amount of theobromine (3,7-dimethylxanthine). The ratio, which depends on the particular cocoa bean variety, ranges from 5 about 2: 1 theobromine: caffeine to about 10: 1 theobromine: caffeine. In addition, it was found that theobromine is about 100 times less water soluble than coffelne. Therefore, effective removal of these methylxanthines from cocoa beans must be accomplished primarily by methods of removing a large percentage of the relatively insoluble theobromine, while at the same time removing the relatively smaller amounts of more soluble caffeine. The present invention relates to an improved method of treating cocoa beans or broken cocoa beans to remove methylxanthines, consisting of theobromine and caffeine. Such xanthines belong to a much larger class of chemical compounds known as purines. Efetpurine system consists of a pyrimidine ring and an imidazole ring, which are condensed together. The rings of the urine molecule are numbered starting at the nitrogen atom in the top left corner of the pyrimidine ring and progresses anti-clockwise to the 6 position and then clockwise from the 5 position in the pyrimidine ring to obtain the 7-, 8- and 9th place in the imidazole ring. The dihydroxy purines are known as xanthines and are numbered in the same way. This nomenclature system is used throughout the present specification.

Various methods of removing such methylxanthines from cocoa material have so far been proposed.

One such known method involves the extraction of these methylxanthines with chlorinated hydrocarbons, such as chloroform, ethylene dichloride or tetrachloroethane. Such solvent extraction processes are described in U.S. Pat. Nos. 1,073,441, 1,855,206, and 1,925,326, respectively. However, the use of such extraction solvents is not recommended, especially in the case of foodstuffs as residues. from .

Such food solvents are undesirable. Another method of removing theobromine from cocoa beans - 2 - involves extraction with water, followed by treatment of the aqueous extract with an adsorbent in finely divided form. Although no undesirable chemicals, such as chlorinated hydrocarbons, are used in this process, there are certain difficulties associated with the use of such adsorbents, which adversely affect the taste of the final dewaxed cocoa product. In addition, the percentage of theobromine removed is limited.

Yet another known method of extracting methylxanthines from cocoa material involves contacting the cocoa material, which has been swollen by treatment with a relatively small amount of water with a food-acceptable dissolving gas, such as supercritical nitrogen oxide or supercritical carbon dioxide. However, this method requires long treatment times and often provides insufficient percentage reduction of the theobromine content. In addition, the removal of the methylxanthines from the supercritical gas presents a problem if, as is usually the case, it is desired to reuse the supercritical gas.

Yet another method of removing caffeine from coffee is described in U.S. Patent No. 4,474,821, which describes a countercurrent extraction process using a plurality of countercurrent extraction vessels. However, the method of this patent uses an extraction solvent consisting of ethyl acetate plus water, the ethyl acetate-water azeotrope being finally removed by differential pressure steam stripping. The process of this patent employs a turbulent flow of the extracting solvent to obtain accelerated decaffeination, which in turn shortens the extraction time. This known process, like other extraction methods using organic solvents, has the disadvantage that it is necessary to expose most of the product mass or water extract to the solvent.

The present invention relates to a process for removing almost all methylxanthines present in cocoa material, without taking any measures, which has an adverse effect on the final product de-purified and the amount of final product which is converted to organic solvents. exposed to a minimum. It was discovered that 87 0 013 9 * 3 - 3 extraction of cocoa material with water at 40-60 ° C does not remove all methylxanthines present in cocoa material, even if such an extraction with water is repeated many times. This is especially true for the removal of theobromine, because the residual theobromine, which has not been removed, is on the order of 1-3%. However, it has also been found that the removal of theobromine can be greatly improved if one or more extraction steps with water at about 45-55 ° C are followed by some extraction steps with water at about 90-105 ° C. It has been found that using such an extraction with water at a low temperature followed by a series of extraction steps with water at a significantly higher temperature results in a much higher percentage of total theobromine removed than using any of these extraction temperatures alone. Apparently, the extraction with water at 45-55 ° C IS changes the content and possibly the structure of the broken cocoa bean mixture such that the subsequent series of extraction steps with water at 90-105 ° C removes residual theobromine, which used to be at either temperature only was not removed. The use of a series of high temperature extraction steps, which is not preceded by a low temperature extraction, does not remove all theobromine. Also, when using a low temperature extraction, which is not followed by a series of high temperature extraction steps, not all theobromine is removed. This surprising and unexpected result is shown in Tables A and B, which are based on data obtained from water extraction of broken cocoa beans using different temperatures and numbers of extraction steps. The data from these tables have been used to draw up the curves of Figures 2 and 3, respectively, which are included here.

30 The data reported in Tables A and B were obtained as follows:

Example I

Four aliquots of 450 g of raw, walled and germinated crushed cocoa beans were each prepared from a bag of uniform composition. Each of these amounts of crushed cocoa beans was placed in a 100 mesh stainless steel extraction stocking, which was then placed in a jacketed stainless steel extractor, which was kept at constant temperature by an externally circulating water bath. 1400 ml of water was introduced into the extraction reservoir and the water was stirred continuously through the crushed cocoa bean mass by recirculation from bottom to top into the extractor 5 using a recirculation pump operating at 500 ml per minute for 20 minutes. The first extraction was followed by a further 7 extractions, 1100 ml of water each being added to restore the original liquid volume. Each of the four quantities had a specific purpose, as evidenced by the following:

The four aliquots were extracted as follows: 1a. In the first batch, all extractions were performed at 55 ° C.

lb. In the second batch, all extractions were performed at 1595 ° C.

lc. In the third aliquot, three extractions at 55 ° C were followed by five extractions, at 95 ° C.

ld. In the fourth batch, three extractions at 55 ° C were followed by five extractions at 105 ° C. (To obtain the temperature of 105 ° G, the extractor was kept at an appropriate gauge pressure.)

The results of the extractions of the four amounts are given in Table A.

Table A

25 Total extracted theobromine (g) (g theobromine / 450 g broken cocoa beans) _Number of extractions_ 1 2 3 4 5 6 7 8 1-a 1.31 2.32 3.12 3.67 4.07 4.39 4.63 4.82 30 1-b 2.27 3.72 4.55 4.96 5.16 5.24 5.26 5.27 1-c 1.35 2.37 3.18 4.49 5.27 5 , 65 5.83 5.91 1-d 1.30 2.28 3.05 4.54 5.37 5.67 5.79 5.84

The significance of the above results is apparent from examination of the curves shown in Figure 2. The 55 ° C curve shows an ever-increasing rise in the total amounts of theobromine extracted, while the curve ends well below the dotted line after 8 extractions. The dotted line represents the theoretical theobromine content, which can be obtained under 87 0 013 0 - 5 - 4 using a standard AOAC analysis method. The 95 ° C curve is remarkably smoothed after 4 extractions and ends almost at the dotted line after 8 extractions. However, the curve, denoted 55 ° C at the bottom and 55 ° C + 95 ° C at the top, ends 5 well above the dotted line and thus shows a significant increase in theobromine removal when 3 extractions are followed at 55 ° C by 5 extractions at 95 ° C.

Example II

The operations of Example I were repeated with 3 extraction amounts, which were treated as follows: 2a. In the first batch, one extraction at 55 ° C was followed by seven extractions at 95 ° C.

2b. In the second batch, two extractions at 55 ° C were followed by six extractions at 95 ° C.

15 2c. In the third batch, three extractions at 55 ° C were followed by five extractions at 95 ° C.

The results of the three extractions are shown in Table B.

Table B

20 Total extracted theobromine (g) (g theobromine / 450 g broken cocoa beans) __________Number of extractions__ 1 2 3 4 5 · 6 7 8 2-a 1.31 3.17 4.43 5.07 5.40 5.55 5, 61 5.64 25 2-b 1.26 2.21 3.81 4.79 5.29 5.53 5.63 5.67 2-c 1.35 2.37 3.18 4.49 5.27 5.65 5.85 5.91

The number of extractions with comparable results could also be 1 and 7 or 2 and 6 or 3 and 5. Acceptable results are obtained if the first extraction temperature is not higher than 55 and not lower than 45 ° C.

Example III

The operations of Example I were repeated for seven extraction amounts, which were treated as follows: 3a. In the first batch, 3 extractions at 40 ° C were followed by 5 extractions at 95 ° C.

3b. In the second batch, 3 extractions at 50 ° C were followed by 5 extractions at 95 ° C.

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IS »- 6 - 3c. In the third amount, 3 extractions at 55 ° C were followed by 5 extractions at 95 ° C.

3d. In the fourth batch, 3 extractions at 60 ° C were followed by 5 extractions at 95 ° C.

5 3rd. In the fifth amount, 3 extractions were made at 70 ° C

followed by 5 extractions at 95 ° C.

£ 3. In the sixth amount, 3 extractions at 80 ° C were followed by 5 extractions at 95 ° C.

3g. In the seventh amount, 8 extractions were each performed at 95 ° C.

The results of the seven extractions are shown in Table C.

Table C

Total extracted theobromine (g) 15 (g theobromine / 450 g broken cocoa beans) _Number of extractions_ 1 2 3 4 5 6 7 8 3-a 0.81 1.44 1.93 3.49 4.46 4.99 5.26 5.41 3-b 1.26 2.19 2.95 4.43 5.31 5.78 5.99 6.09 20 3-c 1.40 2.41 3.22 4.47 5.27 5 .68 5.89 5.98 3-d 1.45 2.56 3.42 4.49 5.17 5.54 5.73 5.82 3-e 1.72 2.96 3.82 4.71 5.23 5.50 5.64 5.71 3-f 2.03 3.40 4.25 4.90 5.26 5.45 5.55 5.59 3-g 2.28 3.78 4. 62 5.03 5.23 5.32 5.36 5.37 The significance of the above results can be seen from an examination of the curves shown in Figure 3. In this figure, each of the plotted points is numbered, indicating the total amount of theobromine extracted in grams. The temperatures are also indicated for each curve. Two temperatures are indicated, except for 30 at the 95 ° C curve. The first temperature refers to the lowest part (3 extractions) of the curve in question and the second temperature refers to the highest part (5 more extractions). The test shows that maximum extraction occurs when the initial temperature is 50 ° + 5 ° C.

35 Brief description of the figures.

Figure 1 consists of a flow chart showing one method of carrying out the method of the invention.

Figure 2 consists of a series of curves which graphically plot the data 8700139 »* - 7 - of Table A to show extraction at low temperature-1 temperature and a combination of low and high temperature, plotting the number of extractions on the ordinate and the amount of theobromine extracted is plotted on the abscissa of a rectangular coordinate system. The temperature applicable to each curve is indicated by arrows.

Figure 3 consists of a series of curves graphically plotting the data of Table C to show the effects of extraction systems operating at two temperatures, the lowest temperature being different for each extraction system.

Preferred Conditions for Carrying Out the Invention.

A good starting point (10) (Figure 1) for carrying out the method of the invention consists in preparing an amount of raw crushed cocoa beans, obtained from cocoa beans, using known standard methods. Practically speaking, the method of the invention consists of a series of extractions with water which separate almost all water-soluble substances, including caffeine and theobromine, from the original raw crushed cocoa beans, to obtain an aqueous extract of the broken cocoa beans and an amount of wet broken cocoa beans. This extraction with water is performed in a series of steps at two very different temperatures: (1) the crushed cocoa beans are first extracted with water at 45-55 ° C and (2) this is followed by about four or five times extraction at 90-105 ° C. After each extraction, almost all liquid is drained from the extraction vessel and then water is added.

The wet crushed cocoa beans (27) which remain after the extractions with water and which are now substantially depleted of all methylxanthines and most water-soluble substances, are dried slowly (28). When the moisture in the broken cocoa beans reaches a point below about 4%, they are collected and finally ground (29) to yield a product known as raw cocoa mass (30). In order to obtain a pumpable liquid, the mas-35 sa is ground again. This is again ground raw cocoa mass (31).

ready for mixing with the solids of the water-soluble material (26), which were initially extracted from the crushed cocoa beans.

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The water extract obtained from the extractions is filtered to remove small particles in a filter press (13) or in a centrifugal clarifier. The filtered extract is then ultrafiltrated (14) using separating membranes with a cut molecular weight of about 10,000 or about 20,000. The filtrate (15) from the membrane contains more than 97% of the water originally in the water extract was present and contains caffeine, theobromine and molecules smaller than the cutoff value of the membrane. The remaining material is an ultrafiltration retentate (23) containing soluble cocoa material with a molecular weight higher than 20000. The water is no more than 3% of the original volume and contains very small amounts of caffeine and theobromine.

The small amounts of the two main methylxanthines that remain in the retentate, namely dimethylxanthine and trimethylxanthine, are minimized by diafiltration (24), which is carried out by adding an equal volume (3% of the original) water to the retentate. Then an equal volume of water is added and the diafiltration process (24) is repeated at least four times. The filtrate from the diafiltrations is added to the main filtrate (15). The final volume of the filtrate is 109-115% of the original volume of the extract. The retentate, which contains about 10% cocoa solids, is concentrated in an evaporator until the original volume is reduced to about one-half or one-third.

This solution, eventually called UF retentate (25), is now suitable for further processing.

The material remaining after the filtration (15) comprises water-soluble substances with a molecular weight of less than 20,000 and is subjected to a concentration process (16), whereby at least 80% of the water present is removed by reverse osmosis, which is a known physical operation, which is available in industry for solids concentration and seawater desalination. The concentrated filtrate (17), containing caffeine, theobromine, cocoa solids and low molecular weight water-soluble substances, is subjected to countercurrent extraction (18) with methylene chloride. This countercurrent extraction is based on the partition coefficient of the two methylxanthines between water 8700139-9-methylene chloride. The methylene chloride is recirculated and redistilled at a constant rate such that it circulates in the distribution column from top to bottom, taking advantage of the specific gravity of the methylene chloride. The distribution column used in the countercurrent extraction is kept at 30-38 ° C. The concentrated filtrate is pumped from below into the distribution column at a rate equal to the distillation rate of the methylene chloride. In order to achieve a better removal of caffeine than 97%, 6 volumes of methylene chloride must be redistilled for every volume of concentrated filtrate, while 18 volumes are required for the same efficiency in the extraction of theobromine. This result can be obtained by increasing the number of active columns in series, by recycling the concentrated filtrate into the same columns as required or by proportionally decreasing the flow rate of the concentrated filtrate.

The concentrated filtrate from the countercurrent extraction is now in the form of a fraction from which methylxanthine has been extracted (20). Caffeine and theobromine (19) are recovered in a high degree of purity from an evaporator connected after the methylene chloride extraction. The fraction from which methylxanthine has been extracted (20) is then evaporated under reduced pressure, removing almost all minor solvent rights. Evaporation is continued until the solid content has reached 10 volume%. This concentrated material is referred to as final filtrate (21).

The final filtrate and the final UF retentate (25) are now combined (22). The combined final solution is then dried (26) by a conventional drying method, such as freeze drying or spray drying. The powder thus obtained is added to the reground raw cocoa mass (31), which is then roasted in a cocoa mass roaster (32) of known design.

A second optional possibility is concentration of a combined final solution (22) and direct injection of this solution into a cocoa mass reactor. The solution is added in several steps, thus evaporating the water to burn the entire cocoa mass in the same reactor. The roasted cocoa mass is equivalent in quality, taste and effect to ordinary 8700139

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- 10 - cocoa liquor, but is practically free from stimulant xanthines, in particular theobromine.

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Claims (7)

Process for removing theobromine and co-fexne from cocoa beans, characterized in that crushed cocoa beans are subjected to extractions with water at low temperature at 45-55 ° C and then to a series of extractions with water at high temperature at 90 DEG-105 DEG C., the extraction filtrates are removed and then cocoa liquor which is substantially free of theobromine and caffeine is recovered from the thus accrued cocoa mass. 2. Process according to claim 1, characterized in that at least one extraction with water at low temperature and at least three extractions with water at high temperature are carried out. 3. Process according to claim 2, characterized in that the extraction at low temperature at 55 ° C and the extractions at high temperature at 95 ° C are carried out. 4. Process according to claim 1, characterized in that the removed extraction filtrates are subjected to ultrafiltration and diafiltration to obtain an ultrafiltration retentate and this retentate is then added to the cocoa mass before the cocoa liquor is extracted from the cocoa mass, from which theobromine and cofilm are extracted to be. 20 Process according to claim 1, characterized in that methylxanthines are removed from the extraction filtrate and then the fraction thus obtained, from which methylxanthine has been extracted, is added to the cocoa mass before the cocoa mass is processed into cocoa liquid. 25 Process according to claim 4, characterized in that the extraction filtrate of the ultrafiltration and diafiltration is concentrated and subjected to countercurrent extraction and then the fraction from which methylxanthine has been extracted to the cocoa mass before processing the cocoa mass into cocoa liquid. 30 Process according to claim 6, characterized in that the concentration is carried out by reverse osmosis. - o - o — o - o - o - o - o - 870 01 39