FR2593029A1 - PROCESS FOR REMOVING THEOBROMINE AND CAFEINE FROM COCOA BEANS. - Google Patents

Abstract

Process for removing virtually all of the methylxanthines (theobromine and caffeine) normally present in cocoa beans. It consists of subjecting shelled cocoa beans to water extraction at a temperature of about 45 degrees C to about 55 degrees C and then to a series of steps of water extraction at a temperature of about 90 degrees C to about 105 degrees C. The methylxanthines pass through the filtrates and the final fraction freed from methylxanthines is added to the mass of shelled cocoa beans. Field of application: obtaining a cocoa liquor free from methylxanthines.

Description

It has been known for some time that cocoa beans contain a

small amount of caffeine

  (1,3,7-trimethylxanthine) and a considerable amount

  theobromine (3,7-dimethylxanthine).

  The ratio of theobromine to caffeine ranges from about two to one to about ten to one, depending on the particular variety of cocoa beans. In addition, it has been found that theobromine is about 100 times less soluble in water than caffeine. Therefore, the effective removal of these methylxanthines from cocoa beans should primarily involve processes that remove a high percentage of the relatively insoluble theobromine, while at the same time allowing the relatively lower amounts of caffeine to be removed. soluble. The present invention relates to an improved process for the treatment of cocoa beans or shelled cocoa beans for removing methylxanthines, including theobromine and caffeine. These xanthines are members of a broader class of chemical compounds known as purines. The purine system is composed of a

  pyrimidine nucleus and an imidazole nucleus contiguous.

  The nuclei of the purine molecule are numbered starting from the nitrogen atom at the left upper point of the pyrimidine nucleus and advancing counterclockwise to position number 6, then starting clockwise from position number 5 of the pyrimidine ring to obtain positions 7, 8 and 9 in the imidazole ring. Dihydroxy-purines are known as xanthines and are numbered in the same way. This system of nomenclature is used while

  throughout this specification.

  Various methods to achieve elimination

  these cocoa methylxanthines have been proposed previously

  ously. One of these prior methods includes the former

  traction of these methylxanthines using soil

  chlorinated hydrocarbon compounds, such as chloroform, ethylene dichloride or tetrachloroethane. These solvent extraction processes are revealed

  respectively in the United States of America patents

  whereas N 1 073 441, N 1 855 026 and N 1 925 326. However,

  However, the use of these extraction solvents is not recommended, especially when food products are

  these solvents are undesirable in a food product

  silent. Another method of eliminating theobromine from cocoa beans includes extraction with water followed by treatment of the aqueous extract with an adsorbent in divided form. Although this process does not include the use of unacceptable chemicals, such as hydrocarbon solvents

  chlorinated, there are some difficulties related to the use of

  These adsorbent materials have a detrimental effect on the purified cocoa flavor obtained as the final product. In addition, the percentage

  eliminated theobromine is limited.

  Yet another prior method for extracting methylxanthines from a cocoa material is to contact the cocoa material, which has been swelled by treatment with a relatively small amount of water, with a gaseous solvent acceptable in food, such as supercritical nitrous oxide or anhydride

  supercritical carbonic acid. However, this process requires

  long treatment times and frequently does not achieve a sufficient percentage reduction in theobromine content. In addition, the removal of methylxanthines from supercritical gas is a problem when, as is usually the case,

  In this case, we want to reuse the supercritical gas.

  Yet another method of removing caffeine from coffee is disclosed in U.S. Patent No. 4,474,821, in which a countercurrent extraction process using several

  extraction vessels in the counter-operation

  current is revealed. However, in the process of

  this patent, an extraction solvent comprising acetylene

  More ethyl acetate is used in which the ethyl acetate-water azeotrope is finally removed by steam distillation under a pressure difference. In the process of this patent, a turbulent flow of the extraction solvent is used to obtain an accelerated decaffeination rate, which in turn allows the caffeine extraction time to be reduced. This prior process, as well as other

  extraction processes that use organic solvents

  have the disadvantage of requiring contact with the solvent of most of the

  product mass or aqueous extract.

  The present invention relates to a method for

  to virtually eliminate all methylxanthines

  nes present in a cocoa-based material, without using any step having an adverse effect on the final purine-free product, which minimizes the amount of the product

  which is brought into contact with organic solvents

  c. It has been found that the extraction of a cocoa material with water heated to a temperature in the range of about 40 C to about

   C does not eliminate all the methyl-

  xanthines present in a cocoa-based material,

  although this extraction with water is repeated at several

  several times. This is particularly true with regard to the elimination of theobromine in

  residual theobromine content not eliminated

  born is around 1% to 3%. However, it has also been found that elimination is achieved

  greatly improved theobromine if one or more

  if extraction steps with water at a temperature of

  from about 45 ° C to about 55 ° C are followed by several extraction steps with water at a temperature of about 900 ° C to about 105 ° C. It has been found that the use of such extraction by low temperature water followed by a series of water extraction steps at a significantly

  result in the elimination of one percent

  total floor of theobromine much higher than

  that obtained by using each of these temperatures

  erasures of extraction alone. Apparently, the water extraction at a temperature of about 45 ° C to about C changes the content, and perhaps the structure, of the shelled cocoa bean mixture in such a way that the following series of steps extraction with water at a temperature of about 90 ° C to about C allows the elimination of residual theobromine

  not previously removed at each temperature alone.

  The use of a series of high temperature extraction steps not preceded by a low temperature extraction does not eliminate all theobromine. Similarly, the use of low temperature extraction not followed by a series of high temperature extraction steps

  does not eliminate all theobromine. This result

  Surprising and unexpected tat is shown on the charts

  I and II based on results obtained from

  water pulls of shelled cocoa beans

  using different temperatures and stages of ex-

  traction in various numbers. The results of these

  were used to develop respectively the curves of Figures 2 and 3 of the drawings

part of this request.

  The results shown in Tables I and II were obtained as follows:

Example 1

  Four sets of samples each weighing 450 g of raw, vanned and gutted cocoa beans from a bag containing a uniform population were prepared. For each series, the shelled beans were placed inside a stainless steel mesh extraction cartridge.

  N 100 which was then placed in an extrac-

  stainless steel jacketed at temperature

  constant by a water bath with external circulation.

  1400 ml of water were introduced into the extraction tank and the water was stirred continuously through the mass of cocoa beans decorticated by recycling the bottom to the top of the extractor using a recycling pump operating at

  a speed of about 500 ml / min for 20 minutes.

  The first extraction was followed by 7 additional extractions in which 1100 ml of water were added each time to restore the initial volume of liquid. Each of the four series was intended for a particular purpose, as shown by the following: The four series of extraction were performed as follows: 1-a In the first series, the 8 extractions were

were all conducted at 55 C.

  1-b In the second series, the 8 extractions were

were all conducted at 95 C.

  1-c In the third series, three extractions to

   C were followed by 5 extractions at 95 C.

  1-d In the fourth series, three extractions to

   C were followed by 5 extractions at 105 C.

  (To reach the 105 C temperature, the extrac-

  has been maintained at a positive positive pressure

nable).

  The results of the four extractive processes

  are shown in Table I.

TABLE I

  Cumulated quantities of theobromine extracted (g) (grams of theobromine / 450 g of cocoa beans) Number of times

1 2 3 4 5 6 7

  1-a 1t31 2t32 3t12 3167 4.07 4139 4/63 4182 -b 2127 3t72 4ts55 4t96 516 5st24 526 5t27 1-C 1.35 2.37 3t18. 4149 5r27 5t65 5,83 St91 1-d 1,30 2,28 3t05, .4t54 5,37 5sr7 5179 5r84 The significance of the above results is shown by examining the curves shown in Figure 2. The curve corresponding to a temperature of 55 C shows a constant increase in the cumulative quantities of theobromine extracted, the curve stopping well

  below the dashed line after 8 extractions

  tions. The dotted line represents the content

  theobromine theory which can be obtained by using

  a standard AOAC analytical method. The curve corresponding to a temperature of 95 C is clearly flattened after 4 extractions and ends practically

  at the level of the dashed line after 8 extractions

  tions. However, the curve marked 55 C at its end

  lower end and marked 55 C + 95 C at its upper end ends well above the dashed line, thus showing a noticeable increase

  elimination of theobromine when three extractions

  at 55 ° C are followed by 5 extractions at 95 ° C.

Example 2

  The methods of Example 1 were repeated for three sets of extractions, and the three series of extractions were conducted as follows: In the first series, extraction at 55 ° C.

  was followed by seven extractions at 95 ° C.

  2-b In the second series, two extractions at 550C

  were followed by six extractions at 95 C.

  2-c In the third series, three extractions to

   C were followed by five extractions at 95 C.

  The results of the three extraction processes

are shown in Table II.

Table II

  Cumulative quantities of extracted theobromine (g (grams of theobromine / 450 g of cocoa beans) Number of extractions

1 2 2

  2-a-31.3X17 4r43 5t07 5/40 5.55 5t61 Sf64 2-b 1126 2.21 3181 4179 5, 29 5153 5.63 5f67 2-c 1135 2137 3t18 4.49 5127 5.65 5s85 5 The number of extractions may be 1 and 7, or 2 and 6, or 3 and 5, with comparable results. Acceptable results are obtained subject to a temperature of not more than about 55 ° C and not less than about 45 ° C.

the first extraction.

Example 3

  The processes of Example 1 were repeated for seven series of extraction, and the seven series of extraction were conducted as follows: In the first series, three extractions at 40 ° C.

  were followed by 5 extractions at 95 C.

  3-b In the second series, 3 extractions at 50 ° C

  were followed by 5 extractions at 95 C.

  3-c In the third series-, 3 extractions at 55 ° G

  were followed by 5 extractions at 950C.

  3-d In the fourth series, 3 extractions at 60 ° C

  were followed by 5 extractions at 95 C.

  3-e In the fifth series, 3 extractions at 70 ° C

  were followed by 5 extractions at 95 C.

  3-f In the sixth series, 3 extractions at 80 C were

  followed by 5 extractions at 95 C.

  3-g In the seventh series, 8 extractions were

  each at a temperature of 95 C.

  The results of the seven extraction processes

are shown in Table III.

TABLE III

  3-a 3-b 3-c 3 -d 3-e 3-t 3-g Cumulative quantities of extracted theobromine (g) (grams of tho.bromine / 450 g of shelled cocoa beans) shade of extractions 6 0181 1] 44 1t93 3p49. 4146 4F99 5126 '41 lf26 2119 2195.4,43 5t31 5178' 5199 6109 1.40 2.41 3122 4.47 5127 5t68 5X89 5.98

  1I45 2.56 3.42 4149 5117 5S54 5X73 5182

  1.72 2196 3.82 4.71 5123 5.50 5t64 - 5 71 2t03 2.28 3140 4125 4t90- 5.26

3178 4.62 5.03 5.23

, 45 5155 5159

, 32 5136 5.37

  The significance of the above results appears on examining the curves shown in FIG. 3. In this figure, each of the points carried is marked with a number indicating the cumulative quantity in grams of theobromine extracted. The temperatures

  for each of the curves are also indicated.

  In each case, except for the curve corresponding to a temperature of 95 C, two temperatures are indicated. The first temperature concerns the lower portion (3 extractions) of the particular curve and the second temperature concerns the upper portion (5 additional extractions). The experiment illustrates that maximum extraction occurs when the temperature

initial equals 50 C + 5.

  Other features and benefits of this

  invention will emerge from the detailed description which follows,

  with reference to the accompanying drawings in which: - Figure 1 shows a flowchart showing one way of practicing the method of the present invention; FIG. 2 consists of a series of curves on which the results shown in Table I are graphically represented in order to show extractions at low temperature, at high temperature and combined low and high temperature extractions, the number of extractions. being worn and the amount of theobromine extracted being plotted on the ordinate in a rectangular coordinate system. The temperatures for each curve are indicated by means of arrows; FIG. 3 consists of a series of curves on which the results shown in Table III are graphically represented to show the effects of extraction systems at two temperatures, the initial stages operating at

various temperatures.

  A suitable starting point (10) (Fig. 1) for practicing the process of the present invention is to prepare a certain amount of raw shelled cocoa beans obtained from cocoa beans, using conventional methods and well known. In practice, the method of the present invention comprises a series of water extraction steps for separating substantially all water-soluble materials, including caffeine and theobromine, from the initial raw shelled cocoa beans, thereby producing an extract. aqueous shelled cocoa beans and a certain amount of wet shelled cocoa beans. This extraction by water is conducted in a series of stages to two

  very different temperatures: (1) beans

  The extracts are first extracted with water at a temperature in the range of about C to about 55 C. (2) This extraction is followed by extraction at about four or five times

  with water at a temperature within

  from about 90 ° C. to about 105 ° C. After each extraction, the extraction vessel is emptied of substantially all the liquid and the water is

then added.

  Moist shelled cocoa beans (27) remaining after the water extraction steps,

  now virtually all the methyl-

  xanthines and most water-soluble materials are slowly dried (28). Where the content

  the moisture content of the beans reaches a lower

  At approximately 4%, these beans are stored and possibly crushed (29) to obtain a product known as raw cocoa mass (30). In order to obtain a liquid that can be pumped, the mass is crushed again. This mass of raw milled raw cocoa (31) is then ready to be mixed with the solids of the water-soluble material (26).

  which were initially extracted from the beans

  cated. The aqueous extract resulting from the extraction steps is filtered in a filter press (13) or in a decanter by centrifugation to remove small particles. The filtered extract is then subjected to an ultrafiltration step (14) using separation membranes having a molecular weight exclusion of about 10,000 or so.

  000. The filtrate (15) from the membrane con-

  holds more than 97% of the water initially present in the aqueous extract and contains caffeine, theobromine and molecular weight molecules

  less than the exclusion value of the membrane.

  The remaining material is a retained fraction of

  filtration (23) which contains a cocoa-based soluble material having a molecular weight above 20,000. The amount of water is not greater than

  3% of the original volume and contains very small quantities

  caffeine and dethebromin.

  The small amounts of the two methylxanthines

  The dominant moieties remaining in the retained fraction, dimethylxanthine and trimethylxanthine, are minimized by diafiltration (24) which is conducted by adding an equal volume (3% of the original volume) of water to the retained fraction. Then, another equal volume of water is added and the diafiltration process (24) is repeated at least four times. The filtrate of the diafiltration steps is added to the main filtrate (15). The final volume of the filtrate is between about 109 and 115% of the

  initial volume of the extract. The fraction retained

  About 10% cocoa solids are concentrated in an evaporator until the initial volume is reduced to about 1/2 or 1/3. This solution, which is called the final UF retained fraction (25), is now in a form suitable for further processing.

  The material remaining after the filtration step

  (15) contains water-soluble substances of molecular weight less than 20,000 and is subjected to a concentration process (16) in which at least 80% of the water present is eluted by reverse osmosis, which is a known known physical process in industry for concentration of solids and desalination of seawater. Concentrated filtrate (17) containing caffeine, theobromine, cocoa solids

  and water-soluble substances of low molecular weight

  The mixture is subjected to countercurrent extraction (18) with methylene chloride. This countercurrent extraction is based on the partition coefficient of the two methylxanthines between water and methylene chloride. The methylene chloride is recirculated and redistilled at a constant rate in such a manner that it flows through the top-sharing column to the bottom, taking advantage of the density of the methylene chloride solvent. The partition column used in the countercurrent extraction step is maintained at a temperature in the range of about 30 ° C to about 38 ° C. The concentrated filtrate is pumped into the bottom of the feed-through column. equal speed

  at the distillation rate of methylene chloride.

  After caffeine removal greater than 97%, six volumes of methylene chloride must be redistilled for each concentrate filtrate volume, while 18 volumes are required for the same volume of cofluorine.

  yield in the case of theobromine extraction.

  This result can be obtained by increasing the number of reaction columns in series, by recycling the concentrated filtrate in the same columns as required or by proportionally reducing the number of reaction columns.

  flow rate of the concentrated filtrate.

  The concentrated filtrate, resulting from the extrac-

  against the current, is now in the form of a

  fraction (20) disrupts by extraction of methylxanthines.

  Caffeine and theobromine (19) are collected at a high degree of purity in an evaporator after

  the extraction step with methylene chloride.

  The fraction (20) released by extraction of methylxan

  thines is then evaporated under reduced pressure, which makes it possible to eliminate practically all the small residual quantities of solvent. Evaporation is continued until the solids content reaches about 10% by volume. This concentrated material

  is referred to as the final filtrate (21).

  The final filtrate and the final UF retained fraction (25) are then pooled (22). The final solution is then dehydrated (26) by a conventional dehydration technique such as lyophilization or spray drying. The powder thus obtained is added to the ground raw cocoa mass (31), which is then roasted in a grilling apparatus.

  cocoa mass (32) of known design.

  A second possibility is to concentrate the final solution (22) and inject it directly

  in a reactor containing the cocoa mass. The solution

  This is added in several stages, thus allowing the evaporation of the water before roasting of the total cocoa mass in the same reactor. The grilled cocoa mass is equivalent in quality, aroma and functionality to a conventional cocoa liquor but is practically devoid of the stimulants of the type

  xanthine, especially theobromine.

  The description of the overall process above

  is proposed in order to illustrate a way of using the extraction process at many stages of

present invention.

Claims (7)

  A process for removing theobromine and caffeine from cocoa beans, which comprises the steps of subjecting shelled cocoa beans to water extraction.   at a low temperature, within the range of   at 45 ° C., then at a series of high temperature water extraction steps, in the range of about 90 ° C. to about 105 ° C., to remove the extraction filtrates, and then isolating from the cocoa mass thus obtained a cocoa liquor substantially free of theobromine and caffeine. The method of claim 1, further characterized by the introduction of at least one   a water extraction step in the extractive series   at low temperatures and at least three water extraction steps in the extractions series at high temperature.   3. A process according to claim 2, further characterized by carrying out the low temperature extraction step at about 550 ° C and carrying out the high extraction steps. temperature at about 95 C.   4. The process of claim 1   further characterized by the steps of   to put the isolated extraction filtrates at an ultra-   filtration and diafiltration to obtain a fraction retained by ultrafiltration, then to add said retained fraction to the cocoa mass before isolating the cacao liquor freed from theobromine and caffeine.   5. The process of claim 1   characterized further by the steps of eliminating   digest the methylxanthines from the extraction filtrate, then add the fraction freed from the methylxanthines by extraction thus obtained to the cocoa mass before the transformation into cocoa liquor of the mass. of cocoa.   The method of claim 4 further characterized by subjecting   the extraction filtrate from the ultrafiltration steps   filtration and diafiltration at concentration stages.   countercurrent extraction and extraction, and then to add the fraction freed from methylxanthines by extraction with the cocoa mass before the transformation.   cocoa mass in cocoa liquor.   The method of claim 6, further characterized in that it consists in   the reverse osmosis concentration step.