WO1997033484A1 - Drying method for cacao beans - Google Patents

Abstract

A method for improving the cocoa flavour obtained from beans of the cocoa plant Theobroma cacao in which the beans are at least partially deshelled prior to the drying step.

Description

DRYING METHODFORCACAOBEANS

The present invention relates to method of reducing levels of acidity in fermented beans of the cocoa plant Theobroma cacao prior to drying of the beans, to improve and enhance the cocoa flavour of such beans.

The beans of the cocoa plant ( Theobroma cacao) are the raw material for cocoa, chocolate and natural cocoa and chocolate flavouring. As described by Rohan ("Processing of Raw Cocoa for the Market", FAO/U (1963)) , raw cocoa beans and extracted from the harvested cocoa pod, from which the placenta is normally removed, the beans are then "fermented" for a period of days, during which the beans are killed and a purple pigment is released from the cotyledons. During fermentation "unknown" compounds are formed which on roasting give rise to characteristic cocoa flavour. Rohan suggests that polyphenols and theobromine are implicated in the flavour precursor formation. After fermentation, the beans are dried, during which time the characteristic brown pigment forms, and they are then stored and shipped.

Fresh cocoa beans contain 35%-45% moisture according to Rohan. An analysis in Rohan of dried unfermented West African cocoa beans showed that the moisture content was 3.65%, the level of tannins (which includes the polylphenols) was 7.54% and the level of theobromine was 1.71%. Cocoa pulp at pH 3.3 is an ideal medium for the formation of alcohol and organic acids by fermentation. The organic acids in their unionised form are able to cross membrane barriers and so enter the beans where they encounter a pH of 6.5 and ionise immediately. The resulting flood of hydrogen ions kills the living cells in the beans by disrupting their normal energy and transport mechanisms. Enzyme/substrate reactions, which under normal conditions would result in the ordered development of a cocoa seedling, progress chaotically to produce cocoa flavour precursors from which the characteristic flavours of cocoa are derived during the roasting process.

During drying, excess acids diffuse from the beans to the shells where they are lost either by evaporation or by microbial decomposition. If the beans are dried too quickly, water evaporates ahead of the rate of diffusion leading to an unacceptably high concentration of residual acids in the beans. When the beans are roasted to produce cocoa flavour, high levels of residual acids either mask any cocoa flavour that is formed or impede the desired flavour-forming reactions. Either way, the cocoa tastes sharp and acid with very little true cocoa flavour, which is typical of most of the cocoa produced in Malaysia, Indonesia and other cocoa origin countries where hot air dryers are used. In West Africa on the other hand, most of the fermented cocoa is spread out under the sun to dry, which may take up to 5 or 6 days. Much lower levels of residual acidity are achieved and more cocoa flavour is produced from West African beans on roasting. Whereas sun drying is easily managed in West Africa where a million or more cocoa farmers may each produce no more than a few bags (62.5 Kg) of cocoa per annum, it is impractical for estate-scale production where up to 40 metric tonnes of dry beans are produced each day during peak crop seasons.

At present cocoa beans are dried either artificially in a current of hot-air, in the cocoa producing countries of South East Asia, or by spreading out the cocoa beans in the sun to dry in the cocoa producing areas of West Africa.

The present processes for drying cocoa beans are, however, unable to deliver large amounts of good quality cocoa flavour either because the process is inherently inefficient and cannot conveniently be scaled up (sun- dried method) or because the means used to dry the beans produces high levels of acidity which mask or impair the cocoa flavour produced (hot-air drying method) .

It is speculated that organic acids alone are responsible for the sharp or acid taste of cocoa produced by the hot- air drying method. However, it is thought unlikely that the organic acids themselves account for the excessively acid taste, even though they may ultimately be responsible for it, as there are probably not enough of them formed during pulp formation. Furthermore, cocoa flavour intensity and astringency have been negatively correlated, which suggests that the polyphenols responsible for astringency might be the cocoa flavour precursors. If the enzymatic conversion of polyphenols to cocoa flavour were inhibited in an acidic environment then excess acid would be indirectly rather than directly responsible for poor flavour quality, the sharp taste being a combination of acidity and astringency rather than acidity alone.

The present invention seeks to provide a solution to these problems by providing a means for producing enhanced and improved cocoa flavour from cocoa beans on a commercially useful scale. Whether or not the speculation set out in the last preceding paragraph is correct, it has been found that the flavour of cocoa can be improved by the following method.

According to a first aspect of the present invention, there is provided, a method of processing beans of the cocoa plant Theobroma cacao, the method comprising at least partially deshelling, and subsequently drying, the beans.

In the present application, the term "shell" is used to describe the seed coat or testa of the cocoa bean. The dried testa may also be more precisely known as a "hull" or a "husk" .

While the invention primarily relates to the processing of the beans of the major cocoa plant species, Th . cacao, the invention is not limited solely to this species and includes the subspecies Th . cacao cacao and Th . cacao sphaerocarpum. For example, many cocoa varieties are hybrids between different species; an example of such a hybrid is the trinitario variety.

The invention involves at least partially deshelling cocoa beans. The shells may be partially removed or even merely opened. In some cases it may be desirable fully to remove the shells of the beans processed according to the method. There is also evidence of flavour improvement if the shell is simply broken to provide an exposed surface of nib which may allow the organic acids to escape. It might not be necessary therefore to separate nibs from shells completely before drying.

The term "nib" is used in the present application to describe a partially or wholly deshelled bean. The term may also describe a bean which has been deshelled and then broken into fragments. Where the bean remains whole after removal of the shell, it may also described by the term "cotyledons" .

The removal or opening of the shell of the cocoa beans may be achieved by any suitable method, which may be mechanical or chemical .

Examples of mechanical techniques, which may be manual or may be automated using appropriate apparatus, include scoring, scraping, cracking, crushing and/or winnowing. Examples of suitable machines include a rubber creping machine and a custom-built rotating bed of nails. The shells of the cocoa beans can also be removed manually but this is not an economically realistic method. Residual shell particles from beans which have been partially deshelled or opened could be removed by winnowing before or after the broken beans have been dried and/or roasted.

An example of a chemical technique is lye-peeling. Lye- peeling is commonly used for vegetable and fruit peeling and may also be suitable for use in the present invention. Lye-peeling involves the use of an alkali treatment of fruit to remove the skins prior to canning.

Deshelled beans or nibs are then suitably dried to produce the cocoa flavour. The drying process may be carried out in a stream of air which is at an ambient temperature of from 15°C to 35°C, suitably 20°C to 30°C and preferably 25°C. The drying at an ambient temperature may be carried out for a period of from 2 to 72 hours, suitable of from 4 to 48 hours and preferably of from 16 to 24 hours. The process may also be suitably carried out under conditions of ambient humidity. This is then followed by drying with air heated to a temperature of from 45°C to 75°C, suitably 50°C to 65°C, more preferably 60°C to bring the beans to total dryness. Drying at the higher temperature may be for a period of from 1 to 12 hours, suitably of from 2 to 8 hours and preferably of from 4 to 6 hours . Acceptable results can also be obtained by drying the deshelled beans or nibs at an ambient temperature alone of from 15°C to 35°C, suitably 20°C to 30°C and preferably 25°C.

While the method of the invention primarily has application to air drying processes, as typically practised in South East Asia, it may also be used with advantage in conjunction with sun drying processes as typically used in West Africa. However, it is in the air drying process that the greatest improvement in cocoa flavour may be achieved.

While it has been stated above that the drying step is subsequent to the deshelling step, it should be understood that a certain amount of drying prior to the deshelling step can be tolerated, even if it is not particularly advantageous to put the invention into effect in this way. The important point is that enough of the overall drying process should take place after the deshelling step to enable the advantage of the invention to be achieved.

There are circumstances, however, when some pre-drying is advantageous. It has been found, for example, that if the skin of the cocoa beans is at least partially dried prior to deshelling, the breaking of the shells may be facilitated under conditions of ambient temperature and/or ambient humidity (the term "skin" is used to describe the shell of the cocoa bean when the shell is wet) . This step may for a time period of from 30 minutes to 6 hours, suitably of from 1 hour to 4 hours and preferably for 1 hour. The precise time period to be used will depend on the amount of beans to be dried and can be determined by the skilled person in the art without any undue burden. Provided that the temperature of the cotyledons does not rise above the levels encountered during fermentation then the enzymic modifications of the cotyledons, which are believed to be responsible for the flavour improvement during final drying, are unlikely to be affected.

Additionally, the method may advantageously contain a primary washing step, prior to the drying and deshelling steps. The removal of mucilage may facilitate the subsequent breaking of the shells and separation of nibs and testa.

After drying, roasted or unroasted nibs can be used for production of cocoa liquors in the normal way or for the production of cocoa butter and cake by filter pressing (of liquor) or by expelling. In general, fermented cocoa beans, dried by the sun or hot-air methods, are normally packed in jute sacks for storage and transportation. Whole beans are traditionally subjected to a roasting treatment to develop flavour at temperatures, typically between 110-150°C. The roasting treatment may be preceded by a process, such as micronising, which facilitates shell removal by winnowing, or winnowing may be carried out after completion of the roasting stage. In either case, the final product of the roasting and winnowing treatments is roasted cocoa nibs, which are then traditionally ground to produce cocoa liquor. Cocoa liquor may be used directly as an ingredient in chocolate recipes (formulations) , or may be separately processed further, by filter pressing, to produce cocoa butter and cocoa cake. Cocoa cake is subsequently milled to produce cocoa powder. In the expelling process, dried beans, with or without a shell or part thereof, are put through a screw press expeller to produce cocoa butter and cake.

The improved cocoa flavour produced by the method of the present invention compared to that obtained by simply treating the beans by the hot-air methods typically used at present is characterised by the flavour having a greater level of cocoa flavour but a reduced level of acidity, bitterness and astringency.

Cocoa flavour may be classified according to the following categories: cocoa flavour, acid/sharp, astringent, bitter, raw/green, fragrant/floral, brown fruit, late sour and thick mouthfeel . Scores may be assessed on a point system and a high score in a category indicates a strong intensity for a particular flavour.

As mentioned above, it is possible that the beneficial results of the invention are achieved because the partial deshelling results in a reduction of the level of acidity in the bean.

According to a second aspect of the present invention, there is provided a method of reducing levels of acidity in fermented beans of the cocoa plant Theobroma cacao to improve cocoa flavour in which the cocoa bean are partially deshelled, prior to drying the beans, such that the organic acid level in the beans is reduced. Other preferred aspects of the second aspect of the present invention are as for the first aspect mutatis mu andis.

The invention will now be described by way of example with reference to the accompanying Examples which are provided for the purposes of illustration and are not to be construed as being limiting on the present invention.

Example 1: Manual deshelling of beans

Fermented beans, deshelled manually, were dried either under the sun or in a current of air at ambient temperature or at 40°C. All were dry within 48 hours and produced cocoa liquors which were less acidic and astringent and had more pronounced cocoa flavour than corresponding liquors produced from whole beans dried for the same period of time at 60°C.

First attempts to separate broken shells from nibs used a sink/float process with a solution of sugar in water or a suspension of inert material (limestone or clay) to form a density of gradient. Although reasonably successful on a laboratory scale this was not practicable for commercial scale production.

Example 2; Manual deshelling of beans and expeller trial

1 tonne of fermented beans was deshelled by hand in order to provide enough deshelled dried beans for an expeller trial. The deshelled beans were sun-dried and put through a screw press expeller. Satisfactory samples of cocoa butter (considered acceptable for direct use without deodorisation) and cake were obtained. Example 3: Mechanical deshelling of beans using rotating bed of nails

A device on which beans were cut and torn between a fixed and rotating bed of nails was constructed to provide 50 Kg samples of deshelled nibs for further trials. Deshelled nibs were dried in a current of air at ambient temperature for 16 hours and then at 60°C to final dryness. Flavour profiles of cocoa liquors made from the deshelled nibs, whole beans dried at 60°C throughout and whole beans subjected to the same drying treatment as the deshelled nibs are shown below. The liquor from the deshelled nibs had more cocoa flavour and was less acidic, bitter and astringent than those from the whole beans. The reduced astringency, late sour taste and increased viscous/thick mouthfeel are indicative of changes in the polyphenol chemistry effected by the removal of the shells prior to drying. Cocoa liquors from the deshelled nibs were also much darker in colour.

Table 1

Whole beans at 60°C Whole beans 16/60°C Deshelled nibs 16/60°C

Cocoa flavour 4.6 4 6.4

Acid/sharp 4.2 4 2.6

Astringent 5.1 5.1 3.5

Bitter 4.3 4.8 3.4

Raw/green 3.7 3.8 2.3

Fragrant/floral 3.9 3.4 4.4

Brown fruit 2.9 2.6 4.5

Late sour 3.3 4.7 2.9

Thick mouthfeel 3.4 3.8 5.3 The three drying treatments used were (i) whole beans dried at 60°C throughout, (ii) whole beans 16/60°C - dried in a current of air at ambient temperature for 16 hours then at 60°C to final dryness, (iii) deshelled nibs 16/60°C were dried likewise as (ii) . Scores on 10 cm line scale. Higher scores denote stronger intensities. The improvements in flavour have been confirmed in further trials. Cocoas have been tasted as cocoa liquors and as plain chocolates.

Example 4 : Mechanical deshelling of beans using rubber creping machine (no pre-washing step and no skin drying step)

Fermented beans have also been put through a rubber creping machine. A spacing of 3/16 of an inch between the rollers rotating at slightly different speeds tears the beans while leaving larger pieces of shell intact. The debris is dropped onto a rapidly rotating cone which throws it onto a screen sieve. Pieces of nib pass through the screen. Larger pieces of shell are retained for recycling until the degree of separation of nib and shell fragments is satisfactory. The efficiency of both bean breaking on the creping machine and separation of nibs and shells is improved by prior treatment of the fermented beans with a pectolytic enzyme to remove excess mucilage.

Example 5: Mechanical deshelling of beans using rubber creping machine with pre-washing step and skin drying step

Beans straight from the fermentation box were paddled mechanically under running water for 10 minutes to remove residual mucilage and are then skin dried at 60°C for up to 60 minutes depending on the bed depth. Removal of mucilage and skin drying facilitates subsequent breaking of the beans and separation of nibs and testa.

Provided that the temperature of the cotyledons does not rise above the levels encountered during fermentation, the enzymic modifications of the cotyledons, which are believed to be responsible for the flavour improvements during final drying, are unlikely to be affected.

The skin dried beans were then broken manually or by putting them through the rollers of a machine used to crepe latex (known as a rubber creping machine) . The stainless steel rollers, which have diamond cut surfaces and are at a gap setting of 3/16", rotate at slightly different speeds and so cut, crush and tear the beans.

The debris comprising broken nibs and shells (testa) was then dried in a current of air by one of two procedures.

The current of air was either passed through the debris in a box with a base of fine metal or nylon gauze, or the current of air was passed over the debris spread out in thin layers on trays.

The dried debris was roasted, crushed lightly to remove any adhering shells from nibs and winnowed to separate the nibs and shells. Roasted nibs containing less than the statutory 1.5% shell were finally milled into cocoa liquor. Example 6: Effects of different drying treatments

Comparative example 6 (a)

The previous standard treatment used to dry whole beans is to dry the beans in a current of hot air at 60°C for 48 hours which results in beans with a whole bean moisture content of 7.5%.

Although washed beans, subjected to the above conditions of hot bed drying, gave slightly better flavour than unwashed beans, the flavour improvement, while being directionally similar, was much less pronounced than when the beans were broken to expose the nibs prior to drying, i.e. as in treatments described in examples 6(b), 6(c) , 6(d) , 6(e) , 6(f) and 6(g) below.

Example 6 (b)

Two kilogram samples of broken beans were dried by burying them in nylon net bags in the mass of whole beans on the hot air dryers using the standard air temperature of 60°C. The bags were inserted towards the end of the 48 hour period of drying when the bulk mass of beans was drier than the broken beans, which therefore did not absorb any moisture from the whole beans.

The broken beans were dry (approximately 5% nib moisture) after 4 hours and gave distinctly better flavour (less acid/sour, acrid, bitter and astringent) than a 2 kg coned and quartered sample from the mass of beans which originated from the same mixed planting materials and with the same fermentation history but dried for 48 hours on the hot bed dryers, i.e. in comparative example 6(a) above. Example 6 (c)

Flavour was further improved by drying the broken beans in a current of air at ambient temperature for 16 hours and then for a further period of up to 4 hours at 60°C, as above, to 5% nib moisture. In these trials the broken beans were dried at about 4 cm bed depth in boxes with a fine wire mesh (mosquito net) based and solid sides, inserted in bulk samples of fermented beans being dried at about 12 to 18 inches bed depth on flat bed dryers. This example used a "high" velocity air flow to dry the cocoa beans.

The beds were dug out so that the boxes could be inserted with the mesh base in direct contact with the perforated floor of the drying platform. The heat source to the drying bed was turned off one hour before the boxes were inserted. If the bulk beans on the drier were still wet and/or deep, most of the air onto the drier was channelled through the thin layer of broken beans in the boxes, that being the point of least resistance. The flow rates of air through the broken beans were estimated at between 15 and 30 cubic metres per minute. Under these conditions the broken beans dried very quickly. Draeger tube estimates of acetic acid concentration showed that acid low was rapid also - from about 40ppm at time zero, the acetic acid concentration had dropped to lOppm after only 4 hours before reaching a limiting concentration of less than 5ppm after 16 hours.

There was very little difference in flavour between broken beans dried at 60°C throughout under these conditions and samples taken after 4, 8, 12 and 16 hours ambient drying under these conditions prior to final drying at 60°C. There is obviously more to the process than the rapid removal of acid. If indeed the flavour improvement results from the enzymic modification of the nibs under conditions of reducing acidity, then the enzymic reactions will need time to progress and may do so only when the nibs remain sufficiently moist. Fast drying whole beans at high temperatures might have 3 possible disadvantages - acidity is retained, the higher temperature deactivates the enzymes involved and the beans dry too quickly.

Example 6 (d)

In this example a diesel fuelled drier with plentiful supplies of palm kernel shells for solid fuel burners was used. The bed was covered with jute (gunny) sacks to direct a much reduced air flow through the broken beans in boxes which occupied a tiny proportion of the total drying area. When the powerful fan was switched on to blow air at ambient temperature, the sacking covering the floor billowed like a thin carpet on a draughty floor and the air flow through the broken beans was reduced to 5 to 10 cubic metres per minute.

Under these conditions the acetic acid concentration, starting again at 40 ppm was reduced to only 28ppm after 5 hours and had reached the limiting concentration of less than 5 ppm after between 20 and 24 hours. It was noticeable that the nibs which were still appreciably moist were much darker in colour than those from treatment in example 6(c) .

Cocoa liquors had much more cocoa flavour, were less astringent and were darker in colour and more viscous than all previous samples from the present trials. The rate of drying was reduced still further by increasing the bed depth of broken beans in the boxes to 8cm. The flow rate was then about 3 cubic metres per minute initially rising gradually to about 7 as the beans dried and offered less resistance to air flow through the boxes.

Example 6(e)

Prior to example 6 (d) , and while recognising that considerably more flavour improvement was needed, it was decided to test the flavour stability of dried nibs.

Plain chocolates were made from nibs from example 6(c) . Half of the chocolates were kept in a fridge and the other half at room temperature (air conditioned) . After preparation of the first batches of chocolate, the nibs were divided and stored, one portion deep frozen and another at ambient temperature. One week later further batches of chocolate were made from nibs from the two storage conditions. The chocolates were stored as before and were allowed to condition for at least 4 days from the time of preparation before tasting.

Whereas there were no appreciable differences in flavour between chocolates from the same batch stored in the fridge or at room temperature, there was a marked deterioration in the flavour of chocolates made from nibs stored for 1 week at ambient temperature. A rancid fat and bitter note had developed.

This began to fit in with a common but ill defined off- flavour that had been observed throughout the course of the work. It was described as "wheaty" and it had been observed when the new drying process was applied in the MARS laboratory in Kuala Lumpur. It was also described as "rancid fat" or "cereal". The note was particularly pronounced in deshelled beans which had been sundried.

It had also been noticed that dried nibs developed a whitish appearance during storage which at first was feared to be mould growth but was later recognised as fat bloom. The bloom disappeared on holding the nibs in a clenched fist for a few minutes or after placing the nibs in a warm oven. If free fat was deposited on the large surface area of finely divided nibs, it was however felt to be inadvisable to blow air at 60°C through a bed of broken beans for up to 4 hours in order to complete the drying process.

From that observation the treatment of example 6(f) was devised which appears to have given the best flavour quality from the present series of trials (see example 8 and Table 3 - below) .

Example 6(f)

Broken beans were dried by blowing air at ambient temperature for 24 to 26 hours over the debris spread thinly on trays. The partially dried nibs, a few were still rubbery and therefore not completely dry, were stored and made into liquors without any further treatment to fully dry the nibs. Liquors made from nibs dried at ambient temperature throughout have shown the lowest levels of "wheaty" or "rancid" flavour and may indeed be completely free from that flavour defect . Furthermore, the nibs did not develop any fat bloom while stored for three days at tropical temperatures in Malaysia.

Example 6 (g) Recommended process On the basis of the observations from the above examples 6(a) to 6(f) , the following preferred process was devised using standard fermented beans after 6 days box fermentation.

The beans were washed for 10 minutes to remove residual mucilage and then skin-dried, keeping the external temperature of the skin dried beans below 45°C. The skin dried beans were broken either manually or mechanically between rollers. The broken beans were then spread on trays and dried for about 24 hours in a current of air at ambient temperature blown over but not through the debris. After 20 hours drying the nib moisture was less than 7.5%. A dark purple brown colour in the dried nibs was achieved which produced a dark and viscous liquor with distinct cocoa flavour and low astringency and acidity. Particles of dry shells that were free of adhering nibs were removed by coarse winnowing or sieving.

Results of taste trials

Example 7 : Tests of different genotypes

BAL209, PBC123, NA33 and UIT1 each with 0 and 10 days post harvest pod storage and prepared by (1) fast drying whole beans and (2) broken beans according to example 6(c) were tested. Fifty kilograms of wet beans were fermented in baskets according to BAL/BCCA flavour trial procedure.

The results are the averages of 2 tests of each liquor from a first set in which the four genotypes with the same drying treatment were tested and from a second set of 4 comprising a single genotype with the 2 pod storage treatments and the 2 drying conditions. Sun dried samples of whole beans of all four genotypes are available.

Results in Tables 2 and 3 show that slow drying of broken beans has consistently improved the flavour and is more effective in increasing cocoa flavour and reducing astringency than the post harvest pod storage treatment . Improvements were particularly pronounced when the new drying procedure was applied to BAL209 and UITl both without pod storage. This suggests that the drying treatment is affecting the polyphenol composition.

When polyphenol concentration and astringency are high, as in BAL209 and UITl, a great proportion of the critical material is altered and the effect is then more dramatic. In addition to increasing cocoa flavour intensity and reducing astringency, the new drying process tends to retain the characteristic secondary flavours of the genotypes, e.g. the brown fruit/floral notes of PBC123 and NA33 and the bitterness of UITl.

TABLE 2

Table 2 Effects of drying treatments applied to genotypes with 0 and 10 days pod storage

BAL209 A33 lavour characteristic 0-HA O-NP 10-HA 10-NP O-HA O-NP 10-HA 10-NP

Cocoa flavour 1.9 5.9 4.7 6.4 5.1 7 6.1 7.7 intensity

Acid/ sharp 3.6 1.3 2.6 1.4 2.6 1.4 2.2 1

Astringent 5.9 1.6 3.9 1.6 2.5 1.4 2.1 1.4

Bitter 4.9 1.1 3.1 1.3 2.3 1.1 2.1 0.9

Fragrant floral 0 0 3.1 1.4 0 0 1.4 1.2

Brown fruit 0 0 09 0 1 2.7 2.9 2.1

Viscous/ thick 5.3 7 6.2 7.2 6.6 8 6.9 8 mouthfeel

PBC123 UITl

Cocoa flavour 6 6.9 6.3 7.5 2.3 4.7 2.2 4.5 intensity

Acid/sharp 2.2 1.1 2.6 0.9 2.9 1.5 2.5 1.1

Astringent 2.1 1 2.5 1 5.2 2.5 4.9 2.4

Bitter 1.6 1.2 2.2 0.9 4.6 2.1 4 1.8

Fragrant floral 0 0 0 0 0 0 0 0

Brown fruit 2.8 1.9 2.6 1.8 0.5 0 0 0

Viscous/thick 7.1 7.6 7 7.8 5.2 6.6 5.3 6.4 mouthfeel

Key to table :

Genotypes, BAL209, NA33, PBC123 and UITl.

O-HA = 0 Days pod storage and hot air dried.

10-NP = 10 Days pod storage and new drying process [example 6(c)]

10-HA = 10 Days pod storage and hot air dried.

10-NP = 10 Days pod storage and new drying process [example 6(c)] . Characteristics were scored for intensity on 10cm. open line scales. Higher scores denote stronger intensities. Scores are the averages of 2 blind tests of each liquor. Differences greater than 1.0 are significant.

TABLE 3

Table 3 Effects of pod storage and drying treatments on flavour characteristics averaged over all four genotypes N - 16 for each treatment.

Cocoa flavour Acid/sharp Astringent Viscous/thick intensity mouthfeel

0 Days pod storage 5 2.1 2.8 67

10 Days pod storage 57 1.8 2.5 6.9

Hot air drying 4.3 27 3.6 6.2

New drying process 6.3 12 1.6 7.3 6(c)

The new drying process is more effective than pod storage in bringing about the desired changes in these four critical flavour characteristics.

Example 8: Beans from mixed planting materials BAL standard process versus new process

Twenty five kg samples were taken on eight successive days just before the fermented beans were due to go on to the hot bed dryers. 2 kg coned and quartered samples in net bags were dried together with 2.5 tonne lots of fermented beans from which the 25 kg samples had been taken. The remainder of the 25 kg sample was washed, skin dried and broken manually. The broken beans were dried according to the above drying treatments in example 6(c) (4 samples) , example 6(d) (3 samples) and example 6(f) (1 sample) . The results in Table 4 show that the new drying process improved the flavour on all eight occasions. The drying treatment of example 6 (d) was better than the treatment of example 6(c) and the best overall treatment was example 6(f) in terms of increased cocoa flavour and reduced astringency combined with a lower score for "wheaty/rancid" flavour than in any of the other drying treatments of broken beans from the examples.

TABLE 4

Table 4. Effects of drying treatments

Air at Treatment Treatment Treatment Target

60° 6(c)# 6(d)# 6(f># flavour

* $

Cocoa flavour intensity 1.7 4.6 6.1 6.6 7.1

Ac d/sharp 5.4 2.5 1.5 1.5 1.3

Astringent 5.2 3.5 1.9 1.7 1.7

Bitter 4.4 2.8 1.6 1.1 1.1

Fragrant/floral 0 0 0.6 0.6 1.3

Viscous/thick mouthfeel 4.9 6.4 6.8 7 7.6

Wheaty/rancid Absent Present Present Uk/Absent k/absent

Number of samples 8 4 3 1 1

Total number of tastings 10 7 9 2 3

Key to table:

* = BAL standard beans, whole hot air dried. 8

Samples tested. 6(c)# = Drying treatment in example 6(c) . Broken beans dried in current of air for 16 hours then for

4 hours at 60°C. 6(d)# = Drying treatment in example 6(d) . Broken beans. Slower ambient air drying for 20-24 hours followed by hot air drying for 4 hours .

6(f)# = Drying treatment in example 6(e) . Broken beans. Slower ambient air drying for 24-26 hours. No further treatmen .

$ = Target flavour from earlier experiments (results not shown) .

Claims

1. A method of processing beans of the cocoa plant Theobroma cacao, the method comprising at least partially deshelling, and subsequently drying the beans.

2. A method as. claimed in claim 1, in which the beans are at least partially deshelled prior to the drying step.

3. A method as claimed in claim 1 or claim 2, in which the beans are dried at a temperature an ambient temperature of from 15°C to 35°C, followed by air heated to a temperature of from 45°C to 75°C.

4. A method as claimed in claim 4, in which the ambient temperature is from 20°C to 30°C.

5. A method as claimed in claim 3 or claim 4, in which the heated air is from 50°C to 65°C

6. A method as claimed in claim 1 or claim 2, in which the beans are dried at a temperature an ambient temperature of 25°C, followed by air heated to a temperature of 60°C.

7. A method as claimed in claim 1 or claim 2, in which the beans are dried at an ambient temperature alone of from 15°C to 35°C.

8. A method as claimed in claim 7, in which the ambient temperature is of from 20°C to 30°C.

9. A method as claimed in claim 8, in which the ambient temperature is 25°C.

10. A method as claimed in any one of claims 1 to 9, in which the method additionally comprises a skin drying step prior to the deshelling step and the subsequent drying of the beans.

11. A method as claimed in any one of claims 1 to 9, in which the method additionally comprises a primary washing step prior to the deshelling step and the subsequent drying of the beans.

12. A method of reducing levels of acidity in fermented beans of the cocoa plant Theobroma cacao to improve cocoa flavour, the method comprising at least partially deshelling the beans to the air, prior to drying the beans, such that the organic acid level in the beans is reduced.

13. A method as claimed in claim 12, in which the the beans are at least partially deshelled prior to the drying step.

14. A method as claimed in claim 12 or claim 13, in which the beans are dried according to any one of claims 3 to 9.

15. A method as claimed in any one of claims 12 to 14, in which the improved flavour has a greater level of cocoa flavour but a reduced level of acidity, bitterness and astringency flavours.