DK201770469A1 - A method for drying fermented cocoa beans - Google Patents

Abstract

Described herein is a method for drying fermented cocoa beans, comprising the step of subjecting the fermented cocoa beans to a vacuum drying at a pressure of 200 mbar or below during at least a part of a drying process to obtain an average moisture content of 10% by weight or less. The method provides for an improved quality of the cocoa beans as the amount of volatile organic acids are reduced during the vacuum drying.

Description

<¹θ> DANMARK <¹°> DK 2017 70469 A1

<¹²> PATENTANSØGNING

Patent- og

Varemærkestyrelsen (51)

Int.CI.: A 23 G 1/02 (2006.01)

A23B 7/02(2006.01)

F 26 B 5/04(2006.01) (21) Ansøgningsnummer: PA 2017 70469 (22) Indleveringsdato: 2017-06-16 (24) Løbedag: 2017-06-16 (41) Aim. tilgængelig: 2018-03-19 (71) Ansøger: SPX FLOW TECHNOLOGY COPENHAGEN A/S, Østmarken 7, 2860 Søborg, Danmark (72) Opfinder: Peter Wagner, Rødhalsvej 8, 2970 Hørsholm, Danmark

Kim Bo Jensen, Smakkegårdsvej 179 st. tv., 2820 Gentofte, Danmark (74) Fuldmægtig: NORDIC PATENT SERVICE A/S, Bredgade 30,1260 København K, Danmark (54) Benævnelse: A method for drying fermented cocoa beans (56) Fremdragne publikationer:

EP 2005835 A1 US 5888562 A EP 1728434 A1 WO 2014127130 A1 EP 1308094 A2 (57) Sammendrag:

Described herein is a method for drying fermented cocoa beans, comprising the step of subjecting the fermented cocoa beans to a vacuum drying at a pressure of 200 mbar or below during at least a part of a drying process to obtain an average moisture content of 10% by weight or less. The method provides for an improved quality of the cocoa beans as the amount of volatile organic acids are reduced during the vacuum drying.

DK 2017 70469 A1

DK 2017 70469 A1 i

METHOD OF DRYING FERMENTED COCOA BEANS

TECHNICAL FIELD

The present invention relates to a method for drying fermented cocoa beans . In the cocoa bean production drying of the cocoa beans are important for the quality of the cocoa and the present invention suggest a method for improving the quality by modifying the traditional drying method.

BACKGROUND

In the cocoa production process the fermentation and drying of the cocoa beans is important for the quality of the cocoa and has significant impact on the quality of final chocolate for which it is used.

Since the fermentation and drying should happen relatively shortly after the beans has been harvested, it is often done by the farmer or at facilities near the farmers. In areas with wet season in the harvesting period conventional driers like e.g. fixed bed driers are used. This speeds up the drying time however it also has negative effect on the quality of the cocoa especially when using an air temperature higher than 60°C. Countries where there are areas with need for mechanical drying are Brazil, Ecuador, south east Asia and Cameroon .

Sometimes the fermented cocoa beans are dried initially traditionally using sun drying and then mechanically dried in the last stage to reach a low moisture. This reduces the risk of mould development, but it typically also gives a product

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DK 2017 70469 A1 with higher level of acetic acid and other organic acids, which again gives a lower quality product.

Organic acids in the final product provide an off-flavour which generally is found unpleasant by many consumers. The object of the present invention is to improve the quality of the final product by reducing the off-flavour emanating from the organic acids.

SUMMARY

In an aspect of the present invention, it is an object to provide a method for drying fermented cocoa beans, comprising the step of subjecting the fermented cocoa beans to a vacuum drying at a pressure of 200 mbar or below during at least a part of a drying process to obtain an average moisture content of 10% by weight or less.

The method of the invention provides for a way to remove the moisture as well as the volatile organic acids with low risk of the product being infected by molds. This ensures a higher quality as the volatile organic acids otherwise would have provided an off-taste in the final product. Furthermore, the most important organic acids, such as acidic acid may be removed efficiently without heating the cocoa beans to temperatures potentially decomposing or evaporating the valued components of the cocoa bean.

After harvest of the cocoa beans, the beans usually are fermented directly. Alternatively, the cocoa beans may be frozen or otherwise conserved, for later fermentation. The fermentation process begins with the growth of microorganisms. The microorganisms convert the pulp

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DK 2017 70469 A1 surrounding the beans to ethanol. Subsequently the ethanol is oxidized to acetic acid and then partly to carbon dioxide and water. Also, lactic acid and other organic acids are produced from ethanol and other alcohols. The organic acids play an important role in breaking down the pulp and the maturation of the cocoa bean by breaking down the cell walls. However generally, the organic acids are not wanted in the final cocoa product. The present invention provides a method of reducing the concentration of organic acids to an acceptable low level. As an example, experiments have shown that the level of acetic acids can be reduced to 0.10 to 0.12 g/kg.

According to an embodiment of the invention, the cocoa beans are harvested later than conventionally. The subject of the fermented cocoa beans to a vacuum drying allows for a late harvest point as the low pressure treatment almost immediately stops the fermentation. A late harvest point ensures maximum flavor development and thus a final product with increased quality .

It is generally recognized that the surface temperature of the cocoa beans should not exceed 60°C to avoid deterioration of valuable components of the cocoa beans. 60°C corresponds to the evaporation temperature for water at around 200 mbar. Thus, according to the present invention, the use of a pressure of 200 mbar or below ensures a high quality of the cocoa beans. To obtain a faster drying of the surface layers of the cocoa bean it is generally preferred to use a pressure lower than 200 mbar, such as 100 mbar or below, 50 mbar or below, 40 mbar or below, 30 mbar or below, 20 mbar or below. A fast drying of the surface layers provides for a reduced

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DK 2017 70469 A1 risk of mold formation. As the economy of the process becomes better with higher pressures, it is generally not desired to use a drying pressure lower than necessary. Thus, to obtain a satisfactory process economy it is generally not desirable to use a pressure of 0.1 mbar or lower, such as 0.3 mbar or lower. At present, it is believed that the optimal drying pressure balancing the drying rate and the process economy is between 0.5 mbar to 30 mbar, such as between 1 mbar to 20 mbar .

In some instances, it may be necessary or desirable to stop the fermentation before the maximum flavor development. For early harvested cocoa beans the fermented beans may subjected to a pre-drying step at ambient pressure and using sun light, whereby the fermentation on the outside of the cocoa beans is slowed down, whereas the fermentation in the interior of the beans is allowed to proceed. The pre-drying step reduces the risk of mold formation and at the same time allows for an acceptable quality of the cocoa beans.

In a certain embodiment of the present invention, the fermented cocoa beans being vacuum dried is heated in two or more temperature zones. In the beginning of the vacuum drying process the cocoa beans have a higher moisture content in the surface layers, which allows for a higher temperature in a first zone due to the cooling effect of the moisture being evaporated. As that drying process proceeds the cooling effect of the evaporating moisture decreases and it is desirable to use a lower temperature in a second or further temperature zone to reduce the risk of heat damaging the cocoa beans.

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According to a preferred embodiment of the invention, the final temperature zone has a temperature at 60°C or below to prevent deterioration or evaporation of valuable flavor components in the cocoa beans. Generally, the first temperature zone has a temperature 110°C or above to provide for a quick drying of the exterior layers of the cocoa bean.

In a certain embodiment, a mechanical drying step may be performed between the pre-drying step and the vacuum drying step. The mechanical drying may involve a fixed bed dryer, which is widely available close to the harvest points. The mechanical drying therefore allows the cocoa beans to be dried to a sufficient level and then shipped to a destination where a vacuum drying facility is located. The vacuum drying according to the present invention provides in this situation primarily for the removal of the organic acids and to a lesser extent to the evaporation of water in the cocoa beans. Thus, in a certain aspect of the invention the vacuum drying is at least performed when the moisture content is 10% by weight or below, such as 15% by weight or below, and suitably 20% by weight or below.

Whereas drying of the cocoa beans to a moist content of 10% by weight or less may be sufficient to stabilize the cocoa beans, it is generally preferred to dry the product to a lower level to improve the long-term storability. Thus, according to a preferred embodiment of the invention, the drying process is continued until a moisture content of 9% by weight, 8% by weight, or 7.5% by weight or less is reached.

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The vacuum drying may be performed in any suitable equipment, such as vacuum belt drying plants, vacuum drying cabinets, or vacuum freeze belt drying plants. Suitable equipment is available from e&e Series, which is a part of SPX Flow Inc. In certain preferred aspects of the invention the vacuum drying equipment is provided with two more temperature zones .

DETAILED DESCRIPTION

The cocoa bean used for the preparation of chocolate, is the fermented and dried seed of the cacao tree, Theobroma cacao. Cacao trees grow in a limited geographical zone of about 20° to the north and south of the Equator.

A cocoa pod (fruit) has a rough, leathery rind about 2 to 3 cm thick filled with sweet, mucilaginous pulp enclosing 30 to 50 large seeds that are soft and a pale lavender to dark brownish purple colour. Due to heat build-up in the fermentation process, cacao beans lose most of the purplish hue and become mostly brown in colour, with an adhered skin which includes the dried remains of the fruity pulp. Cocoa harvest is not restricted to one period per year and a harvest typically occurs over several months. In fact, in many countries, cocoa can be harvested at any time of the year. The pods on a tree do not ripen together, thus, harvesting needs to be done periodically through the year.

The harvested pods are opened, typically with a machete, to expose the beans. The pulp and cocoa seeds are removed and the rind is discarded. The pulp and seeds are then piled in heaps, placed in bins, or laid out on grates for several days. During this time, the seeds and pulp undergo fermenting, also called sweating, where the thick pulp liquefies as it

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DK 2017 70469 A1 ferments. The fermented pulp trickles away, leaving cocoa seeds behind to be collected. Sweating is important for the quality of the beans, which originally have a strong, bitter taste .

The wet beans are generally fermented for four to seven days and may be mixed every two days. The fermented beans are traditionally dried by spreading them out over a large surface and constantly raking them. Finally, the beans are trodden and shuffled about, packed, and shipped to recipient countries. Top cocoa beans producing counties include Ivory Coast, Ghana, Indonesia, Nigeria, Camaroon, Brazil, and Ecuador. Nearly 70% of the world crop today is grown in West Africa .

Usually, consumer roasting nutrient the roasting process occurs closer to the final The time and temperature conditions during the process affect the flavour characteristics and profile of the final product.

To obtain a high quality cocoa there is a fine balance between fermentation and drying:

1. To get high flavoured cocoa it is important that the fermentation is completed, but not extended beyond this point to give over-fermented beans,

2. It is important that the volatile organic acids produced during the fermentation is removed or reduced during the drying to get low acid cocoa, and

3. It is essential that drying is quick enough to avoid development of moulds.

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The present invention offers a solution to all three requirements for a high quality cocoa to be obtained. The first requirement may be met by allowing the fermentation to complete to full maturation of the cocoa bean as the fermentation can be stopped almost immediately by the initiation of the vacuum drying. The second requirement is met by vacuum evaporation of the volatile organic acids, as the evaporation temperature decreases considerably at a pressure of 200 mbar or below. The third requirement is met as the vacuum drying initially occurs fast as the heating initially can be relatively high due to the high content of moisture in the exterior parts of the cocoa bean.

As used in the present description and claims the term volatile organic acids include formic acid, acetic acid, glycolic acid, oxalic acid, lactic acid, valeric acid, isovaleric acid, isobutyric acid, butyric acid, propionic acid, pyruvic acid, maleic acid, malonic acid, succinic acid, fumaric acid, malic acid and mixtures thereof.

The vacuum drying performed according to the present invention may be deployed in any suitable vacuum or freeze-drying equipment. According to a preferred embodiment, the equipment comprises e&e Series vacuum and freeze drying technology from SPX Flow Inc. The vacuum drying may be operated in a batch or a continuous mode. When a batch drying operation is intended vacuum drying cabinets may be used, such as e&e vacuum drying cabinets (VDC). VDCs can be equipped with heating plates as well as with heated jackets for forming different temperature zones and/or for optimizing the heat convection or het radiation .

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When operated in a continuous mode a vacuum belt drying plant may be used as the vacuum drying equipment. Vacuum belt drying plants are designed for the continuous charging of cocoa beans. After the drying process, the coca beans can be prepared for shipment by e.g. packaging in jute sacks. Vacuum belt drying can be regarded as one of the most economical and gentle drying methods. Due to the vacuum, very low water evaporation temperatures can be achieved.

If a drying pressure below 5-6 mbar is selected the moisture may form ice crystals in the cocoa beans and it is more convenient to use a freeze drying plant. Freeze drying is generally less economical when compared to vacuum drying plants, however, the freeze drying is regarded the most gentle and aroma-protective method. Furthermore, freeze drying may provide a more open structure during drying, which facilitates the drying process.

Energy for the evaporation may be supplied from beneath and/or above the belt or tray of the vacuum drying plant. When the energy is supplied from beneath a heating element is generally positioned below the belt or tray, alternatively the heating element is integrated into the belt or tray. The heating element may be heated by hot water, steam, or another suitable heating medium. When the energy is supply from above the belt or tray, radiation is generally used as a way of conveying energy to the cocoa beans to be dried. Radiation may be obtained from radiant heat panels or similar equipment. In a preferred aspect of the invention energy for the evaporation of moisture and volatile organic acids is supplied from

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DK 2017 70469 A1 beneath as well as above the belt or tray to obtain an efficient heat transfer and a fast treatment.

The cocoa beans may be treated in accordance with different temperature regiments. Usually, the heating element supplying heat from beneath the belt or tray does not provide a temperature high up on 60 to 70°C to prevent heat damage of the cocoa beans. The temperature may be higher at the start of the drying process e.g. such as 70°C, and lower towards the end of the drying process, e.g. 50 or 55°C. The heating from above the belt or tray may be higher, such as 150°C at the start of the drying process due to the high moisture content in the exterior layers of the cocoa beans, and lower towards the end of the process, e.g. 70 or 80°C, due to the low moisture content of the exterior layers of the cocoa bean. The different temperature regiments may easily be controlled by directing the cocoa beans to be dried through two more temperature zones in the vacuum drying apparatus.

In a certain embodiment of the present invention the cocoa beans are treated in four temperature zones. In a first temperature zone, the cocoa beans are dried by radiation from above at 150 °C, in a second zone the cocoa beans are treated at 120°C, in a third zone the cocoa beans are treated at 90°C and in a fourth zone the cocoa beans are treated at 60°C. The temperature of the heating element beneath the belt or tray is 60°C in the first two temperature zone and 55°C in the third and fourth temperature zones.

The various aspects and implementations has been described in conjunction with various embodiments herein. However, other

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DK 2017 70469 A1 variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality.

EXAMPLES

Fermented beans with a moisture content of 48.9% were obtained and dried at 1 mbar, 1.5 mbar and 30 mbar at varying times and temperatures.

The fermented beans dried at 1 mbar obtained a moisture content of 4.7% by weight after drying in 23 hours, keeping the cocoa bean surface temperature below 40°C at all times.

The fermented beans dried at 1.5 mbar obtained a moisture level of 5.7% after 8 hours and a moisture level of 5.2% by weigh after 10 hours. At all times the surface temperature of the cocoa beans was kept below 60°C.

The fermented beans dried at 30 mbar obtained a moisture level of 8.9 % by weight after 18 hours of drying. At all times the surface temperature of the cocoa beans was kept below 40°C.

For all drying tests the level of acetic acid was measured to be in the range of 0.10 to 0.12 g/kg, which is considered low and indicates that the product guality is good.

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Claims (10)

1. A method for drying fermented cocoa beans, comprising the step of subjecting the fermented cocoa beans to a vacuum drying at a pressure of 200 mbar or below during at least a part of a drying process to obtain an average moisture content of 10% by weight or less.

2. The method according to claim 1, wherein the cocoa beans are harvested later than conventionally.

3. The method according to claim 1 or 2, wherein the pressure in at least a part of the drying step is 50 mbar or below.

4. The method according to anyone of claims 1 to 3, wherein the fermented beans are subjected to a pre-drying step at ambient pressure and using sun light, whereby the fermentation on the outside of the cocoa beans is slowed down, whereas the fermentation in the interior of the beans is allowed to proceed.

5. The method according to anyone of the claims 1 to 4, wherein the fermented cocoa beans being dried is heated in two or more temperature zones.

6. The method according to anyone of the claims 1 to 5, wherein the final temperature zone has a temperature at 60°C or below.

7. The method according to any of the claims to 6, wherein the first temperature zone has a temperature 110°C or above.

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8. The method according to anyone of the claims 1 to 7, wherein the drying process is continued until a moisture content of 7.5% by weight or less is reached.

5

9. The method according to any of the claims 1 to 8, wherein a mechanical drying step is performed between the pre-drying step and the vacuum drying step.

10. The method according to claim 9, wherein the mechanical 10 drying is a fixed bed dryer.

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IMmsH Fäto? Asm Öma

SEARCH REPORT - PATENT Application No. PA 2017 70469 1. 1 1 Certain claims were found unsearchable (See Box No. I). 2. 1 1 Unity of invention is lacking prior to search (See Box No. II). A. CLASSIFICATION OF SUBJECT MATTER A23G 1/02 (2006.01); A 23 B 7/02 (2006.01); F 26 B 5/04(2006.01) According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED PCT-minimum documentation searched (classification system followed by classification symbols) IPC/CPC: A23B, A23G, F26B Documentation searched other than PCT-minimum documentation Electronic database consulted during the search (name of database and, where practicable, search terms used) EPODOC, WPI, FULL TEXT: ENGLISH CAPLUS, FSTA C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant for claim No. X EP 2005835 Al (KRAFT FOODS R&D INC) 2008.12.24 1-3,8 Paragraphs [0020]-[0026] X US 5888562 A (HANSEN CARL ERIK et al.) 1999.03.30 1-3,8 Example 6 X EP 1728434 Al (KRAFT FOODS R&D INC) 2006.12.06 1-3,8 Example 1 A WO 2014127130 Al (MARS INC) 2014.08.21 Paragraph [000116] 1,8 M Further documents are listed in the continuation of Box C. * Special categories of cited documents: P Document published prior to the filing date but later than the A Document defining the general state of the art which is not priority date claimed. considered to be of particular relevance. T Document not in conflict with the application but cited to D Document cited in the application. E Earlier application or patent but published on or after the filing date. understand the principle or theory underlying the invention. X Document of particular relevance; the claimed invention cannot be considered novel or cannot be considered to involve an inventive step when the document is taken alone. Y Document of particular relevance; the claimed invention cannot be considered to involve an inventive step when the document is combined with one or more other such documents, such L Document which may throw doubt on priority claim(s) or which is cited to establish the publication date of another citation or other special reason (as specified). O Document referring to an oral disclosure, use, exhibition or other means. combination being obvious to a person skilled in the art. Document member of the same patent family. Danish Patent and Trademark Office Date of completion of the search report Helgeshøj Allé 81 DK-2630 TaastruD 22 September 2017 Denmark Authorized officer Telephone No. +45 4350 8000 Facsimile No. +45 4350 8001 Peter Philip Hoick Telephone No. +45 4350 8558

Search Report

SEARCH REPORT - PATENT Application No. PA 2017 70469 C (Continuation). DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant for claim No. A EP 1308094 A2 (NESTLE SA) 2003.05.07 Example 1

Search Report

SEARCH REPORT - PATENT Application No. PA 2017 70469 Box No. I Observations where certain claims were found unsearchable

This search report has not been established in respect of certain claims for the following reasons: 1. I I Claims Nos.:

because they relate io subject matter not required to be searched, namely:

2. I I Claims Nos.:

because they relate to parts of the patent application that do not comply with the prescribed requirements to such an extent that no meaningful search can be carried out, specifically:

3. I I Claims Nos.: because of other matters.

Box No, II Observations where unity of invention is lacking prior to the search

The Danish Patent and Trademark Office found multiple inventions in this patent application, as follows:

Search Report

SEARCH REPORT - PATENT Application No. PA 2017 70469 SUPPLEMENTAL BOX Continuation of Box [.]

Search Report