Method for reducing germs in dried fruit containing oil and / or fat, and refining-grinding arrangement

Abstract

The invention relates to a method for reducing germs in dried fruit containing oil and / or fat, in particular cocoa beans, the dried fruit being subjected to at least one thermal treatment and an exposure to moisture in a housing arrangement (4). In a first step, the dried fruit is filled into a treatment housing part (14) of the housing arrangement (4) and the treatment housing part (14) is heated; in a second step, at least one refining process is started; in a third step, a predetermined maximum temperature TM ≤ 110°C is reached; in a fourth step, moisture in the form of water and / or steam is fed into the treatment housing part (14); and in a fifth step, a refined product is at least dried. The invention also relates to a refining-grinding arrangement for carrying out the method.

Description

[0001] Process for the germ reduction of oil- and / or fat-containing dried fruits and refining-grinding arrangement

[0002] The invention relates to a method for reducing germs in oil- and / or fat-containing dried fruits, in particular cocoa beans, wherein the dried fruits are subjected to at least one heat treatment and a moisture supply in a housing arrangement. Furthermore, the invention relates to a refining-grinding arrangement for carrying out such a method.

[0003] Dried fruits containing oil and / or fat require pretreatment. Cocoa beans, for example, are fermented and stored. This can lead to the dried fruits becoming contaminated with pathogens, with salmonella being the most hazardous contamination source for later consumption. For products that are to be roasted, such as cocoa beans, the roasting process serves to reduce germ contamination due to the heat exposure during the subsequent treatment of the dried fruits. However, it should be noted that overly intense heat treatment leads to off-flavors, which are undesirable during the processing of dried fruits. Processes using ionizing radiation or gamma radiation have also been developed to further reduce germ contamination. However, these processes require an additional treatment step and are therefore expensive and complex.

[0004] Furthermore, German patent application DE 34 17 125 A1 discloses a process for reducing germs. In this process, the dried fruit is treated to form a pourable and / or flowable mass by adding moisture and then abruptly increasing and decreasing the temperature and pressure, followed by homogenization under reduced pressure. However, this process also requires additional effort or fundamentally new equipment with conventional devices to achieve the maximum pressure and temperature values ​​and to provide the reduced pressure. Furthermore, the high heat input always carries the risk of a flavor change.

[0005] The present invention is therefore based on the object of avoiding the above-mentioned disadvantages in a simple and cost-effective manner.

[0006] This object is achieved by a method according to the invention in that, in a first step, the dried fruits are filled into a treatment housing part and the treatment housing part of the housing arrangement is heated; in a second step, at least one refining process is initiated; in a third step, a predetermined maximum temperature TM < 110°C is reached; in a fourth step, moisture in the form of water and / or steam is introduced into the treatment housing part; and in a fifth step, a refining product is at least dried. In connection with cocoa beans and the chocolate to be made from them, "refining" is understood to mean "conching," whereby the chocolate is constantly circulated and kneaded, again removing volatiles. The maximum temperature TM refers to the temperature in the treatment housing part.

[0007] A particularly gentle, effective method for reducing germs is achieved by preheating the treatment housing to approximately 90°C (DM). Adding moisture in the form of water at a rate of 2g / 100g (water / dried fruit) to a maximum of 5g / 100g at the beginning of the finishing process, with additional moisture being added at defined intervals, creates a humid atmosphere that significantly supports decontamination. The moisture addition can be monitored gravimetrically or volumetrically, for example. The humid atmosphere can also be monitored.

[0008] If air mass exchange, also known as open process control, is possible during the finishing process, adhesions can be permanently prevented, even in high humidity conditions. This air mass exchange can be controlled to facilitate easier monitoring of the humidity in the treatment housing. This can be achieved, for example, by opening and closing the treatment housing or by aspiration.

[0009] If an additional milling process is initiated in the second step alongside the finishing process, the processing can be made even more efficient, and germ reduction can be further improved. In particular, by conducting the milling process with the highest possible grinding pressure, a high level of germ reduction is achieved while producing the best possible flowable finished product.

[0010] The object is also achieved by a refining-grinding arrangement for carrying out such a method, wherein a housing arrangement with a drive device for a drive shaft and a control device are provided, which has a treatment drum in which several kneading wheels are provided which can be rotated via a drive shaft, wherein the kneading wheels are connected to the drive shaft via kneading arms, wherein a grinding arrangement is provided between the kneading wheels and the treatment drum, wherein a heating device is provided for the treatment drum, wherein a connection device for supplying moisture is provided and wherein the control device is designed to regulate at least the maximum temperature TM and the moisture supply for the purpose of germ reduction. By suitable control of such a refining-grinding arrangement, a very simple and efficient germ reduction during a refining-grinding process is possible.

[0011] In this case, it is particularly advantageous if the grinding arrangement is adjustable. The grinding arrangement can be constructed from grinding arms on the kneading wheels directed toward the treatment drum and from grinding rods provided on an inner side of the treatment drum, with the grinding arms being adjustable in terms of their angle of attack.

[0012] In a particularly advantageous manner, a measuring sensor for measuring humidity is provided in the treatment housing part.

[0013] The invention is explained in more detail with reference to a drawing, in which: Figure 1 shows a perspective sectional view of a finishing grinding arrangement according to the invention, and

[0014] Figure 2 shows a diagram of germ reduction depending on the temperature of a treatment drum and the time.

[0015] Figure 1 shows a perspective sectional view of a finishing-grinding assembly 2 according to the invention. In the present case, a chocolate product is to be produced, so that one can also speak of a conching process. The finishing-grinding assembly 2 comprises a housing assembly 4 with a schematically indicated drive device 6 for a drive shaft 8. Also schematically shown is a control device 10 which, as described later, influences the germ reduction of a conching product, in this case chocolate, by regulating certain process parameters.

[0016] In the refinement-grinding arrangement 2 shown, the cocoa beans are guided via hoppers 12 into a treatment housing section designed as a treatment drum 14 to undergo a conching and grinding process. For this purpose, several kneading wheels 16, of which only one is shown here, are provided in the treatment drum 14. These kneading wheels 16 are connected to the drive shaft 8 via kneading arms 18. The kneading wheels 16 and the associated kneading arms are responsible for the conching process. A grinding arrangement 22 is provided between the kneading wheels 16 and an inner surface 20 of the treatment drum 14. The grinding arrangement 22 essentially consists of grinding arms 24 on the kneading wheels 16 directed toward the treatment drum 14 and of grinding rods 26 provided on the inner side 20 of the treatment drum 14.The grinding arms 24 are provided with a support plate 28 at their free end, so that a grinding pressure can be adjusted via an angle of attack of the grinding arms 24 via a grinding pressure adjustment device 30.

[0017] For heating the treatment drum, a heating device 32 is provided, which is fluidly connected to a hot water jacket 34 of the treatment drum 14. Moisture can be supplied to the treatment drum 14 via a connection device 36. For further details on the basic structure of such a finishing-grinding arrangement, reference is made to GB 2 317 840 A.

[0018] In order to achieve the best possible germ reduction in the cocoa beans to be treated using the gentlest possible conching and grinding process in the refinement and grinding arrangement 2 described above, a preferred method for germ reduction in the cocoa beans is described below. In a first step, the treatment drum 14 of the housing arrangement 4 is preheated to a temperature of TM = 90°. After this temperature has been reached, the cocoa beans are introduced into the treatment drum 14 via the hoppers 12 in a second step. In a third step, the conching and grinding processes then begin, with moisture in the form of water, here 2 g / 100 g (water / dried fruit), being added in a fourth step at the beginning of the processes via the connection device 36. Further moisture is then added at further defined intervals.The humidity and temperature in the treatment drum 14 are controlled by the control device 10. All of this takes place in an open process, allowing for air mass changes during the conching and grinding process. The grinding process is carried out with the greatest possible pressure to ensure the flowability of the conching product, in this case, chocolate, and to prevent sticking or clumping of the chocolate.

[0019] Figure 2 shows a diagram illustrating the influence of jacket temperature on germ reduction, with 2 g of moisture being added per 100 g of water during an open system operation. The treatment drum was preheated to TM = 60 °C in a first test (38), to TM = 80 °C in a second test (40), and to TM = 90 °C in a third test (42). The product temperature in °C is shown on the right-hand Y-axis; this temperature is essentially below the temperature of treatment drum 14. The effects on germ reduction can be seen in curves 44, 46, and 48, with curve 44 corresponding to a treatment temperature of 60 °C, curve 46 to a treatment temperature of 80 °C, and curve 48 to a treatment temperature of 90 °C. The strongest germ reduction, readable on the left Y-axis in logarithmic form (GKZ), was achieved at a temperature TM of the treatment drum 14 of 90 °C.

Claims

PATENT CLAIMS 1. A method for reducing the germ count of oil- and / or fat-containing dried fruits, in particular cocoa beans, wherein the dried fruits are subjected to at least one temperature treatment and one supply of moisture in a housing arrangement (4), characterized in that, in a first step, the dried fruits are filled into a treatment housing part (14) of the housing arrangement (4) and the treatment housing part (14) is heated, in a second step at least one refining process is started, in a third step a predetermined maximum temperature TM < 110°C is reached, in a fourth step moisture in the form of water and / or steam is introduced into the treatment housing part (14), and in a fifth step a refining product is at least dried.

2. A method for reducing germs in roasted oil- and / or fat-containing dried fruits according to claim 1, characterized in that the housing arrangement is preheated to approximately TM = 90°C.

3. A process for reducing germs in roasted oil- and / or fat-containing dried fruits according to claim 1 or 2, characterized in that at least at the beginning of the refining process, moisture in the form of water in a quantity of 2g / 100g [water / dried fruits], maximum 5g / 100g, is added, with further moisture being added at defined time intervals. A process for reducing germs in roasted oil- and / or fat-containing dried fruits according to one of the preceding claims, characterized in that an air mass change, also called an open process, is possible during the refining process. A process for reducing germs in unroasted oil- and / or fat-containing dried fruits according to one of the preceding claims, characterized in that, in addition to the refining process, an additional milling process is initiated in the second step. A process for reducing germs in roasted oil- and / or fat-containing dried fruits according to claim 5, characterized in that the milling process is carried out with the greatest possible milling pressure.A refining-grinding arrangement for carrying out a method according to one of claims 5 or 6, characterized in that a housing arrangement (4) with a drive device (6) for a drive shaft (8) and a control device (10) are provided, which has a treatment drum (14) as a treatment housing part, in which a plurality of kneading wheels rotatable via a drive shaft are provided, wherein the kneading wheels (16) are connected to the drive shaft (8) via kneading arms (18), wherein a grinding arrangement (22) is provided between the kneading wheels and the treatment drum (14), wherein a heating device (32) is provided for the treatment drum (14), wherein a connection device (36) for supplying moisture is provided, and wherein the control device (10) is designed to regulate at least the maximum temperature TM and the moisture supply for the purpose of germ reduction. The finishing and grinding arrangement according to claim 7, characterized in that the grinding arrangement (22) is adjustable. The finishing and grinding arrangement according to claim 8, characterized in that the grinding arrangement (22) is constructed from grinding arms (24) on the kneading wheels directed toward the treatment drum (14) and from grinding rods (26) provided on an inner side (20) of the treatment drum (14), wherein the grinding arms (24) are adjustable in terms of their angle of attack. The finishing and grinding arrangement according to one of claims 7-9, characterized in that a measuring sensor for measuring moisture is provided in the treatment housing part (14).

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