Method for Producing a Pumpable Paste from the Seeds of Nut or Stone Fruits

Abstract

A method for preparing a pumpable batch composition of stone fruit and/or nut fruit seeds, in particular nuts, almonds or nut and almond mixtures, with the following steps: Breaking open of the already pitted or stoned stone-fruit or nut-fruit seeds first takes place by pre-crushing. A hot air and/or vacuum exposure of the composition arising from the pre-crushing then takes place for the purpose of breaking open its cells. This is followed by a usually single-stage, optionally also multi-stage, further grinding of the composition arising from the pre-crushing and the hot air or vacuum exposure to form a pumpable batch composition.

Claims

1. A method for preparing a pumpable batch composition of stone fruit and/or nut fruit seeds, in particular nuts, almonds or nut and almond mixtures, with the following steps: Breaking open of the already pitted or stoned stone-fruit or nut-fruit seeds first takes place by pre-crushing; A hot air and/or vacuum exposure of the composition arising from the pre-crushing then takes place for the purpose of breaking open its cells; and at least a single-stage grinding of the composition arising from the pre-crushing and the hot air or vacuum exposure to form a pumpable batch composition.

2. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein the pre-crushing is pre-grinding, which preferably brings about a pre-grinding material, which essentially or at least predominantly has an average particle size in the range from 4/100 mm to 30/100 mm.

3. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein the hot air or vacuum exposure is in particular controlled via the exposure time, in such a way that the residual moisture is reduced to less than 2.1% and preferably to less than 1.85%, ideally to 0.5% +/−0.2%.

4. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein the air temperature of the hot air used for the drying lies in the region of over 60° and ideally in the region of over 75°.

5. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein the air temperature of the hot air used for the drying lies in the region of less than 100° and ideally in the region of less than 90°.

6. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein the hot air used for the drying flows through the drying area in such a way that it is conducted away from there still while the drying process continues to progress, as soon as it has absorbed a certain quantity of moisture according to measurement or experience.

7. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein for the drying a vacuum with an absolute pressure of less than 0.25 bar and preferably in the region of 0.1 bar is applied.

8. The method for preparing a pumpable composition of stone fruit or nut fruit seeds, in particular nuts and almonds according to claim 1, wherein no water, oil or other substance foreign to stone fruit or nut fruit seeds is added during the pre-grinding and as a rule also during the further grinding and as a rule also during the further grinding.

9. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein the application of hot air or vacuum takes place in a horizontal drum mixer, which keeps the stone fruit or nut fruit seeds undergoing pre-crushing in permanent motion.

10. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein the pre-crushing preferably takes place by a pre-crushing device, which includes a crushing cone rotating with a—preferably vertically arranged—shaft, which rotates in a stationary crushing ring thereby forming a crushing gap, wherein the surfaces forming the crushing gap between them are typically provided with a driver-forming profiling for the entry of the stone fruit or nut fruit seeds to be pre-ground into the crushing gap.

11. The method for preparing a pumpable composition of stone fruit or nut fruit seeds according to claim 1, wherein the application of hot air or vacuum is carried out in a conching device with a conching container at least essentially closed and a usually multi-arm conching tool preferably rotating therein on a horizontal shaft.

12. The method for preparing a pumpable composition of stone fruit or nut fruit seeds, in particular nuts or almonds according to claim 1, wherein the fine grinding takes place with the aid of an agitator bead mill, which preferably produces a final grinding material, which in solid phase has essentially or at least predominantly an average particle size in the range from 15/1000 mm to 10/1000 mm.

13. A device for carrying out the method of preparing a pumpable batch composition of stone fruit and/or nut fruit seeds, in particular nuts, almonds or nut and almond mixtures, with the following steps: Breaking open of the already pitted or stoned stone-fruit or nut-fruit seeds first takes place by pre-crushing; A hot air and/or vacuum exposure of the composition arising from the pre-crushing then takes place for the purpose of breaking open its cells; and Next at least a single-stage grinding of the composition arising from the pre-crushing and the hot air or vacuum exposure to form a pumpable batch composition; and wherein the device comprises a pre-crusher, a hot air or vacuum applicator and a fine grinding device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 shows a plant according to the invention for smaller quantities, in which only one horizontal mixer is used in which the vacuum is applied.

[0035] FIG. 2 shows a cross-section through a grinder which can be used for this example of embodiment for the purpose of the pre-crushing.

[0036] FIG. 3 shows a plant according to the invention for larger quantities. It is characterised by two horizontal mixers operating in parallel, a vacuum being applied in both.

DETAILED DESCRIPTION

[0037] FIG. 1 shows a first example of embodiment of the invention, here using the example of hazel and/or cashew nuts and almonds. However, the description also applies accordingly to other nut seeds or stone fruit seeds.

[0038] The said nuts or almonds are delivered whole or sliced via a conveyor 1, usually a screw conveyor or a vibration conveyor, onto pre-crusher 2. A device can be used as a pre-crusher 2 such as is marketed for example by the company Netzsch under the name Mastercream®.

[0039] This pre-crusher is ideally constituted as a conical grinder 3, for example such as that shown in FIG. 2. Conical grinder 3 is fed in the vertical direction from above. The nuts and almonds to undergo pre-crushing fall on crushing core 4 tapering upwards. Crushing core 4 has a preferably helical profiling. This helical profiling catches hold of the incoming nuts and pulls them into crushing gap 5. This crushing gap is formed by crushing cone 4 together with stationary crushing ring 6, in which it rotates. The rotation takes place together with a vertical shaft. In this way, the nuts, or almonds to undergo pre-crushing are smashed to pieces in the crushing gap. From there they fall into the second part of the grinder. This second part is formed by a cylindrical grinding disc 7 adjoining the lower edge of the grinding core. Cylindrical grinding disc 7 also has a profiling which assists the grinding.

[0040] The grinding process is typically carried out in such a way that the temperature of the nuts or almonds to be pre-crushed remains below 110°, throughout the entire pre-crushing process. This prevents an influence on the flavour or even the formation of toasted aromas. In most cases, water cooling of the pre-crusher and its grinder can be dispensed with, instead of which a suitable adjustment of the gap width of the grinder and/or its shaft speed is reached, such that excessive heating does not takes place.

[0041] Pre-crusher 2 is preferably operated with a shaft speed of approximately 3000 to 4200 revs/min. Crushing cone 4 rotates with a correspondingly speed.

[0042] A viscous composition of nut or almond paste arises in the pre-crusher. The particles contained therein for the most part have an average particle diameter in the range from 30/100 mm to approximately 4/100 mm.

[0043] Although a part of the oils and fats stored in the cells has already been mobilised in this composition, the composition is not pumpable. If the clear diameter of the connecting line is not selected too small and the connecting line is implemented short, the finished pre-crushed composition can fall downwards into the horizontal mixer arranged below under the effect of gravity without further aids.

[0044] A conching device 8 is ideally used as a horizontal mixer, such as is known from chocolate production.

[0045] Such a conching device 8 can be designed similarly, for example, to the conching device described by the applicant in its German patent DE 10 2017 001 784 B4. It is thus made the subject-matter of the present description by way of reference.

[0046] A conching device is characterised by a conching container 9. A horizontal shaft rotates in the latter. A multi-arm conching tool 10 is usually attached to the shaft. Its arms plough up the doughy composition, which arises as a result of the pre-crushing, literally with each rotation. In this way, the composition is subjected very uniformly to the vacuum which is met in the conching container or the hot air, which is met there, which is applied in the conching device.

[0047] The conching container is typically connected to a vacuum pump. The vacuum pump partially evacuates the conching container. It thus places the latter under an under-pressure. This preferably takes place in such a way that less than 25% of the ambient pressure prevails in the conching container, ideally an under-pressure in the region of 0.1 bar, absolute, prevails.

[0048] The conching device works in the charge operation. It is fed by the pre-crusher until such time as it has reached its nominal loading. The pre-crushing process thus stops. The conching process device now begins to operate.

[0049] Precisely with the use of a vacuum, it has proved to be expedient if the conching device is preheated with hot water conveyed in separate channels and not therefore with the hot water coming into contact with the product to be conched. The preferred water temperature lies in the region of 60°+/−15° C., still better in a region of 90°+/−10° C. A conching container time of 60 to 120 minutes is typically selected. The conching tools preferably rotate with speeds of less than 20 revolutions/min.

[0050] After the passage of this time, a residual moisture of the conched material with a correct adjustment of the pre-crushing and conching parameters should be set in the range from 0.5%, +/−20%.

[0051] As a result of such conching or mixing under the influence of a vacuum, the cell walls of the composition removed from the pre-crusher, which until now are still intact, are broken open. In this way, fats and oils previously still stored in the cells and therefore held immobile are released. At the same time, the residual moisture is reduced. The latter, because the cell water is also mobilised. This then however transfers directly into the gas phase, unlike the mobilised oils and fats.

[0052] The viscosity of the composition thus diminishes markedly. The previously doughy-viscous composition becomes markedly more fluid. Its pumpability correspondingly increases. According to the inventor's findings, it is not the vacuum alone that is responsible for this effect. On the contrary, the combination of a vacuum and the permanent longer-lasting (usually more than 45 min) agitation of the composition by the mixer or the conching device appears to account for the decisive effect.

[0053] After the conching has completed, a composition is present which is already so flowable that it can be pumped into a storage container with the aid of a thick matter pump. Piston pumps are certainly possible here, but far from the ideal means of choice. The use of an eccentric screw pump has proved to be ideal, for example the Nemo series from the firm Netzsch. In any case, on account of its now improved pumpability, the composition that has arisen through the mixing or conching under vacuum and possible moderate thermal heat application can be pumped through an agitator bead mill 11.

[0054] Ideally, use is made of an agitator bead mill of the type Masterrefiner®, such as is marketed by the firm Netzsch. Grinding balls with a diameter in the range between 2 mm and 8 mm have proved to be most suitable—with this or other agitator bead mills. The dwell time of the composition in the agitator bead mill reasonably lies in the range from 2 to 4 hours, the agitator bead mill usually being passed through repeatedly.

[0055] In this way, a product, i.e. a batch composition, can be achieved in the agitator bead mill, the average particle size of which predominantly lies in the range between 1.5/100 mm and 10/100 mm. The last remains of previously still stored fats and oils are thus mobilised. A readily pumpable batch composition thus arises. Its viscosity which can be measured with the rotary viscosimeter preferably lies (and without the addition of foreign matter) in the range from 1.00E+2 cP to 1.00E+4 cP. Such a batch composition can readily be further processed with the standard metering pump in the food industry and precisely metered to the end product.

[0056] It should be stated at this point that aforementioned-storage container 12 is not absolutely necessary. It is however advantageous. This is because it enables agitator bead mill 11 to operate for a longer period than just for the short period in which the next charge is unloaded from conching device 8.

[0057] For larger through-put quantities, the previously described method is modified such that two or more horizontal mixers or conching devices 8 are operated in parallel. In this way, it can be ensured by using a correspondingly large storage container 12 that the device for fine grinding, i.e. the agitator bead mill 11 or the Masterrefiner, can be continuously loaded. This is because one of the two horizontal mixers or one of the two conching devices can always be loaded alternately, whilst the other works in parallel so that further product can be made available in a short time, which can be fed to the agitator bead mill.

[0058] A further example of embodiment is largely constructed precisely the same as the previously described examples of embodiment.

[0059] It differs from the latter, however, in that no vacuum is applied in the conching device. Instead, its conching container is supplied with hot air. The hot air has a sub-Maillard temperature ideally around 90° C. It comes directly into contact with the composition. It thus not only serves for the indirect heating of the conching container.

[0060] The dwell time in the conching container is in this case somewhat higher than in the vacuum application. It then amounts in many cases to approximately 90 to 180 minutes.