JPH07100138B2 - Method for removing the hull of bean seeds and apparatus for carrying out the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises bean-like seeds, in particular bean-like seeds, comprising the steps of heating the seeds to a predetermined temperature inside the shell grains and exposing the seeds to mechanical stress to separate the husks. A method for removing soybean hulls.

Such a method is proposed in FA-A-1580933, for example. In this context, legume seeds, especially soybeans, have some ingredients that must be first driven out or destroyed as they are not suitable for nutritional use. In the case of soybeans, it is a problem with some enzymes, especially antitrypsin or poxidase, but the process of dehulling bean-like seeds such as cocoa beans expels or destroys these inappropriate substances. It is not necessary to combine it with the processing for Soybeans as food for humans are almost always cooked, which destroys harmful enzymes. In the case of cocoa beans, it may be treated with a flavor modifying additive. Therefore, it has heretofore been proposed to carry out a heat treatment to remove the hull of the bean seed so that only the surface of the bean is heated sufficiently to loosen the hull from the kernel. For example, such a proposal is DE-C-
2354617, EP-C-52218 and the like.
Also in these cases a hot gas stream was used. Although the amount of energy is smaller than warming the beans, warming the bean surface, but in all cases there is considerable energy consumption. In addition, it is necessary to premoisten the seeds, as can be derived from the last-mentioned specification. This, of course, comes at the expense of additional equipment and work.

From FR-A-1388511 it is also known in the case of cocoa beans to heat the beans by a high frequency field and to further expose the beans to a hot gas stream before or at the same time. This specification very clearly shows the effect of such treatment. That is, it is the water content that is in any case present in the seed kernels that is used to blow off the hulls, which results in fine hairline cracks in the kernels through which Evaporated water comes out from the outside. As is known, such treatments are often not suitable for cocoa beans. This is because, in this very delicate product, it is a matter of flavor tint that is only adjusted by the process of producing the various flavors. For example, bitter chocolate can never be made that way. However, the conditions for soybean (or similar bean seed) are still other conditions. In the case of such seeds, it is just as effective if the water vaporizes from the inside of the grain, thereby exerting an enzymatic destructive effect. Indeed, it must be acknowledged that the known method according to French Patent 1,388,511 is relatively expensive. First, a large amount of energy is required to heat by the flow of gas. And also, the placement of the radio frequency field is expensive not only for the equipment, but also for the energy (especially less efficient when creating the radio frequency field not only in the beans but in the fluidized bed that has to be heated). . Furthermore, when large amounts are processed, the equipment required will be a crude operation that will result in failure.

The above representative aspects of the prior art show that, despite numerous attempts, the problem has not been solved satisfactorily. The object of the present invention is therefore to modify the method of the type mentioned at the outset so that the water content of the grain is used to remove the hull, but this can be achieved in a cost-saving manner. .

In order to achieve this object according to the invention in a surprisingly advantageous manner, the heating step is carried out as follows: a continuous, dense flow of seeds is gradually guided through an elongated closed passage, where the passage is hot. This is done by contacting the surface with preheating to the inside of the kernels and then exposing or exposing the seeds to a stream of hot gas to heat or maintain it at a predetermined temperature, which in turn leads to mechanical stress at the stage of separating the next hull. To be exposed to. In a sense, this is the reverse of the last-mentioned FR-A-method, whereby high-frequency fields are additionally avoided. By utilizing the contact heat by bringing the seed into contact with a hot surface, a direct heat transfer takes place, only the amount of heat being absorbed by the seed having to be supplied. Therefore, any heat loss that occurs in the known manner is largely avoided in the case of the present invention. Now, this shouldn't lead to the hypothesis that this can deviate from the main point and eventually eliminate hot gas treatment. In this context, when the seed comes into contact with a hot surface, the heat transfer must be considered to be the strongest for the areas on the surface of the seed. Therefore, as a final result, the temperature of the surface is even higher with respect to the inside of the grain. Therefore, when trying to heat the grain to the desired temperature only by contact heat, it is unavoidable that the temperature becomes higher on the outside, which leads to a high degree of drying of the rind, which makes such husks There is a risk of straightening. Moreover, this results in burning of the surface and undesired changes in flavor. In contrast, by using the two processing steps according to the invention, heating of the grain is achieved up to a predetermined temperature, which is easy in such a way that the undesired effects of flavor are safely avoided. You can choose to. Therefore, the final treatment is only carried out in the second stage by treatment in a stream of hot gas, where-depending on the quality and nature of the seed to be treated-it is included in the grain for the seed. Heat the seeds (preferably without supplying additional heat energy) to allow sufficient time for the vaporization of the accumulated water
It is advantageous to interpose time intervals that are only maintained. However, such time intervals in which the seeds are properly stored in isolated bins, cells or the like should not be too long. Because too long a time interval carries the risk of heat loss, and moreover the vaporization process itself usually requires only a relatively short time, this time interval is less than 20 minutes, in particular less than 15 minutes, for example 10 minutes. It is preferable to adjust to minutes.

Of course, it is possible to guide the seed substantially individually on the heated vibrating surface, so that the seed rolls on the vibrating surface. However, even higher efficiencies are achieved because the seeds are contacted with the hot surface or with the surface heated by said hot surface on substantially all surfaces. This can be done, for example, in a rotating drum that is partially filled with hot sand for circulating the seeds in all directions. However, this involves a subsequent separation step for separating the seed from the sand.
It is therefore even more convenient to guide a continuous, and in particular a dense stream of seeds through a hot surface forming a hollow, e.g. tubular structure, which surrounds the seeds in all directions. If the seed stream is dense, heat localization will occur within the interior of the tubular surface, which will heat the kernel with very low loss. In this context, when the term "tubular surface" is concerned, the term is understood to mean that the surface must have a circular cross section, as the tube can be made with any desired cross section. should not be done.

Of course, when the seeds are heated in a hollow or tubular hot surface, a constant temperature gradient is obtained, especially when large amounts of seeds have to be treated so that the seed flow has a relatively large cross section. It occurs from outside to inside over the bulk cross section of the seed. Such a temperature gradient can be avoided by a particularly advantageous modification, in which the seed is contacted by another hot surface within the hollow structure formed by said hot surface. To achieve this, for example,
A rod-shaped or flat heating tool may be projected into the interior, but the heated "float" is placed inside the hollow hot surface, thus being surrounded by the hollow hot surface. You can also The "float" can be retained in the seed stream by the substantially radially extending spokes. However, as will be explained later, the most convenient implementation has a casing or housing provided with a surface to be heated which traverses the interior of the casing in the manner of a seed dryer. Because, on the one hand, such a heated surface across the casing allows heat to be more easily distributed over the entire cross section, and on the other hand, the crossed surface is a reinforcement that allows a lighter construction. Since it acts as a part, a high stability of the device is guaranteed.

In the above, the importance of the two-step heat treatment has already been pointed out. The step of treating with contact heat must, on the one hand, contribute to the heating of the seeds as much as possible and, on the other hand, avoid unwanted effects on flavor. Therefore, at the end of the treatment with contact heat, the seeds are
If brought to at least about 60% of the temperature at which the end of the subsequent treatment must be reached, and at which the seed is preferably below 100%, in particular at least 7%.
It is advantageous if it is brought up to 0%.

For example, in contrast to the prior art, which requires shock-like surface heating, deep effects must be achieved with this method.
Such deep effects act on a method of removing unwanted enzymes, the more basic the enzyme is, the more vapor formed inside the grain will be for such removal. Will have time. On the other hand, too long treatment times are detrimental to the energy balance. It has now been found that the contact heat treatment step can be carried out for a maximum of 30 minutes, preferably 5 to 25 minutes, in particular 15 to 25 minutes, for example 20 minutes, in order to best fulfill all requirements. Was issued.

After the step of treating the seeds with contact heat, the operation of treating the seeds with a stream of hot gas is carried out according to a particularly advantageous modification within a period of not more than 2 minutes, preferably not more than 1 minute, in particular 30 to 50 seconds, for example The energetic benefit is readily seen in that it can be done in about 40 seconds, and thus within a small fraction of the rest of the known method.

An apparatus for carrying out the method comprises at least one first fluidized bed for treating seeds in a stream of hot gas,
It is expedient to start from the type which has, after said first fluidized bed, at least a dehulling device for exerting mechanical stress on the seeds. This corresponds to all equipment of the type provided for impact-like surface treatment, not to the prior art from which the method departs. However,
Such a device is preheated, upstream of the first fluidized bed, formed as an elongated closed passage for gradually guiding a continuous dense flow of seeds, the passage having a heated surface. It has been found that the device can be easily adapted to the purpose of the method by interrupting the circuit. This preheating device has a closed casing structure for guiding the seeds, preferably under the influence of gravity, and thus a casing structure extending in a particularly vertical direction, the casing structure covering the surface to be heated. It is desirable to form so as to have. In this way, a device is obtained which substantially corresponds to the known heat treatment device for other purposes, so that no special construction is necessary. The device is therefore tunnel-shaped or well-pitted, of which the latter is preferred. This is because in this case the seed transfer can be realized under gravity, thus avoiding expensive transfer devices. The test showed another favorable effect. Surprisingly, movement through such vertical shafts involves mechanical friction on the surface of the seed, which additionally helps loosen the husk from the kernel, which is surprising. Found that about 50% of the rind was largely loosened at the exit of such devices.

This, of course, means that the casing structure has a heated surface therein, which preferably extends across the interior,
This applies in particular if the casing structure is designed in particular like a seed dryer. Not only does it cause a better distribution of heat on these surfaces, but it also provides frictional contact with the outer surface of the seed which will loosen the rind.

As already mentioned, in principle a rotating drum can be used to bring the seed into contact with the hot surface. Two different types of such devices are commonly used, one of which is formed by a drum roaster used, for example, for coffee and cocoa beans, the outer surface of which is heated by an open flame. These exposed flames present a risk of local overheating. In any case, it only removes the seed hulls and should not be baked. Other types of drums are used in the pasta industry to dry short products, in which the product to be dried is fed through caged tubes, usually over a casing surface formed by a screen. Blow air through. Therefore,
The problem of heat transfer by convection is more common than by applying contact heat. In other words, the energy consumption to achieve the deep effect will be considerable. For this reason, it is particularly advantageous if the preheating device comprises a jacket for circulating a fluid heat carrier (hot water or preferably steam) for indirectly heating the seed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The device for removing seed hulls can be designed in a manner similar to that described in German Patent 2,354,617 or European Patent 68,221 or 52,218, and it is believed that all modifications described in these documents can also be used.

Thus, for example, a first fluidized bed device 1 is provided,
This device is, for example, as proposed in European Patent 68,221, a chain with a protruding blade mount 3.
It is expedient to have a mechanical stiffening feeder to determine the exact dwell time of the conveyor 2 configuration. It would be advantageous if a more continuously rotating pulsator flap 4 was provided in the air passage of this first fluidized bed (alternatively, instead of locating the pulsator flap in the discharge passage as shown, the feed Can be placed in the aisle).
Such a pulsator flap 4 causes even better turbulence by periodically interrupting the flow of air, whereby the screen deck 5 of the first fluidized bed device 1 is simultaneously vibrated by the pulsating air flow. , Thus promoting fluidization. The first fluidized bed apparatus 1 has a rotary pocket lock 6 at its inlet. On the supply side of the air flow there is an air conditioner 8 located in a manner known per se behind the blower 7, which air conditioner 8 in particular passes the air passing through to a value of at least 120 ° C., preferably about 150 ° C.
Helps to heat up to ℃ or above. In known devices that only required shock-like heating of the seed surface,
Higher temperatures up to about 220 ° C have been proposed, but for the purposes of the present invention, the temperatures of the air are actually 130 ° C and 170 ° C.
It will be enough to keep it between. The reason will be explained later.

As is generally known, the air sucked by the blower 9 from the first fluidized bed 1 (hereinafter, the first is omitted and simply referred to as “fluidized bed 1”) is fed to the cyclone 10. This is because a large amount of skin particles are contained in and separated from the air stream supplied to the cyclone 10. The product of the cyclone 10 can in principle omit the blower 9 via the conduit 11, but in the case of the embodiment shown, a flap 12 is schematically provided, which, if desired, can discharge the exhaust air in the direction of the arrow 13. Only shown. However,
It has to be noted that the flap 12 can assume any desired intermediate position so as to expel only part of the air and circulate the other part. A similar flap 14 is provided in conduit 11 to adjust the desired location of fresh air added in the direction of arrow 15. The beans sent out from the fluidized bed 1 have already been partially peeled, and the peels of other portions are loosened from the grain,
In any case, it is fragile like a parchment. The beans are then carried by a conveyor 16 to stage 17, where the brittle husks are subjected to mechanical stresses, and the husks are peeled from the hot, elastic kernels. Stage 17 may be a first milling stage as proposed by European Patent 52,218, in which the beans are pre-milled to produce cracks or pointed parts of the beans. In this case, of course, the friable hull is shaved off, but because the elasticity of the grain is not used to loosen the rest of the hull which still adheres to the grains of the grain, such a process may result in residue of the hull being removed. To a greater extent, this effect is further favored by the fact that it is more difficult to separate the rind from the milled particles.

Therefore, it is desirable if the outer skin removing step 17 comprises at least one (two in the embodiment shown in FIG. 1) impact crusher 18. In this case, the beans are fed through the hopper into the area of the rotating pocket wheel 19, from which they are thrown outwards against a somewhat inclined impact wall 20. At this time, the remaining hull is stripped off, and in the case of soybean, the remaining hull is divided into two,
Then, the mixture of the hull and the grain is fed to each screw conveyor 22 through the respective shutes 21. It should be understood that the screw conveyors 16 and 22 are merely examples of transfer means, and of course any other transfer means may be applied if desired. In any case, the mixture of kernels and separated hulls is fed to the second fluidized bed 101 in this preferred embodiment, optionally via the transfer path 23, where the second fluidized bed 101 is probably fluidized. It is designed similar to bed 1, but omits mechanical aids 2, which are preferred but not necessarily exclusively in fluidized bed 1.
The conditioner 108, which corresponds substantially to the conditioner of the fluidized bed 1, need only be designed so that the air supplied by the blower 107 can be moistened if necessary. On the other hand, the second fluidized bed 101 serves to remove the residual hulls and the ends of the second fluidized bed 101 are cyclone 1
It is linked to 10. The air circuit of the cyclone 110 corresponds in principle to the air circuit of the cyclone 10, ie there is a blower 109 (similar to the blower 9) and a flap 112 is provided downstream (like the flap 12), and A flap 114 is also provided to regulate the amount of fresh air. From German Patent 2,354,617 it is also known to design the second fluidized bed 101 as a fluidized bed comminuter if desired.

After the screw conveyor 22, the mixture of grain and residue hull can also be fed to the air sorter 25 via the transport path 24. The air expelled at the top of the air sorter 25 then contains the skin residue and therefore must be cleaned, which can be done by the cyclone 110. However, the dwell time in the air sorter 25 is not sufficient to air condition the seeds (ie not enough to adapt the seed moisture and temperature to ambient conditions), so the lower end of the air sorter 25 It is appropriate to extend the air conditioning stage 26 for the grain exiting the. The air conditioning stage 28 is formed by means of a device 27 similar to a horizontal chiller, to which conditioned air is fed countercurrently from the inlet 28 or to equalize and cool the water content of the grain The grain is simply left in the state of the grain itself in the air conditioning cell 29 for a predetermined time, in which case the regulated air can be supplied to the blower 29 by the blower 30, at which time the air is discharged from the outlet. Eject from 31. Of course, the air conditioning cell
The cost of 29 is relatively low, but requires a relatively long downtime. The use of the second fluidized bed 101 is advantageous as long as air conditioning and sieving (subdivision) can be done simultaneously in a single device.

The components of FIG. 1 described above correspond to the prior art, but can be modified according to the prior art if desired.

The down time in the fluidized bed 1 can be kept very short and its cost can be kept very low, as compared to previous methods. This is achieved by the fact that the seeds fed to the fluidized bed 1 are strongly heated even with high efficiency even inside the grain. Above all, this is particularly advantageous for soybeans. This is because hairline crevices occur in the grain through which water passes from the grain to the outside, which has two effects. On the one hand, undesired enzymes such as antitrypsin or lipoxidase are at least partially destroyed within the grain and, on the other hand, the hulls are loosened by the steam flowing to the surface of the grain. Therefore, it is only necessary to have a relatively short treatment in the fluidized bed 1 and to remove the loosened rind in order to be able to expose still hot seeds to mechanical stress in stage 17. All that is necessary is to set the treatment in the fluidized bed 1 so as to maintain the seed temperature.

The cost would be even higher if the heating of the grain was done by convection heating according to the prior art. However, testing has shown that heating seeds by contact heating will significantly reduce the overall energy cost. To do this, it is possible to use a device 32 which is constructed, for example, like a vertical roaster but omits the usual cooling area at the end, which is the area required for a vertical roaster. Seeds fill the hopper 33 from the top and pass through a relatively thin tube of lamella. The metal of this tube 34 is a heating device from the outside.
It is heated by 35, which heating device comprises at least one blower 36, preferably two blowers at the diametrically opposite ends of the device 32. The blower 36 provides recirculated air within the device 32, but if the air is too dirty, a portion of it can be vented through an opening 37 closed by a flap. The placement of the filter 38 is appropriate because the air can be contaminated by the skin. The sheet metal of tube 34 can be perforated as is usual with vertical roasters. It is clear that the outer casing of the device 32 is properly isolated.

In this way, the seed contacts the hot surface of tube 34 while passing through device 32, first heating the outside of the bulk of the seed and transferring that heat to the inside. This is assisted by the circulating hot air which constitutes the heat carrier. As the seed travels along the hot tube of tube 34, the seed is subjected to mechanical friction, and water from the inside of the grain simultaneously exits the friable hull of the heat treatment, as described above. Nevertheless, the perforations in the tube 34 increase friction, especially when a bumpy surface of the seed is obtained at the edges of the perforations.

It has been found that about half of the seeds have already been released from the hull in the fluidized bed 1 by this treatment and that the hull need only be removed in the fluidized bed 1. Therefore, the down time in the fluidized bed 1 is considerably reduced compared to the past, and 2 minutes or less is suitable and 1 minute or less is preferable, but actually about 30 seconds to 50 seconds, for example, about 40 seconds. Seconds. This is about a quarter of the time required to date, and in some cases even less, thus saving the cost of heating the passing air. Furthermore, the temperature can be kept slightly lower than in known methods, preferably 130 ° C to 170 ° C.
In practice, a dwell time in the device 32 of up to 30 minutes is suitable, preferably 5 to 25 minutes. 15-25 in most cases
An excellent product is obtained with a rest period of minutes, but on average it takes about 20 minutes.

As already mentioned, most of the skin has already been loosened in the device 32. Since the tube 34 is suitably perforated, it is inevitable that a portion of the outer skin will enter the space surrounding the tube 34 and will be swirled by the flow of air generated by the blower 36. Therefore, by making the cross section of the device rectangular,
Advantageously, the air passing through the radiator 35 and the tube 34, which is also preferably of rectangular cross section, is forcibly guided through the filter 38 and cleaned by the filter. Nevertheless, it should be understood that the particles of the crust are easily straightened when they come into contact with hot surfaces and when the device 32 is overheated.
Therefore, at the end of the treatment with contact heat, the seeds are brought to an average temperature (so-called "bulk temperature") of at least about 60% of the temperature in the fluidized bed 1 which has to reach the end of the next treatment. That is convenient. On the other hand, for the reasons mentioned above, its temperature is 100% of the temperature at the end of the fluidized bed 1.
The following is appropriate. In fact, it is most effective to release the fluidized bed 1 from heating duty, and for that reason it is particularly advantageous if the seeds at the end of the device 32 have at least 70% of their temperature. Is about 75% to 85% at the outlet of the fluidized bed 1.

For obvious reasons, therefore, the cross-section of the tube 34 should be relatively narrow in the lateral dimension from the heating device 35 to the filter 38 shown in FIG. I have to. This is because when the tube 34 is dimensioned more broadly, heat is transferred little by contacting the interior of the seed stream and again convection heating occurs predominantly. In this way an uneven distribution of temperature can occur. Therefore, it is advantageous to use an apparatus which comprises an inwardly extending surface to be heated, especially when large quantities of seed have to be treated. In principle, for example, in the case of the device 32, it is possible to provide a radial sheet metal (in case the tube 34 has a circular cross section) which extends into the interior of the tube 34, but as already mentioned, it is preferably rectangular. Suitably, a cross section is used, in which case the sheet metal extends in the direction of seed flow.

A particularly advantageous design of the elements for constructing the device 232 (FIG. 3), which is similar to the device 32, is shown in FIG. Each of the elements 132 shown in FIG. 2 is preferably indented with a rectangular cross section and laterally has steam domes 39 and 40 on either side. The steam dome 39 has an inlet connection 41, and a steam conduit (not shown) from the boiler is connected to this connection pipe.
It can be connected via a flange 42 of 41. Dom 39
Inside there is a diff user plate 43 facing the inlet connection 41 for even distribution of steam into the dome 39.

Starting from the dome 39, a plurality of tubings 44 extend across the recessed area of the element 132, which provides a hot surface for seed contact over the entire cross section. For example, by staggering the tubing, individual seeds are deflected multiple times to contact their surfaces while at the same time abrading the already loosened hull.

On the other side, steam is collected from line 44. An outlet connection 45 is located at the bottom of the dome 40 for the necessary drainage of the condensate that will eventually occur.

Similar devices have been proposed, for example, in Russian patents 1,106,968 and 1,114,867, which are certainly applicable within the scope of the invention, but the structural elements shown in FIG. 2 differ according to the desired overall installation dimensions. It has the particular advantage of being able to manufacture sized devices. In fact, as you can see, the dome 39,4
0 does not extend the full height of the structural element 132, thus leaving a short tube on each side, and its arrangement is such that the tube on one side, e.g. the bottom side, is above the tube of another element. It is somewhat spread out so that it can be received and surrounded by pieces. Another possibility consists, of course, in that the tubes freely placed from the domes 39, 40 can be provided with connecting flanges for the respective subsequent structural element.

In this way, a preheater 232 according to FIG. 3 can be assembled, which preheater consists of four elements 132 preceded by an inlet element 46, to which the discharge device 48 is arranged.
And end elements 47 are connected. However, it should be mentioned that in some cases, as is the case with the installation according to FIG. 1, if the pocket wheel 6 of the fluidized bed device 1 also takes over this function, a separate discharge device can be dispensed with. I have to.

If the dwell time in the preheater is relatively short, it is advantageous to provide a heat maintenance zone connected to the preheater. In such heat-retaining areas, there is time left for water to come out of the seed or bean kernel and for the dehulling. The heat-maintaining zone can be formed, for example, by a bin or cell which does not have to be operated in batches and which can continuously receive seeds from above and continuously extract seeds at the bottom after the initial filling time. If this is difficult to achieve due to the vertical arrangement, it is also possible to provide a horizontal cell 49 which is well isolated and is provided with a conveyor, for example the chain conveyor 102. If it is necessary to feed the seeds from the bottom end of the device 232 to the fluidized bed device 1 arranged at the same height, it is advantageous to design a cell such as a vertical or inclined conveyor. . In this way, such cell 49 serves a dual function. Such cells 49 also serve to discharge seeds from the preheater 232 on behalf of the discharging device 48, so that additional functions can be assigned to the cells 49. The dwell time in the preheater 232 is then substantially determined by the speed of the chain conveyor 102, as the amount of seed flowing from above depends on the discharge speed of the chain conveyor 102 at the bottom of the device 232.

Example: A soybean hull having the same equipment as that shown in FIG. 1 was taken. First
The illustrated device 32 was only replaced by the device 232 of FIG. Another change with respect to FIG. 1 was that the air sorter preceded the second fluidized bed 101.

Soybeans had an average water content of 11.2% and were at ambient temperature. These beans passed through device 232 within a 20 minute rest period. The water content of the beans at the end of the preheater 232 is reduced by 0.2%,
The average temperature was 55 ° C.

The beans were then introduced into fluidized bed 1 where they were processed for 30 seconds only. The temperature of the air to be treated reached 160 ° C. At the end of this treatment the beans were close to a water content of 10.6% at a temperature of 84 ° C. At this point, it must be said that the temperature reading above represents the average temperature. This is because the difference between the temperature inside the grain and the temperature around it occurs after the treatment in the fluidized bed. The average temperature is measured after the seed has had sufficient time to even out the temperature in the isolated container. After fluidized bed 1, about half of the seeds were already dehulled and the residual hulls were then removed by step 17, air sorter 25 and second fluidized bed 101.

After this treatment, the dehulled soybeans had a soft surface and because of the fluidized bed (compared to the method according to German Patent 2,354,617, which already saves a lot of money by heating only the bean surface). Although they could save 80% of their energy, some of these savings had to be spent heating the preheater 232, thus saving 30% of the total cost.

The soybeans obtained from this treatment were not extensively free of harmful enzymes such as antitrypsin, which can be attributed to the fact that these substances were already destroyed at temperatures around 80 ° C. When soybeans are cooked at any time (eg for human food), the soybeans are kept in a fluidized bed at 70 ° C.
It would be even more convenient to heat only to an average temperature of ~ 80 ° C. However, if the antitrypsin is destroyed, it is better to choose a temperature of about 80 ° C, but for energy reasons only, it is preferable to choose a temperature not exceeding 90 ° C.

Following this treatment, the same example was repeated with seeds at different temperatures and different water contents, whereby it was found that the range of parameters recited in the claims was appropriate.

In the embodiment of FIG. 2, the domes 39, 40 represent the jacket of the device for actually circulating the heat carrier, but in the first-mentioned embodiment it is the device 32 which surrounds the tube 34 which serves as the jacket. 2 is an outer casing (FIG. 1) of FIG.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a dehulling facility according to the invention, FIG. 2 is a diagram showing the components that make up a particularly preferred apparatus for treating with contact heat, and FIG. 3 is of the embodiment shown merely by way of example. It is a figure. 1 …… First fluidized bed 17 …… Skin removing device 32 …… Preheating device 101 …… Second fluidized bed

Claims (14)

[Claims] 1. A bean-like seed having a husk surrounding the husk, comprising the steps of heating the seed to a predetermined temperature inside the husk and exposing the seed to mechanical stress to separate the husk. In the method of removing hulls, especially soybean hulls, the heating step is carried out as follows: a continuous dense stream of seeds is gradually guided through a closed longitudinal passage to contact the hot surface of the passage. By preheating to the inside of the kernel and subsequently heating or maintaining the seeds in a stream of hot gas to heat or maintain them at a predetermined temperature, thereby exposing them to mechanical stress during the subsequent separation of the husks. A method characterized by being able to do. 2. The method according to claim 1, wherein substantially all the surface of the seed is contacted with the hot surface or with the surface heated by said hot surface. 3. The method of claim 1 wherein seeds are contacted by another hot surface within the hollow structure that is the passageway formed by said hot surface. 4. After the steps of treating with contact heat and with a stream of hot gas, the various are exposed to mechanical stresses, in particular by applying at least one impact, to the claims 1 to 3. The method according to any one of the above. 5. At the end of the treatment with contact heat, the seeds are brought to a temperature of at least about 60% of the temperature at which the end of the next treatment must be reached before the last dehulling step,
Preferably, the seeds are brought to a temperature which is below 100%, in particular up to at least 70%, suitably up to a temperature in the range of 75% to 85%. The method described in any one of. 6. The method according to claim 1, wherein the step of treating with contact heat is carried out for a maximum of 30 minutes, preferably 5 to 25 minutes, in particular 15 to 25 minutes, for example 20 minutes. The method described in any one. 7. The method according to claim 1, wherein the seed is treated with contact heat to bring the seed to an average temperature of 50 ° C. to 75 ° C., preferably to a temperature of the order of 60 ° C. The method described in any one of the above. 8. A seed, after the step of treating the seed with contact heat,
In particular soybeans, 70
A process according to any one of claims 1 to 7, wherein the average temperature is between 0 ° C and 90 ° C, preferably up to about 80 ° C. 9. After the step of treating with contact heat, the step of treating in a stream of hot gas in less than 2 minutes, preferably in less than 1 minute, in particular in 30 to 50 seconds, for example in about 40 seconds. A method according to any one of claims 1 to 8 for performing. 10. After treatment with contact heat and before treatment with a stream of hot gas, the seeds are kept hot for a predetermined time, for example in a bin or cell, said predetermined time being preferably 20.
Method according to any one of claims 1 to 9, which is less than or equal to minutes, in particular less than or equal to 15 minutes, in particular less than or equal to about 10 minutes. 11. A device for carrying out a method for removing a bean-like seed hull, in particular a soybean hull, having a hull surrounding a grain, at least one for treating the seed in a stream of hot gas. A first fluidized bed and at least a dehulling device for applying mechanical stress to the seeds after the first fluidized bed, comprising a preheating device upstream of the first fluidized bed. The preheating device is characterized in that it is formed as an elongated closed passage for gradually guiding a continuous dense flow of seeds, the passage having a surface to be heated. 12. The preheating device preferably has a casing structure, which is a closed passage for guiding the seeds, which extends under the influence of gravity and thus in particular in the vertical direction, which casing structure heats up. The device of claim 11 having a textured surface. 13. A casing structure having a heated surface extending therein, preferably transverse to the inside,
13. The device according to claim 12, wherein the casing structure is formed in particular like a seed dryer. 14. A second fluidized bed is provided after the mechanical skinning device, especially after the impact skinning device.
Device according to any one of claims 11 to 13.