Method and system for hygienization of plant based kernels and grain

Abstract

A method of hygienization of plant-based kernels and grain for use as seed, food, food-stuff, or feed, using a heated humid atmosphere, and a corresponding system for hygienization of plant-based kernels or grain are disclosed. The method comprises a heat treatment step wherein the kernels or grain being heat treated in the heated humid atmosphere are advanced step-wise while being subjected to infrasound. Heat and moisture from the heated plant-based kernels or grain can be recovered and used in the method.

Description

[0001] METHOD AND SYSTEM FOR HYGIENIZATION OF PLANT BASED KERNELS AND GRAIN

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a method of treatment of plant-based kernels or grain, and more particularly to a method of hygienization of plant-based kernels and grain for use as seed, food, foodstuff, or feed, using a heated humid atmosphere, and a corresponding system for hygienization of plant-based kernels or grain, which method comprises a heat treatment step wherein the kernels or grain being heat treated in the heated humid atmosphere are advanced step-wise while being subjected to infrasound. After heat treatment, heat and moisture from the heated plant-based kernels or grain are preferably recovered and used in the method.

[0004] BACKGROUND ART

[0005] Hot water treatment has traditionally been used in the prior art for disinfection of seed. Treatment with water however typically increases the moisture content of the seed, and accordingly requires drying of the seed in order to reduce the moisture content to a level allowing for storage of the seed. Such drying is however rather energy-demanding.

[0006] WO 2016 / 198644 discloses a seed disinfection method comprising contacting seed with a treatment composition comprising at least one disinfecting agent and / or liquid component; and thereafter or at least partly simultaneously, exposing said seed to a treatment atmosphere for an exposure time of at least 1 s, wherein the treatment atmosphere has a relative humidity of at least 50 % and temperature of least 40°C.

[0007] WO 97 / 38734 discloses a heat treatment process for disinfection of seeds from pathogens and other undesirable fungi and bacteria. The process disclosed therein uses non-wa- ter-borne heat for heating the seed. The seed is heated from the outside and in. According to a preferred embodiment heat is supplied to the seed using hot air having an air moisture content that prevents a decrease or increase of the moisture content of the seed. The invention disclosed in WO 97 / 38734 avoids the need for drying the seed after treatment.

[0008] In the prior art methods, however, the residence time of the grain may be difficult to control. Also, fluctuations or variations of other desired parameters, such as humidity and temperature may occur throughout the treatment. It would be desirable to provide a method wherein residence time of the grain can be closely controlled, and wherein variations of temperature and humidity can be reduced. Preferably, the need for an expensive drying step should be avoided.

[0009] It is an object of the present invention to provide such a method.

[0010] SUMMARY OF THE INVENTION

[0011] According to the present invention, the object has been solved by means of a method wherein kernels or grain are subjected to a humid heated atmosphere and are advanced through the humid heated atmosphere in a controlled step-wise manner while being subjected to infrasound.

[0012] Accordingly, in a first aspect the present invention relates to a method of treating kernels or grain for use as food, foodstuff, feed, or seed, comprising the following steps: A a feeding step, wherein kernels or grain to be treated are fed to the method; B a heating step, wherein the kernels or grain are subjected to heat, so as to heat the kernels or grain to a desired temperature; C a heat-keeping step, wherein the heated kernels or grain from step B are kept in a heated state during a predetermined period of time; D a drying step, wherein the heated kernels or grain from step C are dried; and, E a discharging step, wherein the cooled kernels or grain from step D are discharged from the method, wherein, in feeding step A, the kernels or grain are fed to a feeding end 110 of a heat treatment chamber 100; in heating step B, and in heat-keeping step C, the kernels or grain are kept on at least one perforated tray 170, arranged at a first level in height in the heat treatment chamber 100, said at least one perforated tray 170 being configured to be controllably positioned in either a grain holding position or in a grain passing position, are subjected to a humid heated atmosphere within the treatment chamber; in steps B and C, the kernels or grain are advanced through the heat treatment chamber step-wise gravitationally towards a discharging end 120 of the heat treatment chamber; and, in that the kernels or grain in steps B and C are subjected to infrasound.

[0013] In another aspect the invention relates to a system 10 for treatment of kernels or grain for use as food, foodstuff, feed, or seed, which system comprises: a heat treatment chamber 100 having a first end 110 and a second end 120; a feeding unit 105 configured to receive kernels or grain to be treated, and to feed to the treatment chamber 100 the kernels or grain to be treated; said heat treatment chamber comprising: a first inlet 130 configured to receive a heating fluid; a second inlet 140 configured to receive kernels or grain from the feeding unit 105; and, a first outlet 150 configured to discharge heat treated kernels or grain from the heat treatment chamber, said heat treatment chamber being configured to heat the kernels or grain using sensitive heat carried by the heating fluid being fed to the chamber by contacting the kernels or grain with the heating fluid, and to keep the kernels or grain heated for a predetermined period of time; wherein the first end 110 is an upper end of the heat treatment chamber; the second end 120 is a lower end of the heat treatment chamber; the heating fluid is heated steam; the second inlet 140 configured to receive kernels or grain is located in the upper end 110 of the heat treatment chamber 100; the first outlet 150 configured to discharge heat treated kernels or grain from the heat treatment chamber is located in the lower end of the heat treatment chamber; the heat treatment chamber 100 additionally comprises at least one perforated tray 170, arranged at a first level in height in the heat treatment chamber, said at least one perforated tray being configured to be controlla- bly positioned in either a grain holding position or in a grain passing position; and, wherein the heat treatment chamber 100 is connected to a source of infrasound 180 configured to produce an infrasonic sound wave in the heat treatment chamber.

[0014] By virtue of the infrasound in the heat treatment chamber 100, grains or kernels on a perforated tray 170 will be displaced, and may preferably even be essentially fluidized. The displacement and mixing of the grain thereby caused will improve the exposure to heat of the kernels or grain on the perforated tray, and also improve the homogeneity of the exposure of the kernels or grain to heat and humidity.

[0015] By virtue of the perforated tray 170 being controllably positioned in either a grain holding position or in a grain passing position, the perforated tray 170 may be shifted from a grain holding position to a grain passing position, such as by being withdrawn from the chamber, rotated into a vertical position, or tilted, such that grains from such perforated tray 170 will fall to a next lower tray, such as another lower perforated tray 170, positioned in a grain holding position in the heating chamber. By allowing the kernels or grain to progress through the treatment chamber 100 in discrete steps, from one upper perforated tray 170 to another lower tray, such as another lower perforated tray 170, the residence time of the kernels or grain in the heat treatment chamber can be closely regulated. Also, the residence time distribution of the kernels or grain in the heat treatment chamber 100 can be kept narrow.

[0016] In a preferred embodiment, the system 10 additionally comprises: a drying chamber 200 configured to dry, and, preferably, also to cool, heat treated kernels or grain discharged from the heat treatment chamber; and, a feeding unit 205 configured to receive kernels or grain discharged from the heat treatment chamber 100 and to feed to the drying chamber 200 kernels or grain to be dried, and preferably also be cooled.

[0017] In a preferred embodiment, the drying chamber 200 of system 10 comprises: an upper end 210; a lower end 220; a first inlet 230 configured to receive a flow of dry air, preferably ambient or cool dry air, said first inlet preferably being provided in one end of the drying chamber 200, and more preferably in the lower end of said drying chamber; a second inlet 240 located in the upper end configured to receive kernels or grain from the feeding unit 205; a first outlet 250 configured to exiting heated humid air from the drying chamber, said first outlet preferably being located in an opposite end of the drying chamber, and more preferably in the upper end of said drying chamber; a second outlet 260 located in the lower end configured to discharge cooled kernels or grain from the drying chamber 200; and, at least one perforated tray 270, arranged at a first level in height in the drying chamber 200, said at least one perforated tray being configured to be controllably positioned in either a grain holding position or in a grain passing position, and wherein the drying chamber 200 is connected to a source of infrasound 280 configured to produce an infrasonic sound wave in the drying chamber.

[0018] The inventive system 10 preferably additionally comprises a heat and water recovery unit 60 configured to recover heat and moisture from a flow of heated humid air exiting from the heat treatment chamber 100, or from a flow of heated humid air exiting a drying chamber 200, or from both.

[0019] The inventive method has an extremely low energy demand and an extremely low water demand. At the same time, the inventive method allows for subjecting the kernels or seed to a cooling liquid, which liquid may be supplemented with desired substances to be provided to the kernels or grain, and which liquid may be aqueous, e.g. water-based. No electromagnetic radiation, such as microwaves, is required in the inventive method.

[0020] Further embodiments and advantages of the invention will be apparent from the following detailed description and appended claims.

[0021] The term "seed" is used herein to refer to plant-based kernels or plant-based grain for planting or sowing purposes. For seed purposes the kernels or grain must be capable of germination.

[0022] The terms "plant-based kernels" and "plant-based grain" are used herein to refer to plant-based kernels, and plant-based grain for use as human or animal nutrition, e.g. food, foodstuff, and feed. For such nutrition purposes the kernels or grain do not need to be capable of germination. The terms "plant-based kernels and plant-based grain" and "kernels and grain" will be used interchangeably herein.

[0023] The invention is intended for use with plant-based kernels and plant-based grain, either for planting or sowing purposes, or for human or animal nutrition purposes.

[0024] The term "hygienization" is used herein to denote a heat treatment process using sensitive heat carried by heated steam or water, wherein kernels or grain are subjected to heated steam or water, and wherein the heat is sufficient to disinfect the kernels or grain, so as to make the kernels or grain suitable for use as food, foodstuff, or feed. During hygienization as defined herein, the kernels or grain are heated from the outside by exposing the outside of the kernels or grain to sensitive heat, such as carried by steam, which may condense on the outside of the kernels or grain to be heated, thereby heating the kernels or grain. Preferably, the heat used during such hygienization is not damaging to the germination of the seed. Thereby, kernels or grain suitable for use as seed can be obtained. Preferably, the hygienization does not damage a protein structure of a protein contained in the kernels or grain to be treated. Hygienization is less severe than other conventional treatments, such as e.g. pasteurization, which will typically be damaging to germination of the seed and to proteins contained in the seed. The term "infrasound", and "infrasonic sound wave" is intended to refer to a sound wave of a frequency of up to 20 Hz, and preferably below 20 Hz.

[0025] BRIEF DESCRIPTION OF THE ATTACHED DRAWING

[0026] Figure 1 shows the principal layout of a preferred embodiment of a system 10 of the invention, including a heat treatment chamber 100, a drying chamber 200, and heat and moisture recovery unit 60. The heat treatment chamber 100 exhibits a first inlet 130 configured to enter a combined flow of heated steam and air from the heat and moisture recovery unit 60. A belt conveyor 300 configured to transport heat treated kernels or grain from heat treatment chamber 100 to a drying chamber 200 is also included. Arrows indicates the direction of movement of the belt of the belt conveyor. Inspection windows 190, and 290, respectively, are included for facilitated inspection of the extent of displacement and fluidization of kernels or grain on perforated trays 170, and 270, respectively. In FIG. 1, for a better visibility of the perforated trays 170 and 270, all perforated trays are shown in their withdrawn, grain passing position. The embodiment shown in FIG. 1 includes 10 perforated trays 170 in the heat treatment chamber 100, and 10 perforated trays 270 in the drying chamber 200.

[0027] DETAILED DESCRIPTION OF THE INVENTION

[0028] Any kernels or grain can be treated using the inventive method, such as grains, beans etc. The different steps included in the method of the invention, and also the inventive system, will be described in closer detail hereinafter.

[0029] Step A -feeding step

[0030] In step A the kernels or grain to be heat treated are fed to the method, i.e. into the heat treatment chamber 100. In step A the volume of kernels or grain to be treated is regulated. Step A may also include sifting of the kernels or grain, e.g. such as to exclude kernels or grain exceeding certain measures. The kernels or grain to be fed to the process is preferably provided at ambient temperature. The feeding is preferably carried out step-wise by feeding a predetermined amount to a discrete highest level in the heat treatment chamber 100. When the kernels or grain on the highest level has been transferred to the level next below in height in the heat treatment chamber 100, the highest level can be filled again with yet a predetermined amount of the kernels or grain to be hygienized. Step B - heating step

[0031] In step B the kernels or grain fed to the heat treatment chamber 100 are subjected to a heated humid atmosphere, so as to heat the kernels or grain. The kernels or grain to be heated is preferably provided at ambient temperature. Heating of the kernels or grain to the desired temperature, is typically accomplished on the perforated tray 170 on the first, i.e. highest level, or, when included, on the perforated tray 170 on the second or third lower level in height in the heat treatment chamber 100.

[0032] Step C - heat-keeping step

[0033] As the kernels or grain fed to the heat treatment chamber 100 is advanced step-wise, from the level of one perforated tray 170, to another lower level, such as to the level of another lower perforated tray 170, down through the heat treatment chamber, and the kernels or grain has become heated to the desired temperature, e.g. on the 1stto 3rdlevel, the overall residence time spent by kernels or grain on the remaining lower levels will correspond to heat-keeping at the desired temperature.

[0034] The required heat for heating step B and heat-keeping step C can be provided by a flow of heated steam fed into the heat treatment chamber 100. If required, additional heating may be provided by electrical resistive heating in the heat treatment chamber 100. If required, additional heating may be provided by a flow of heated air being entered into the heat treatment chamber 100. When used, the flow of heated air could be combined with the flow of heated steam. It is believed that a major part, or preferably even all, of the required heating for the heating step B and heat-keeping strep C will be provided by the heated steam.

[0035] The combined duration of the heating step B and heat-keeping step C, corresponding to the residence time of the kernels or grain in the heat treatment chamber 100, should be kept short in order not to overly heat the inside of the kernels or grain. Generally, a lower temperature of the heated humid atmosphere in the heat treatment chamber will require a longer time of exposure of the kernels or grain to the heat during the heating step B and heat-keeping step C. Also, at a given temperature, a larger size of an average-sized individual kernel or grain will require a longer time of exposure to the heat. The temperature of the flow of heated steam being supplied to the heat treatment chamber is preferably kept at a predetermined temperature within a range of 60-100°C, more preferably within a range of 60-80°C. The overall temperature of the heated humid atmosphere in the heat treatment chamber should also be kept within similar general ranges. For a facilitated control of the relative humidity of the heated heat treatment atmosphere within the heat treatment chamber, a flow of air can be entered into the heat treatment chamber. The temperature of the flow of air being entered could be ambient, or higher if additional heating is desired. When a flow of air is being entered into the heat treatment chamber, the temperature of a flow of heated humid air exiting from the heat treatment chamber should preferably be controlled so as to be within the range of 60-80°C. It is preferred to perform the heating step B and heat-keeping step C at an atmospheric pressure. Any evaporation or loss of water from the kernels or grain should be minimized and preferably avoided in steps B and C. The combined period of time of steps B and C, and hence also the residence time in the heat treatment chamber 100 will typically be kept within the range of 1-10 minutes, e.g. 1-3 minutes. The temperature and duration of steps B and C will be selected dependent on the characteristics of the particular kernels or grain being treated, and preferably, dependent on the characteristics of the specific batch of the kernels or grain being treated.

[0036] The heat in steps B and C predominantly affects the outer portion of the kernels or grain, where any undesired contamination typically is located, while the inner portion thereof, wherein the protein located, is not heated and is thereby not negatively affected. The inventive heat treatment (i.e. steps B and C) is capable of sanitizing the kernels or grain against salmonella, listeria, E. Coli etc., and also against seed-borne diseases, enhanced peeling, reduces antinutrients, positively effects taste, preserves protein values, and hence improves the food quality of the kernels or grain to be treated.

[0037] Step D - drying step

[0038] Before the heat treated kernels or grain from the heat keeping step C are discharged from the method, the heat treated kernels or grain from the heat keeping step C should be dried in a drying step D. The dried kernels or grain exiting drying step D should preferably exhibit a temperature of about 20°C and a desired water content, suitable for storage, of the kernels or grain, typically of about 13-15 %. The resulting water content can be regulated e.g. by means of the duration of the drying step D, which may, e.g., be controlled by means of the speed of conveyance of the kernels or grain through the drying step D.

[0039] In a preferred embodiment of drying step D, the kernels or grain from the heat keeping step C are contacted with a flow of ambient or cool dry air in a drying chamber 200, so as to dry the kernels or grain. In step D the kernels or grain are preferably advanced step-wise through the drying chamber 200 in a direction essentially opposite to a direction of the flow of ambient or cool dry air in the drying chamber 200. As the flow of ambient or cool dry air propagates over the kernels or grain in the cooling step D the flow of air will absorb heat and moisture from the kernels or grain, while the kernels or grain, on the other hand, preferably propagating in an opposite direction, will become cool and dry. The ambient or cool dry air entering step D preferably exhibits a temperature of about 20°C, and a relative humidity (RH) of about 50 %. The heated humid air leaving from step D preferably exhibits a temperature of about 50°C, and an RH of about 90-100 %. The kernels or grain are preferably advanced through the drying chamber gravitationally towards a lower discharging end of the drying chamber. In preferred embodiments, the kernels or grain in the drying step D are subjected to infrasound. In the drying step D, the residence time of the grain in each individual level in the drying chamber 200 is regulated so as to correspond to a predetermined value.

[0040] In the drying step D, if required, additional heating could be provided in the drying chamber by electrical resistive heating.

[0041] Step DCOOL - rapid cooling by application of a cooling liquid

[0042] Prior to drying step D, the heat treated kernels or grain from the heat treatment are preferably rapidly cooled in a cooling step DCOOL, thereby stopping or quenching the heattreatment process of the kernels or grain. The cooling liquid can advantageously be used for supplementing the kernels or grain with a desired substance. The cooling liquid is typically aqueous, and may contain, in addition to water, a substance desired to be added to the kernels or grain, such as a growth stimulant, a disinfectant, H2O2, microorganisms, sulphur etc. The duration of contact with the cooling liquid in step DCOOL should be kept to a minimum, e.g. a few seconds, typically 1-5 seconds. The pores of the kernels or grain tend to be in a more open state after the heat treatment in the humid atmosphere, and addition of a desired substance to the kernels or grain at this state in the method while the pores are still open is therefore believed to be especially efficient.

[0043] Step F - moisture and heat recovery step (air cooling and dehumidifying step)

[0044] In order to reduce water consumption and energy requirements, the inventive method preferably comprises a heat and moisture recovery step F. In step F, heat and moisture from a flow of humid air exiting from the heat treatment chamber 100, or from the flow of heated humid air exiting from the drying step D are recovered, and preferably from both the heat treatment chamber 100 and step D. The flow of heated humid air exiting from drying step D is cooled and dehumidified in step F. Thereby, a flow of ambient or cool dry air is obtained. The flow of ambient or cool dry air obtained in step F is provided to step D. In step F, water removed from the heated humid flow of air exiting from drying step D, is preferably heated and provided in the form of heated steam to heat-keeping step C and heating step B. Suitable technologies for continuous cooling and dehumidifying of a flow of humid air, such as the heated flow of humid air exiting from drying step D, are known in the art. Such technologies may e.g. use a water adsorbing material, such as a liquid desiccant, for adsorbing water from the heated flow of humid air exiting from drying step D. The water adsorbing material having absorbed water may be regenerated by heating the water adsorbing material, thereby removing the absorbed water therefrom. Heated water or steam from step F, resulting from regeneration of the water adsorbing material is preferably provided in the form of heated steam to heat-keeping step C and heating step B. In a preferred embodiment, step F utilizes a liquid desiccant as the water adsorbing material. A particular useful and energy efficient technology has been developed by Airwatergreen AB (SE). Suitable air cooling and dehumidifying units which can be used in step F are available from Airwatergreen AB, e.g. under the trade designation NEXT-S. The technology has been described in more detail in WO 2018009125 Al.

[0045] The system

[0046] The feeding unit 105 is configured to intermittently feed, such as by metering, controlled amounts of kernels or grain to be treated into the treatment chamber 100 through the second inlet 140. The kernels or grain fed from the feeding unit 105 into the heat treatment chamber 100 will be received therein by the upmost perforated tray 170 which is in a grain holding position. The at least one perforated tray 170 is configured to be independently individually regulated into a grain holding or grain passing position. In its grain holding position, the perforated tray is in an essentially general horizontal position, while in its grain passing position, the perforated tray can be in a substantially tilted or essentially general horizontal position. In a preferred embodiment, the at least one perforated tray 170 is configured to be brought into a grain passing position by being withdrawn from the heat treatment chamber 100. This embodiment allows for a reduced distance in height between two neighbouring perforated trays 170. The number of perforated trays 170 in the heat treatment chamber 100 will be selected dependent on the height of the heat treatment chamber, the capacity of the source of infrasound 180, and the intended capacity of the heat treatment chamber. A higher number of perforated trays 170 will usually correspond to a higher capacity of the heat treatment chamber. The number of perforated trays 170 arranged in the heat treatment chamber 100 will typically be at least 2, at least 3, or at least 4, such as 3-20, or 4-20, e.g. about 10, arranged at different levels of height in the heat treatment chamber 100 (i.e. the first perforated tray 170 at a first level, a second perforated tray 170 at a second, lower, level, a third perforated tray 170 at a third, even lower, level, etc). It is believed that embodiments with merely one perforated tray 170 (at a first level), or merely two perforated trays 170 (at a first level, and a second lower level, respectively), will be useful for experimental purposes, such as for identifying proper settings for the inventive method and system, while embodiments having three or more perforated trays 170 (at three or more different levels), will be useful in carrying out the invention for intended production purposes. The maximum limit of the number of perforated 170 trays will typically be governed by the height of the heat treatment chamber, and the capacity of the source of infrasound 180. The trays 170 are perforated so as to allow for a flow of heated humid air to pass from beneath a tray in its grain holding position, up through the openings of the perforations (not shown) of the tray, and preferably also so as to maximise the potential surface of the kernels or grain on the tray 170 that can be exposed to the flow of heated humid air flowing through the perforations in said tray 170. The heat treatment chamber 100 is preferably disposed in an essentially vertical direction. Especially for kernels or grain of a small size, the trays 170 may be formed from a net or mesh, such as a metal net or mesh. The openings of the net or mesh should be sufficiently small so as to prevent passage of a kernel or grain through such opening. There should be no opening in a perforated tray 170 through which opening a kernel or grain to be treated could pass. (Obviously, the latter requirement also applies to a perforated tray 270 in a drying chamber 200.)

[0047] In a preferred embodiment, one or more inspection windows 190 are included in the heat treatment chamber 100 for facilitated inspection of the extent of displacement and fluidization of kernels or grain on the perforated trays 170.

[0048] A separate inlet (not shown) configured to receive and enter a flow of air into the heat treatment chamber may be included in the heat treatment chamber 100. Alternatively, the first inlet 130 may additionally be configured to receive and enter into heat treatment chamber 100 such flow of air. For example, in embodiments wherein the first inlet 130 is additionally configured to receive and enter into heat treatment chamber 100 a flow of heated air, heated air may be introduced into the heat treatment chamber via first inlet 130 in admixture with the heated steam, e.g. in the form of a flow of heated humid air.

[0049] In a preferred embodiment, the first inlet 130 configured to receive and inject a heating fluid into the heat treatment chamber 100 is located in the lower end 120 of the heat treatment chamber 100.

[0050] In a preferred embodiment, for an enhanced control of a flow of air through the heat treatment chamber 100, e.g. in instances where the infrasound is not sufficient to distribute the heated steam in the heat treatment chamber, a separate inlet configured to receive and inject a flow of air, or a combined inlet 130 configured to receive and inject both a flow of air and a flow of steam into the heat treatment chamber 100, and a second outlet 160 configured to exit a flow of heated humid air, is provided in the heat treatment chamber 100. For a more controlled flow of injected air through the heat treatment chamber 100, the separate inlet configured to receive and inject a flow of air, or the combined first inlet 130 configured to receive and inject both a flow of air and a flow of steam, is / are the located in the lower end 120 of the heat treatment chamber 100, while the second outlet 160 configured to exit a flow of heated humid air, is located in the upper end 110 of the heat treatment chamber 100.

[0051] In preferred embodiments, one or more resistive electrical heating elements (not shown) are provided on the inner wall of the heat treatment chamber 100. When required, such resistive electrical heating elements can be used for providing additional heating to the heated humid atmosphere, e.g. in instances when the heat carried by the heated steam being entered into the heat treatment chamber is not sufficient for maintaining a desired temperature in the heated humid atmosphere within the heat treatment chamber 100.

[0052] The source of infrasound 180, e.g. an infrasound generator, such as a pulsator, is operationally connected to the internal volume of the heat treatment chamber 100, such as by tubings 183 and 185. The source of infrasound is configured to produce an infrasonic sound wave in the heated humid atmosphere in the heat treatment chamber 100. The infrasonic sound wave should be controlled so as to cause desired displacement of kernels or grain on a perforated tray 170 in the heat treatment chamber. A suitable pulsator 180 can be based on a reciprocating piston, or a membrane causing an oscillating or reciprocating air flow connected to the heat treatment chamber 100 via tubings 183 and 185. While in principle one connection for infrasound could be used, it is presently preferred to use two connections at different locations on the heat treatment chamber. While generally less preferred, the source of infrasound 180 could alternatively be located inside the treatment chamber 100, or positioned in a wall thereof, such as in the case of a membrane.

[0053] The source of infrasound 180 is connected to the heat treatment chamber 100 at two different locations of the heat treatment chamber lOO.The locations are primarily selected depending on which trays are to be subjected to infra sound. Preferably, the source of infrasound 180 is connected to the heat treatment chamber 100 at a first position in height above the at least one perforated tray 170, and, at a second position in height below the at least one perforated tray 170. Accordingly, in a case wherein the heat treatment chamber 100 comprises two or more perforated trays 170, all of which are intended to be subjected to infra sound, the source of infrasound 180 is preferably connected to the heat treatment chamber 100 at a first position in height above the perforated tray 170 which is arranged at the highest level of height in heat treatment chamber 100, and, at a second position in height below the perforated tray 170 which is arranged at the lowest level of height in heat treatment chamber 100. In a case wherein the heat treatment chamber 100 comprises two or more perforated trays 170, only the highest two or three of which are intended to be subjected to infra sound, the source of infrasound 180 is preferably connected to the heat treatment chamber 100 at a first position in height above the perforated tray 170 which is arranged at the highest level of height in heat treatment chamber 100, and, at a second position in height below the second perforated tray 170 which is arranged at the lower level of height in heat treatment chamber 100, or at a second position in height below the third perforated tray 170 which is arranged at a third, lower level of height in heat treatment chamber 100, respectively. It is believed to be generally preferred to connect the infrasound to the heat treatment chamber 100 at a first position in height above the perforated tray 170 of the highest level in the heat treatment chamber 100, and at a second location below the above the perforated tray 170 of the lowest level in the heat treatment chamber 100. Thereby, all perforated tray 170 in the heat treatment chamber will be subjected to infrasound.

[0054] The heat treatment chamber 100 is preferably tubular, exhibiting a uniform cross section, e.g. circular or rectangular, along the length thereof in which the trays 170 are distributed at different levels of height.

[0055] In preferred embodiments, the system 10 additionally comprises an upper lock (not shown), configured to seal off the heat treatment chamber 100 and atmosphere therein from seed or grain yet to be treated, and to allow entry into the heat treatment chamber 100 of a desired portion of seed or grain to be treated. Such lock could for example constitute two trays, i.e. an upper tray, and a lower tray, e.g. similar to the trays 170, only without any perforations.

[0056] In preferred embodiments, the system 10 additionally comprises a lower lock (not shown), configured to seal off the heat treatment chamber 100 and atmosphere therein from seed or grain having exited the heat treatment chamber 100, and to allow withdrawal of a desired portion of heat treated seed or grain to be exited from the heat treatment chamber 100. Such lock could for example constitute two trays, i.e. an upper tray, and a lower tray, e.g. similar to the one or more trays 170, only without any perforations.

[0057] In a preferred embodiment, the system 10 additionally comprises a drying chamber 200 configured to dry, and, preferably, also to cool, kernels or grain discharged from the heat treatment chamber, and, a feeding unit 205 configured to receive kernels or grain discharged from the heat treatment chamber 100 and to feed to the drying chamber 200 kernels or grain to be dried, and preferably also be cooled. In a preferred embodiment of the inventive system 10, the drying chamber 200 is disposed in an essentially vertical direction, wherein seed is fed into an upper end 210, and discharged from a lower end 220 of said drying chamber.

[0058] The drying chamber 200 and feeding unit 205 are suitably configured similarly to the heat treatment chamber 100 and feeding unit 105, and the drying chamber also preferably comprises a source of infrasound 280 operationally connected to the drying chamber 200. Accordingly, the feeding unit 205 is preferably configured to intermittently feed, such as by metering, controlled amounts of heat treated kernels or grain to be dried into the drying chamber 200 through the second inlet 240. The kernels or grain fed from the feeding unit 205 into the drying chamber 200 will be received therein by the upmost tray 270 which is in a grain holding position. The trays 270 in the drying chamber 200 can be configured similarly to the trays 170 in the heat treatment chamber 100. Accordingly, the trays 270 are preferably configured to be independently individually regulated into a grain holding or grain passing position. In its grain holding position, a tray is in an essentially general horizontal position, while in its grain passing position, the tray can be in a substantially tilted or essentially general horizontal position. In a preferred embodiment, the trays 270 are configured to be brought into a grain passing position by being withdrawn from the drying chamber 200. This embodiment allows for a reduced distance in height between to neighbouring trays. The number of trays in the drying chamber 200 will be selected dependent on the height of the drying chamber, and the capacity of the source of infrasound 280, the intended capacity of the drying chamber. A higher number of trays will usually correspond to a higher capacity of the drying chamber. The number of trays will typically be at least 3, such as 3-20, e.g. about 10, and may typically be selected so as to be similar to the number of trays 170 in the heat treatment chamber 100. The maximum limit of the number of trays will typically be governed by the height of the drying chamber, and the capacity of the source of infrasound 280. The trays are perforated so as to allow for the flow of ambient or cool dry air to pass from beneath up through the openings of the perforations (not shown) of the trays, and preferably also so as to maximise the potential surface of the kernels or grain on a tray that can be exposed to the flow of ambient or cool dry air flowing through the perforations in said tray. The drying chamber 200 is preferably disposed in an essentially vertical direction. Especially for kernels or grain of a small size, the trays 270 may be formed from a net or mesh, such as a metal net or mesh. The openings of the net or mesh should be sufficiently small so as to prevent passage of a kernel or grain through such opening.

[0059] In a preferred embodiment, inspection windows 290 are included in the drying chamber 200 for facilitated inspection of the extent of displacement and fluidization of kernels or grain on trays 270.

[0060] For a more controlled flow of injected ambient or cool air through the drying chamber 200, the inlet 230 configured to receive and inject a flow of ambient or cool air is located in the lower end 220 of the drying chamber 200, while the first outlet 250 configured to exit a flow of heated humid air, is located in the upper end 210 of the drying chamber 200.

[0061] In preferred embodiments, one or more resistive electrical heating elements (not shown) are provided on the inner wall of the drying chamber 200. When required, such resistive electrical heating elements can be used for providing additional heating to the ambient or cool drying air, e.g. in instances when a reduced moisture content of the resulting dried kernels or grain is desired.

[0062] The source of infrasound 280, e.g. an infrasound generator, such as a pulsator, is operationally connected to the internal volume of the drying chamber 200, such as by tubings 283 and 285. The source of infrasound 280 is configured to produce an infrasonic sound wave in the flow of ambient or cool air in the drying chamber 200. The infrasonic sound wave should be controlled so as to cause desired displacement of kernels or grain on a tray 270 in the drying chamber. A suitable pulsator 280 can use a reciprocating piston or membrane to cause an oscillating or reciprocating air flow connected to the drying chamber 200 via tubings 283 and 285. While in principle one connection for infrasound could be used, it is presently preferred to use two connections at different locations on the drying chamber 200. While generally less preferred, the source of infrasound 280 could alternatively be located inside the drying chamber 200, or positioned in a wall thereof, such as in the case of a membrane.

[0063] The drying chamber 200 is preferably tubular, exhibiting a uniform cross section, e.g. circular or rectangular, along the length thereof in which the trays 270 are distributed. For an energy efficient heating in step B and heat-keeping in step C, the heat treatment chamber 100 of the inventive system 10 is preferably thermally insulated, so that loss of heat from the kernels or grain being conveyed in heat treatment chamber thereby is prevented, such as by loss of heat to the walls of the heat treatment chamber 100. By means of the thermal insulation, heating using merely the heating fluid is preferably enabled.

[0064] For an energy efficient drying and cooling, a drying chamber 200 of the inventive system is preferably thermally insulated, so that loss of heat from the kernels or grain being conveyed in heat drying chamber thereby is prevented, such as by loss of heat to the walls of the drying chamber 200.

[0065] A liquid application unit (not shown) may be included in the system 10 for contacting the heat treated kernels or grain having exited from the heat treatment chamber 100 with a cooling liquid before being entered into the drying chamber 200. The liquid application unit is provided with a means configured to finely divide the cooling liquid, e.g. a shower head, sprinkler head, or a nozzle.

[0066] The heat and moisture recovery unit 60 is preferably configured to continuously provide, via piping means 30, a flow of heated steam to be fed into first inlet 130 of the heat treatment chamber 100. Additionally, the heat and moisture recovery unit 60 is preferably configured to continuously receive, via piping means 20, a flow of heated humid air exiting from second outlet 160 of the heat treatment chamber 100. The heat and moisture recovery unit 60 could alternatively be configured to continuously provide, via piping means 30, a flow of heated humid air to be fed into first common inlet 130 of the heat treatment chamber 100 as shown in FIG. 1. The heat and moisture recovery unit 60 is also configured to continuously receive, via piping means 40, a flow of heated humid air exiting from first outlet 250 of the drying chamber 200, to dehumidify and cool said flow, and to provide a flow of dry and ambient or cool air to be fed, via piping means 50, into first inlet 230 of the drying chamber 200. The water absorbed during humidification in heat and moisture recovery unit 60 of is preferably used for providing heated steam, or moisture to the flow of heated humid air, being conveyed to the heat treatment chamber.

[0067] The heat and moisture recovery unit 60 preferably comprises a liquid desiccant (not shown), which is used for adsorbing moisture from a flow of heated humid air. A suitable air cooling and dehumidifying unit which can be used as the heat and moisture recovery unit 60 is available from Airwatergreen AB (SE), e.g. under the trade designation NEXT-S. The technology has been described in more detail in W02018009125A1.

[0068] The inventive system 10 allows for a reduced footprint of the heat treatment system as compared to traditional systems, especially in preferred embodiments wherein the drying chamber 200 of the system 10 comprises trays 270 and a source of infrasound 280. The latter embodiments of the inventive system 10 can be made more compact, less bulky, and volume demanding than most existing systems. Existing prior art systems have higher demands on the facility construction.

[0069] A conveyer 300, e.g. a belt conveyor, such as shown in FIG. 1, may be included in the inventive system 10 to transport heat treated kernels or grain from the heat treatment chamber 100 to a drying chamber 200.

[0070] Depending on the available height at the place of installation of the inventive system, the heat treatment chamber 100 could be arranged above the drying chamber 200, thereby allowing for gravitational transport of the heat treated kernels or grain from the heat treatment chamber 100 to a drying chamber 200.

[0071] When used for with plant-based kernels and plant-based grain for human nutrition purposes, the material of parts of the inventive system which said plant-based kernels and plant-based grain will be exposed to should be of food grade quality. As a suitable example, the heat treatment chamber 100, and, when included, also the drying chamber 200, can be made of stainless steel.

[0072] LIST OF REFERENCE NUMERALS USED

[0073] 10 system for treatment of kernels or grain

[0074] 20 piping means connecting second outlet 160 of heat treatment chamber 100 with heat and water recovery unit 60

[0075] 30 piping means connecting first inlet 130 of heat chamber 100 with heat and water recovery unit 60

[0076] 40 piping means connecting first outlet 250 of drying chamber 200 with heat and water recovery unit 60

[0077] 50 piping means connecting first inlet 230 of drying chamber 200 with heat and water recovery unit 60

[0078] 60 heat and water recovery unit

[0079] 100 heat treatment chamber

[0080] 105 feeding unit for feeding kernels or grain to the heat treatment chamber

[0081] 110 first, upper, end of heat treatment chamber

[0082] 120 second, lower, end of heat treatment chamber

[0083] 130 first inlet configured to receive and inject a heating fluid, optionally additionally configured to receive and inject a flow of heating air

[0084] 140 second inlet configured to receive kernels or grain

[0085] 150 first outlet configured to discharge heat treated kernels or grain from the heat treatment chamber

[0086] 160 second outlet configured to exit a flow of heated humid air from the heat treatment chamber

[0087] 170 perforated tray

[0088] 180 source of infrasound connected to heat treatment chamber

[0089] 183, 185 tubings connecting source of infrasound to heat treatment chamber

[0090] 190 inspection window

[0091] 200 drying chamber

[0092] 205 feeding unit for feeding kernels or grain to the drying chamber

[0093] 210 upper end of drying chamber

[0094] 220 lower end of drying chamber

[0095] 230 first inlet of drying chamber configured to receive dry air 240 second inlet of drying chamber configured to receive kernels or grain discharged from the heat treatment chamber 100

[0096] 250 first outlet configured to exiting a flow of heated humid air from the drying chamber 260 second outlet configured to discharge cooled kernels or grain from the drying chamber 200

[0097] 270 perforated tray

[0098] 280 source of infrasound connected to drying chamber

[0099] 283, 285 tubings connecting source of infrasound to drying chamber

[0100] 290 inspection window

[0101] 300 conveyor

Claims

CLAIMS1. A method of treating kernels or grain for use as food, foodstuff, feed, or seed, comprising the following steps:A a feeding step, wherein kernels or grain to be treated are fed to the method;B a heating step, wherein the kernels or grain are subjected to heat, so as to heat the kernels or grain to a desired temperature;C a heat-keeping step, wherein the heated kernels or grain from step B are kept in a heated state during a predetermined period of time;D a drying step, wherein the heat treated kernels or grain from step C are dried; and,E a discharging step, wherein the dried kernels or grain from step D are discharged from the method, characterized in that, in feeding step A, the kernels or grain are fed to a feeding end (110) of a heat treatment chamber (100); in heating step B, and in heat-keeping step C, the kernels or grain are kept on at least one perforated tray (170), arranged at a first level in height in the heat treatment chamber (100), said at least one perforated tray (170) being configured to be controllably positioned in either a grain holding position or in a grain passing position, are subjected to a humid heated atmosphere within the treatment chamber; in the heating step B and in the heat-keeping step C, the kernels or grain are advanced through the heat treatment chamber step-wise gravitationally towards a discharging end (120) of the heat treatment chamber; and, in that the kernels or grain in the heating step B and in the heat-keeping step C are subjected to infrasound.

2. The method of claim 1, additionally comprising regulating the residence time of the grain in each individual step in the heat treatment chamber (100) so as to correspond to a predetermined value.

3. The method of claim 1 or 2, wherein drying step D comprises subjecting the kernels or grain to a flow of cool and dry air while being conveyed along a path in an essentially opposite direction to the flow of cool dry air, thereby obtaining dried cool kernels or grain and a heated humid flow of air.

4. The method of claim 3, additionally comprising a heat and moisture recovery step F, wherein heat and moisture from the heated humid flow of air from the drying step D are recovered, and thereafter used in the heating step B and / or in the heat-keeping step C.

5. The method of claim 4, wherein, in the heat and moisture recovery step F, a flow of cool and dehumidified air is obtained, which flow is provided to the drying step D as the flow of cool dry air.

6. The method of any one of the claims 3-5, wherein, in heat and moisture recovery step F, heat and moisture from a heated humid flow of air from the heat treatment chamber 100 are recovered, and thereafter used in the heating step B and / or in the heat-keeping step C.

7. The method of any one of the preceding claims, additionally comprising a cooling step DCOOL preceding the drying step D comprising subjecting the kernels or grain to a cooling liquid, which is preferably water-based.

8. The method of claim 7, wherein the cooling liquid is water-based and contains a substance selected from the group consisting of: a growth stimulant, a disinfectant, H2O2, a microorganism, and sulphur.

9. A system (10) configured to treat kernels or grain for use as food, foodstuff, feed, or seed, the system comprising: a heat treatment chamber (100) having a first end (110) and a second end (120); and a feeding unit (105) configured to receive kernels or grain to be treated, and to feed to the treatment chamber (100) the kernels or grain to be treated; said heat treatment chamber comprising: a first inlet (130) configured to receive a heating fluid; a second inlet (140) configured to receive kernels or grain from the feeding unit (105); and, a first outlet (150) configured to discharge heat treated kernels or grain from the heat treatment chamber, said heat treatment chamber being configured to heat the kernels or grain using sensitive heat carried by the heating fluid being fed to the chamber by contacting the kernels or grain with the heating fluid, and to keep the kernels or grain heated for a predetermined period of time, characterized in that, the first end (110) is an upper end of the heat treatment chamber (100); the second end (120) is a lower end of the heat treatment chamber; the heating fluid is heated steam; the second inlet (140) configured to receive kernels or grain is located in the upper end (110) of the heat treatment chamber (100); the first outlet (150) configured to discharge heat treated kernels or grain from the heat treatment chamber is located in the lower end of the heat treatment chamber; the heat treatment chamber (100) additionally comprises at least one perforated tray (170), arranged at a first level in height in the heat treatment chamber (100), said at least one perforated tray (170) being configured to be controllably positioned in either a grain holding position or in a grain passing position; and, in that the heat treatment chamber (100) is connected to a source of infrasound (180) configured to produce an infrasonic sound wave in the heat treatment chamber (100).

10. The system (10) configured to treat kernels or grain of claim 9, additionally comprising: a drying chamber (200) configured to dry kernels or grain discharged from the heat treatment chamber (100), and a feeding unit (205) configured to receive kernels or graindischarged from the heat treatment chamber (100) and to feed to the drying chamber (200) kernels or grain to be dried.

11. The system (10) configured to treat kernels or grain of claim 10, wherein the drying chamber (200) comprises: an upper end (210); a lower end (220); a first inlet (230) configured to receive a flow of dry air; a second inlet (240) located in the upper end configured to receive kernels or grain from the feeding unit (205); a first outlet (250) configured to exiting heated humid air from the drying chamber; a second outlet (260) located in the lower end configured to discharge cooled kernels or grain from the drying chamber (200); and, at least one perforated tray (270), arranged at a first level in height in the drying chamber, and said at least one perforated tray being configured to be controllably positioned in either a grain holding position or in a grain passing position, and wherein the drying chamber (200) is connected to a source of infrasound (280) configured to produce an infrasonic sound wave in the drying chamber.

12. The system (10) configured to treat kernels or grain of claim 9 or 10, wherein the heat treatment chamber (100) additionally comprises: a second outlet (160) configured to exiting a flow of heated humid air from the heat treatment chamber (100); and a separate inlet configured to injecting a flow of air into the heat treatment chamber (100), or a combined first inlet (130), additionally configured to receive and enter into heat treatment chamber (100) a flow of heated air.

13. The system (10) configured to treat kernels or grain of claim 12, additionally comprising: a heat and water recovery unit (60) configured to recover heat and moisture from a flow of heated humid air exiting from the heat treatment chamber (100) via the second outlet (160), piping means (20, 30) connecting the heat treatment chamber with the heat and water recovery unit (60), said piping means (30) being configured to convey a flow of heated steamfrom the heat and water recovery unit (60) to the first inlet (130) configured to receive a heating fluid, and said piping means (20) being configured to convey a flow of heated humid air from the heat treatment chamber (100) exiting the second outlet (160) to the heat and water recovery unit (60).

14. The system (10) configured to treat kernels or grain of claims 9-12, additionally comprising: a heat and water recovery unit (60) configured to receive a flow of heated humid air exiting the drying chamber (200), and to produce a flow of dry air, and wherein the system additionally comprises piping means (40, 50) connecting the drying chamber with the heat and water recovery unit, said piping means (50) being configured to convey the flow of dry air from the heat and water recovery unit (60) to the first inlet (230) configured to receive dry air, and said piping means (40) being configured to convey the flow of heated humid air from the drying chamber via the first outlet (250) configured to the heat and water recovery unit (60).

15. The system (10) configured to treat kernels or grain of claim 12, additionally comprising: a heat and water recovery unit (60) configured to recover heat and moisture from a flow of heated humid air exiting from the heat treatment chamber (100) via the second outlet (160), piping means (20, 30) connecting the heat treatment chamber with the heat and water recovery unit (60), said piping means (30) being configured to convey a flow of heated steam from the heat and water recovery unit (60) to the first inlet (130) configured to receive a heating fluid, and said piping means (20) being configured to convey a flow of heated humid air from the heat treatment chamber (100) exiting the second outlet (160) to the heat and water recovery unit (60), and also configured to receive a flow of heated humid air exiting the drying chamber (200), and to produce a flow of dry air, and wherein the system additionally comprises piping means (40, 50) connecting the drying chamber (200) with the heat and water recovery unit, said piping means (50) being configured to convey the flow of dry air from the heat and water recovery unit (60) to the first inlet (230) configured to receive dryair, and said piping means (40) being configured to convey the flow of heated humid air from the drying chamber via the first outlet (250) to the heat and water recovery unit (60).

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