Patent Application
20210307367
The present invention relates to a line for heating, drying, cooking, disinfecting, pasteurizing and/or sterilizing a substance with an apparatus comprising at least one, preferably a multitude, solid-state radio frequency source(s) and a further heat treatment apparatus. The present invention further relates to a method for heating, drying, cooking, disinfecting, pasteurizing and/or sterilizing a substance with an apparatus comprising at least a solid-state RF energy source microwave heating step and a further heat treatment step.
Treating substances by passing microwave radiation through the substances is common as well as in domestic as in industrial applications. A conventional microwave oven for instance comprises a magnetron which produces the microwave energy. However, in industrial applications wherein microwaves are generated by a magnetron the long operating times will result in undesirable heat development and/or the process is not sufficiently reliable. Additionally, undesired hot spots may occur.
It is therefore the objective of the present invention to provide a processing apparatus and a method that do not comprise the deficiencies according to the state in the art.
The problem is attained with a line for heating, drying, cooking, disinfecting, pasteurizing and/or sterilizing a substance with an apparatus comprising at least one, preferably a multitude, solid-state radio frequency source(s) and a further heat treatment apparatus.
The disclosure made regarding this subject matter of the present invention also applies to the other invention and vice versa. Subject matters disclosed regarding this invention can also be combined with subject matters from other inventions of the present application.
The present invention relates to a processing line with a solid-state radio frequency (RF)-transistor(s) in a RF power amplifier. A radio frequency power amplifier is an electronic amplifier, that converts a low power radio frequency signal into a higher power signal. Typically, RF-power amplifiers drive the antenna of a transmitter. The antenna can be coupled to and/or located in a waveguide, wherein the antenna can radiate the microwaves into the waveguide which preferably is designed of reflective material and can guide the microwaves to a desired location, for example into the product chamber wherein the substances to be treated are located. Compared to a magnetron, an advantages of a solid-state RF energy technology is a low voltage drive, semiconductor reliability and lower energy consumption due to the advanced control system. The inventive apparatus can be used to for example heat, cook, dry disinfect, pasteurize and/or sterilize a substance.
The substance is preferably an edible substance for human- and/or animal-consumption, particularly protein containing food substance, particularly meat. The meat can be meat at a bone-structure, muscle meat and/or minced meat. In case the substance comprises a bone-structure, the bone structure is at least partially surrounded be the meat. A typical example for a substance with a bone structure is a chicken-wing, a chicken-leg, a leg from a pig or a lamb and/or fish. The substance can also be dough. The substance can also comprise at least parts of an insect or a mixture of insects. Those insects are preferably supplied alive to the inventive apparatus or line and are killed by microwave radiation. In another embodiment already killed insects will be preheated/precooked before the following processing step.
Transistor technology generates powerful RF fields. Preferably multiple RF sources will be applied, the sources can be controlled individually and preferably related to each other. For instance, in an application pumping a mass through a tube, gradually heating of the substance can be achieved by controlling the electromagnetic fields by controlling the power level, frequency and phase versus time with such precision that an even energy distribution will be achieved. In general, in case of a change in load in a certain spot of the substance, mass, substance flow or mass flow, the controller can control the specific parameters parameter in that certain spot in order to correct the adverse effects of the load change. For instance, during cooking the load will change constantly, this change in load will be detected via the antenna by measuring the reflected energy. The control system will compare the transmitted energy via the antenna with the reflected energy and will consequently adjust the energy to be transmitted by the antenna. For instance, if no load is present within the product chamber, no energy will be absorbed, the antenna receives the reflected energy and the control unit will stop transmitting new energy to the product chamber. With solid-state RF energy sources, the amplitude, the frequency, the phase versus time and/or the direction, and/or the total radiation energy emitted can be controlled for each and every antenna. Such an advanced energy management system based on a fast response to the heat demand in certain spots of the substance(s) to be heated prevents damaging of internal component and prevents an uncontrolled substance treatment with uneven energy distribution. Due to the efficient use of energy resulting in less energy loss an additional advantage of solid-state RF energy sources is an increase in yield of substances to be treated.
Additionally, according to the present invention, the line comprises a further heat treatment apparatus. In this heat treatment apparatus, the substance is preferably further cooked, browned, fried, smoked and/or roasted. The further heat treatment apparatus may be, relative to the flow of the substances, upstream or downstream from the solid-state radio frequency source(s)
A line according to the present invention comprises several treatment steps provided in a sequence. The substance is supplied to the line at its begin and is then transported continuously or semi-continuously through the line until the end of the line, where the substance is discharged and/or packaged. The transportation can be done by means of a conveyor, for example a belt, which connects the apparatus. Preferably, the line comprises a common control unit, which controls the individual apparatus as well as the handover of the substances from one apparatus/step to the other.
According to a preferred embodiment of the present invention, the apparatus may not only comprise one but a multitude of solid-state radio frequency sources. This can be accomplished by using one or more antennas and/or one or more waveguides. Each radio frequency source can be preferably powered individually and each radio frequency source can be preferably controlled, more preferably closed loop controlled, individually. The frequency, the wavelength, the phase versus time, the amplitude, the direction of radiation and/or the overall magnitude of the radiated power can be controlled.
The solid-state radio frequency sources are preferably provided in an array of n columns and m rows, wherein n is an integer >1 and m is an integer ≥1. Preferably, the solid-state radio frequencies are arranged equidistantly in one row and/or the columns are also arranged equidistantly. In case a multitude of sources, they can be arranged at random.
Preferably, the solid-state radio frequency sources are provided equidistantly around the circumference of product chamber. In this chamber, the edible substance to be treated will be placed or it will be transported through this product chamber.
According to a preferred embodiment, each apparatus in the line comprises an inlet and an outlet, which are spaced apart from each other. The, preferably edible, substance enters each apparatus through the inlet, passes through the apparatus and then exits the apparatus through the exit which is preferably different from the inlet.
Preferably, each apparatus comprises means to transport the substance past the treatment means of the apparatus, for example the solid-state radio frequency source(s). These means can be a tube and a pump, which pumps the substance through the tube. The tube is in the present case the product chamber. Preferably, the tube is at least partially made from a material, that is at least partially transmittable, preferably transparent for the RF-radiation. The tube can for example be made from a plastic material, preferably from a food grade plastic material. The pump pumps the substance preferably as a continuous or semi-continuous stream past the RF-source(s). The speed at which the substance is pumped is preferably adjustable, so that the residence time in the product chamber can be varied. The means can also be a conveyor, for example a belt, preferably an endless belt or an endless chain, wherein the chain is preferably not made from a metal material. The conveyor is preferably at least partially transmittable for the RF-radiation. This conveyor transports the edible substance, preferably as individual portions, past the solid-state radio frequency source(s). The substances are preferably transported continuously or intermittently by the conveyor. The speed of the conveyor is preferably adjustable, so that the residence time in the product chamber can be varied. Each apparatus of the line may have its own conveyor means, particularly conveyor belt, which transports the substances through the respective apparatus.
At least some of the conveyors, preferably each conveyor, is adapted to the specific requirements in the respective apparatus. The products are preferably handed over from one conveyor to the other. At least one of the conveyors may comprise means to distribute and/or accumulate the products on the respective conveyor and more preferably according to the needs of the specific treatment step.
Preferably, each processing apparatus and/or the line comprises a control system to control the individual apparatus, for example the solid-state radio frequency source(s) and/or the transportation means. The control system preferably comprises one or more sensors, whose signal(s) is used to control the parameters of one or more apparatus in order to achieve desired treatment of the substance. Preferably, each apparatus is controlled individually, but preferably by a common line control system. Preferably one or more sensors are utilized to control one or more solid-state radio frequency source(s), preferably individually and/or related to each other. For instance, in an application pumping a mass through a tube, gradually heating of the mass can be achieved by controlling the electromagnetic fields by controlling the power level, frequency and/or phase versus time with such precision that, for example, an even energy distribution in the product chamber or in the substance will be achieved. The RF-energy load can be adapted to the progress of the treatment process. For instance, during cooking the RF-energy load can change. This change in load can be detected, for example via the antenna by measuring the reflected energy. The control system will compare the transmitted energy via the antenna with the reflected energy and will consequently adjust the energy to be transmitted by the antenna. At each solid-state RF energy sources, the amplitude, the frequency, the wavelength, the phase versus time, and/or direction of radiation can be controlled individually and/or in groups. The antenna may function as a sensor, for example to detect the radiation reflected from the substance to be treated.
The control system preferably controls at least one solid-state radio frequency source such that it specifically heats the bone structure, in order to specifically heat the meat surrounding the bone so that it reaches a temperature of at least 80° C., preferably at least 84° C. This preferred embodiment is particularly preferable in case the, solid-state radio frequency source(s) is used as a post heating step.
The sensor can sense one or more properties of the substance, for example its temperature and/or the energy absorbed by the substance or part of the substance, for example a bone-structure and/or the meat surrounding a bone structure. One sensor can measure what kind of radiation is reflected from the substance, for example the wavelength. The sensor can measure a temperature inside the substance, preferably the core temperature and/or a temperature distribution within the substance. In case the substance is transported during its treatment, particularly with the RF-radiation, there can be multiple sensors along the transportation path. The local reading of the sensors can be used to control the corresponding local treatment apparatus, for example the solid-state radio frequency source(s) and/or the solid-state radio frequency source(s) upstream and/or downstream from the respective sensor.
The inventive food production line, preferably also comprises one or more treatment apparatus upstream and/or downstream from the apparatus with the solid-state radio frequency source(s), which change the consistency, the shape and/or the surface of the substance, for example a cutting-, grinding-, injection-, marinating-station, a forming station, a batter-station and/or a marination-station. The stations can be combined with conveyors. Preferably the substance enters the line at its entrance and then passes successively all stations of the respective line until it finally exits the line.
Preferably, the inventive line is provided downstream from a hopper in which, for example, a batch of an edible material is stored.
Preferably, one or more apparatus in the line, particularly the apparatus with the solid-state radio frequency source(s), can be at least partially isolated from the ambient by one or more valves/gates. The substance, preferably the edible product, enters the respective apparatus, for example by means of a conveyor. Then the conveyor is stopped and a valve, like a gate is closed, preferably at the entrance and at the exit of the conveyor, so that, for example, no or little radiation can exit from the apparatus to the ambient. After the RF-treatment, the valve/gate is reopened again and the treated substance can exit the apparatus and preferably simultaneously untreated substance enters the apparatus. The valve/gate can also be a feedthrough, particularly a rotary feedthrough, so that a continuous or semi-continuous substance flow can be achieved.
Line according to the present invention preferably comprises:
According to a preferred embodiment of the present invention, the solid-state RF energy source(s) and the convection cooking means are provided in one housing, preferably connected by conveyor means. The conveyor means are preferably adapted to the needs during the solid-state RF energy source microwave treatment step and the convection cooking step. Alternatively, two successive conveyors are provided, each adapted to the specific need of the solid-state RF energy source microwave treatment step and the convection cooking step.
Preferably, the line comprises means to measure the doneness of the substance. The doneness can, for example be determined by a temperature at the core of the substance, at a bone-structure within the substance and/or by determining a temperature distribution within the substance. The doneness can be determined for each substance or at random. Preferably, the measurement of the doneness is executed with the solid-state RF energy source(s). The RF energy source(s) are preferably controlled based on such a measurement, for example to specifically heat the at the core of the substance and/or at a bone-structure within the substance. In this case it is preferred that the RF energy source(s) is provided downstream form a conventional heating step such as frying, roasting, browning or cooking.
Preferably, the substance comprises a bone-structure, wherein at least one solid-state radio frequency source is controlled to specifically heat the bone-structure and/or the meat surrounding the bone-structure. This can be for example carried out by controlling the frequency, the wavelength, the phase versus time, the amplitude, the direction of radiation
and/or the overall magnitude of the radiated power of at least one RF energy source such the specifically the bone structure and/or the meat surrounding the bone structure are heated, so that their temperature is increased fast, while preferably the other meat of the substance is heated less.
The problem is also solved with a method for heating, drying, cooking, disinfecting, pasteurizing and/or sterilizing a substance with an apparatus comprising at least a solid-state RF energy source microwave heating step and a further heat treatment step.
The disclosure made regarding this subject matter of the present invention also applies to the other invention and vice versa. Subject matters disclosed regarding this invention can also be combined with subject matters from other inventions of the present application.
The problem is furthermore solved with a method for heating, drying, cooking, disinfecting, pasteurizing and/or sterilizing a substance with an apparatus comprising a heat treatment step and a post heating with at least a solid-state RF energy source microwave heating step.
The disclosure made regarding this subject matter of the present invention also applies to the other invention and vice versa. Subject matters disclosed regarding this invention can also be combined with subject matters from other inventions of the present application.
The following disclosure applies to both inventive methods.
The substance to be treated can be an edible substance, for example meat, fish or dough. The fish and the meat may comprise a bone-structure. The substance can also be an insect, which is, for example, killed by the RF-radiation. In another embodiment already killed insects will be preheated/precooked before the following processing step.
Preferably the substance is transported from an inlet of a treatment apparatus to an exit of the same apparatus which are spaced apart.
The substance can be transported continuously and/or intermittently. They can be transported as a string as an array or as individual portions.
Preferably one or more sensors are provided which measure one or more properties of the edible substance and/or the radiation reflected from the substance. The substance-properties are preferably measured at least twice during its treatment, preferably during its treatment with RF-radiation. The changes of the properties are determined and can be taken into account when controlling the solid-state radio frequency source(s) and/or another apparatus in the line.
Preferably, the substance is heated, cooked, dried, disinfected and/or pasteurized, sterilized, fried, roasted, browned smoked and/or grilled.
At least one parameters of the substance to be treated are inputted into a control system and that a control unit sets the parameters at least for the solid-state RF energy source microwave heating step accordingly. One example of a parameter is for example whether the substance comprises a bone-structure and/or the size, preferably the average size of the bone-structure, or the volume of the bone structure, preferably versus the volume of the surrounding meat.
Preferably, the substance comprises a bone-structure, wherein the post heating, i.e. the heating after a preheating step is adapted to specifically heat the bone-structure. Preferably, the post heating is carried out with RF-radiation and at least one solid-state RF energy source is controlled to specifically heat the bone structure or the meat surrounding the bone structure. This can be carried out by controlling the frequency, the wavelength, the phase versus time, the amplitude, the direction of radiation and/or the overall magnitude of the radiated power to specifically heat the bone-structure and/or the surrounding meat.
Preferably, at least one solid-state radio frequency source is utilized to measure the doneness of the substance.
Preferably, the parameters of the further heat treatment step or the post heating step are controlled by the control unit.
The problem is also solved with a method of treating a substance containing a bone structure, wherein the bone marrow is heated with microwaves generated by solid-state RF energy sources.
The disclosure made regarding this subject matter of the present invention also applies to the other invention and vice versa. Subject matters disclosed regarding this invention can also be combined with subject matters from other inventions of the present application.
The following disclosure applies specifically to both inventive methods and the inventive lines.
As an example, the chickens we consume today are between six and eight weeks old and have under developed more porous bones than older chickens. When young chickens/broilers are frozen, liquids in the mass of chicken including bone marrow will expand. The bone marrow inside of chicken bones is purplish and can permeate through the porous chicken bones as it expands and forms ice crystals. These ice crystals further break down the bone structure. In case of heating products with bones such as chicken drumsticks, for instance after coating these products, the purple marrow in the bones seep through the porous bones and leaks into the meat. The surface of the bones and the adjacent meat become deep red/purple or even black which is visible and unattractive. First cooking and then coat the food product with for instance batter results also in leakage of bone marrow however the coating camouflages this.
Surprisingly, it has been found, that the leakage of bone marrow can be reduced or preferably stopped by coagulate the marrow within the bones by using microwaves generated by solid-state RF energy sources. The settings such as power level, frequency, wavelength, phase versus time, amplitude, magnitude of radiated power and/or direction of radiation will be optimized to penetrate the chicken meat, bone structure and to treat bone marrow. The treatment of substances comprising a bone-structure with microwaves will be applied before the substances are subjected to a heat treatment process such as frying and cooking, preferably the treatment will be applied before the fresh chicken bone-structure containing substances will be frozen. The process to minimize/stop leakage of marrow is not limited to chicken bone-structure comprising substances but is also applicable for other bone-structure containing substances such as beef, lamb, pork, poultry in general.
Preferably the microwave heating is carried out prior to a heat treatment of the substance, preferably in an oven or a fryer, or prior to freezing of the substance.
The inventions are now explained according to the Figures. The explanations apply for all embodiments of the present invention likewise.
The inventions are now explained according to
The number of solid-state elements 2/antennas 17 preferably depends on, for instance, the required heating power, the width of the belt, the length of the housing, the number and/or size and/or consistency of substances 11, the position of the substances on the belt, the speed of the belt and/or the desired accuracy and/or speed of the heat treatment process, particularly the uniformity of the heating process.
Regarding the embodiment of
Regarding the embodiment according to
Regarding the embodiment according to
In applications depicted in
In an embodiment of the invention the temperature of food substances 11 spread across the width of the conveyor means 10 is measured and in case of deviating temperatures of the substances, the difference will at least partially be equalized. Reference can be made to
In a preferred embodiment of the invention a heat treatment line comprises a multitude of heat treatment apparatus including at least one microwave heating apparatus, wherein the microwaves are generated by solid-state RF energy sources. Other apparatus in this heat treatment line are for instance a deep fat fryer, a convection cooking heating apparatus and/or a steaming apparatus. For example, precooking takes place in a linear microwave oven and final cooking takes place in a single spiral oven.
In another embodiment, the function of multiple separate heating apparatus will be combined in one or more heating apparatus. For instance, a single heat treatment apparatus is provided with microwave heating means generated by solid-state RF energy sources in one zone and convection heating means in one or more other zones.
In a further embodiment solid-state RF energy sources to generate microwave heating will be provided within one or more cooking chambers/zones combined with one or more other heating means. Aim of this inventive application is to end up with the desired texture, taste/bite, moisture content, appearance and color of the resulting substance in a relatively short period of time by a combination of simultaneously running heat treatment processes in one and the same cooking chamber/zone such as a combination of microwave heating generated by solid-state RF energy sources and convection heating. In case multiple climate zones are needed, the oven will be provided with multiple cooking chambers/climate zones and each and every chamber/zone can be provided with multiple heating means resulting in an extension of the scope of substance and process applications.
Preferably, the processing apparatus and/or the inventive line comprises a control system to control the solid-state radio frequency sources. The control system preferably comprises one or more sensing means, whose signal(s) is used to control one or more solid-state radio frequency source(s), preferably individually and/or related to each other. For instance, in an application transporting substances over a continuous running belt, gradually heating of the substances can be achieved by controlling the electromagnetic fields by controlling the frequency, the wavelength, the phase versus time, the amplitude, the direction of radiation and/or the overall magnitude of the radiated power. The phase of the signal from one or more solid-state RF energy sources can be shifted relative to the others which will change the energy distribution within the cooking chamber. This with such precision that, for example, an even energy distribution in the product chamber or in the substance will be achieved. Other parameters influencing the heat treatment of food substances are type of food, weight, temperature, moisture content and parameters related to the processing apparatus such as heating power. During heat treatment of food substances parameters such as temperature and moisture content will change and therefore multiple measurements should be done in the course of the process. Consequently, the control unit will take these measurements into account when controlling the solid-state radio frequency sources. The closed-loop control system will use the feedback information of the sensing means to select the timing or the heat sources, the power of the heat sources and the climate in the oven such that the cooking of the substances will be optimized.
In a preferred embodiment of the invention the solid-state RF energy load can be adapted to the progress of the treatment process. For instance, during cooking the solid-state RF energy load can change. This change in load can be detected, for example via the antenna 17 by measuring the reflected energy. The control system will compare the transmitted energy via the antenna with the reflected energy and will consequently adjust the energy to be transmitted by the antenna. At each solid-state RF energy source, the frequency, the wavelength, the phase versus time, the amplitude, the direction of radiation
and/or the overall magnitude of the radiated power can be controlled individually and/or in groups. The antenna may function as a sensor, for example to detect the radiation reflected from the substance to be treated. With this information the control unit can determine to which spots in the substance more or less energy should be radiate such that, in case of preheating/precooking food substances, within certain tolerances, an equal temperature of all substances can be achieved by adjusting the signals to each solid-state RF energy source. In this way cold spots and hot spots in the food substance, typical to an oven wherein microwaves are generated by a magnetron, will be avoided. Multiple antennas can be provided in order to increase the effectiveness of the control system and the antennas can be positioned in different planes and/or positions along the movement path of the food substances.
In a further embodiment of the invention the energy absorbed by the substance can be measured (absorption measurement) and via an algorithm can be detected what the doneness of the food substance is, in what stage the cooking process is and this will be the base to determine to finish the cooking process to reduce/prevent cooking losses and to prevent that the food substances will be overcooked.
In one embodiment detection means 25 such as a camera can be provided to be able to detect/identify the position and/or type and/or volume and/or color of the food substance/mass. Therefor the detection means is preferably positioned at the entrance of the apparatus. Further downstream in the apparatus detection means can be provided to detect/identify the status of the heating process and as a result of the images the control unit can adjust the heating process. More preferably the detection means and relating software will be used able to handle conveyor means with multiple lines with substances but also be able to handle conveyor means with random oriented food substances. The control unit is able to determine at which time which energy source will be activated based on amongst others the speed of the conveyor 10. In case for instance the volume and type of the food substances is determined the control unit is able to calculate the heat treatment process parameters.
For all above mentioned embodiments, a control system can be provided to be able to introduce pre-programmed cooking menus/recipes. Basic parameters for the menus/recipes are for instance belt load and/or speed of the conveyor means. Input parameters in the cooking menu/recipe based on cooking with microwaves are for instance temperature of the substance, size of the food substance, weight substance, moisture content substance and food type. With the set of parameters, the control unit can determine the cooking parameters such as temperature and time and is able to (pre)heat/((pre)cook the food substances. However, manually input of these cooking parameters will also be possible and within certain ranges the control can optimize the manual inputted values depending on the substance parameters and the running cooking process.
In case of a combination oven input parameters will also be related to other heat sources. For instance in a combination oven comprising solid-state RF energy sources and convection cooking means, input parameters such as temperature hot air, humidity, fan speed, flowrate process fluid, time and pressure can also be part of the cooking menu.
Final cooking of food substances with only microwaves can result in an undesired texture, taste/bite, moisture content, appearance and color. In a first embodiment of the invention use is made of the advantages of microwaves combined with the advantages of heat treatment processes such as frying and/or cooking. The food substance such as meat and fish will be preheated/precooked with microwaves before the next heat treatment processing step such as frying and/or cooking.
In
This modular design results in reduction of costs and an increased flexibility regarding process applications.
In this embodiment formed meat substances such as burgers, nuggets, chicken wings or a food mass will be heated. Shielding means 24 can positioned at the inlet of module M1 and/or at the outlet of module M6 to prevent microwaves from coming out of the apparatus. Module M1 is here provided with sensor means in order to determine the presence of substances on the conveyor 10. This information can be used in module M2 to determine when the heating process should be started. Both modules M2 and M3 hear comprise solid-state RF energy sources. In module M4 absorption measurements can be done to determine if the meat substances are equal heated. In module M5 further heating will be provided to the substances but preferably only were need according the measurements in module M4; i.e. substances are individually whose temperature is too low. Module M6 can, for example, be provided with infrared heating means, particularly for boneless and flat shaped products, in order to establish browning and/or a crispy outer layer. In a more preferred embodiment the sensing means in M1 can determine the dimensions, shape and/or volume and/or weight of the food substance. This data can be utilized in a control unit to calculate and control an individual heating process for each and every single food substance on belt 10 or for a row and/or column of substances on the belt.
The modules M1-M6 are preferably provided on a frame 27, more preferably on the frame of the conveyor means 10. Preferably, the sequence of the modules M1-M6 can be changed. Each module M1-M6 and the conveyor means are preferably connected to the same control system.
The conveyor means 10, are preferably designed such that they are at least partially, preferably entirely transparent for the microwave radiation.
In
In case the processes in all modules are finished the respective shielding means can be altered, for example tilted such that the substances can move from one module to another. As soon as the substances are shifted to the next module, shielding means can close again.
Regarding
Reference is particularly made to the embodiments according to
Via the antenna 17 microwaves are radiate to the substances to be heated and ingredients such as water and fat will absorb the energy. Simultaneously that part of radiation what is not absorbed by the ingredients in the substance will be absorbed by the antenna and the measured absorption will be used to control the solid-state RF energy sources.
Depending on the width of the belt and the number of substances positioned on the belt two or more solid-state elements and antennas will be used in order to increase accuracy of the process.
Reference is particularly made to the embodiments according to
By pre-heating food substances with microwaves generated by solid-state energy sources the entire substance volume will be, within certain tolerances, heated at once and hot- and/or cold-spots can be avoided due to control of radiation based on absorption measurement. All substances along the width of the conveyor means have at least essentially the same temperature.
Result will be that the fryer or cooking oven can run with a higher line speed (less residence time substance in fryer or oven) or less heating capacity in the fryer or oven is needed resulting in energy-saving.
This is a typical line application in which the inventive apparatus is combined with another apparatus, for example a fryer and/or a cooking oven. The solid state RF energy source can be provided up- and/or downstream from the other apparatus in the line.
Reference is particularly made to the embodiments according to
In above embodiments microwaves generated by solid-state RF energy sources are deployed to preheat, precook and/or dry food and feed substances before these substances are subjected to a next or final heat treatment step within a further processing line.
In different, following embodiments microwaves generated by solid-state RF energy sources will be deployed after a previous heating, cooking and/or drying treatment. However, for the following examples, reference is also made to the explanations according to
In case of a coated substance during par-frying the core of the substance will remain unaffected e.g. un- or only little heated and/or no or little oil-absorption. Due to dehydration of the surface the Maillard reaction creates a golden brown exterior of the food substance. This dehydration will settle the coating; it forms a, preferably crispy, crust, an essentially closed layer which prevents or limits oil absorption and prevents loss of moisture/natural juices further downstream.
A par-fried food substance is not fully cooked and will be directly frozen after frying or the whole substance be fully cooked in a line or spiral oven or in this embodiment by microwaves generated by solid-state RF energy sources.
In case of steam cooking, e.g. condensation cooking of uncoated food substances, such as fillets, the substances can be treated with microwaves generated by solid-state RF energy sources either before or after the steam cooking process. The combination of both processes will have the benefits of steam cooking (retaining of nutrients without dried out food substances) and microwave, which can a fast process.
In
In case of cooking substances comprising a bone structure in an oven the meat is relatively quickly cooked and colored, preferably with hot air with a predetermined humidity via the outside of the product, however the bone itself is not heated or not sufficiently heated. Due to safety reasons (reduction of bacteria to a safe level) the bone temperature needs to be above a minimum temperature, for instance 84° C., much higher than the core temperature of the meat should be. In traditional cooking applications the cooking process will be proceeded until the bone temperature has reached the desired correct temperature. However, the substances remain a relatively long period within the cooking oven which results in cooking losses such as the loss of water, other juices, fat and salts.
In the examples according to
In an embodiment of the process cooked substances will exit the oven at a temperature below the desired meat temperature and/or below the desired bone-structure-temperature. In the next processing step microwaves generated by solid-state RF energy sources can be applied to further heat the meat and bone structure for instance from 65° C. to 84° C. Preferably the meat temperature (core temperature) will be heated from 65° C. to the desired temperature, for instance 72° C. and preferably the bone structure will be heated to the desired temperature, for instance 84° C.
In another embodiment of the process the substances will exit the oven with the desired meat temperature, for instance 72° C. and in the next processing step microwaves generated by solid-state RF energy sources can be applied to further heat the bone structure till the desired temperature, for instance 84° C. The food substances are subjected to a relatively short cooking time in the oven.
Simultaneously or in a next processing step the solid-state energy sources can be applied to measure the temperature of the meat and/or bone-structure of the multiple food substances for example on a conveyor and in case the meat temperature or the temperature of the bone structure of the preferably individual food substances is not according the desired temperature further heating of the meat and/or bone structure of the preferably individual food substances will be applied. Correcting the temperature of a meat substance with microwaves after the cooking oven gives the opportunity to heat the food substance within the oven just until the desired temperature which results in less cooking losses and increased energy efficiency.
Preferably, at least one solid state RF energy source will be controlled such, that it specifically heats the bone structure and/or its surrounding meat. The frequency, the amplitude, the frequency, the wavelength, the phase versus time and/or direction of radiation
and/or the radiation energy emitted by the solid state RF energy source can be controlled such that the microwaves is specifically absorbed by the bone and/or the surrounding meat, particularly the meat that has not yet reached the desired temperature. The temperature of the bone and/or the surrounding meat is preferably monitored and the emission of the solid state RF energy source is preferably adapted.
In
Besides preheating, precooking, drying, post-heating and post-cooking microwaves generated by solid-state RF energy sources can also be applied further upstream, preferably before the substances entering a further processing line or at least before the substances will be subjected to heat treatment within the further processing line. Aim is to heat the bone structure and/or, depending on the application, combined with limit heating of the meat.
In a traditional process of processing substances comprising a bone-structure, for instance coated drumsticks or coated chicken wings, first the coating will be applied, then the substance will be par-fried such that the coating will be settled and in a next step the substance will be finally cooked in an oven. However, when dealing in particular with frozen young chickens/broilers the surface of the bone and adjacent muscle tissues can become colored after cooking due to leakage of bone marrow.
The chickens we eat today are between six and eight weeks old and have under developed more porous bones than older chickens. When young chickens/broilers are frozen liquids in the mass of chicken including bone marrow will expand. The bone marrow inside of chicken bones is purplish and can permeate through the porous chicken bones as it expands and forms ice crystals. These ice crystals further break down the bone structure. When heating/cooking the purple marrow in the bones seep through the porous bones and leaks into the meat. The surface of the bones and the adjacent meat become deep red/purple or even black.
In an embodiment of the invention the leakage of bone marrow can be stopped by coagulate the marrow within the bones by using microwaves generated by solid-state RF energy sources. The temperature will preferably be in the range of 50° C. till 80° C., more preferably 50° C. till 70° C. The settings such as power level, frequency, wavelength, phase versus time, amplitude, magnitude of radiated power and/or direction of radiation will be optimized to penetrate the chicken meat, bone structure and to treat bone marrow. The treatment of substances comprising a bone-structure with microwaves will be applied before the substances are subjected to a heat treatment process such as frying and cooking, preferably the treatment will be applied before the fresh chicken bone-structure containing substances will be frozen. The process to minimize/stop leakage of marrow is not limited to chicken bone-structure comprising substances but is also applicable for other bone-structure containing substances such as beef, lamb, pork, poultry in general. The status of coagulation of proteins and starch will be determined by absorption measurements with solid-state RF energy sources. The status can be determined by comparing the measured results with the known and in the control system implemented absorption curve of both non-coagulated proteins and starch and entirely coagulated proteins and starch.
Particularly regarding
This problem is solved with the embodiment according to
Regarding
Field experience learns that oil content in the currently available coatings is often critical low. To improve this more oil should be supplied to the food product.
Solid-state RF energy sources to generate microwaves are implemented in the embodiment of
In
This embodiment is not limited to non-coated food products but is also applicable for all kind of coated products.
Regarding
At a certain moment, when wet bulb temperature is reached, the rise of temperature stops/stalls despite supplying energy to the meat products. This temperature stall is the point when the product temperature has reached the wet bulb temperature and is caused by evaporative cooling. The time period of the stall is determined by the free moisture from the meat and from the marinade in case the product is marinated. This free moisture is evaporating from the pores and cells and consequently cools down the meat. As the temperature of cold meat rises, the evaporation rate increases unit the cooling effect balances the heat input. The stall stops when “unbound free water” from the surface and just below is released.
The cooking process will be continued in the oven in preferably an impingement zone with high air temperature directed with high speed to the surface of the product succeeded by a convection zone with increased temperature to for instance brown the products. During cooking both the surface and core temperature will follow a line. During the stall this line slopes down and after the stall the line follows the original curve. The thermal conductivity of the food product determines how quickly the temperature difference between surface and core can be reduced, this parameter cannot be changed.
Regarding
Less free water will decrease the period of the evaporative cooling and a shorter period of stall thereby increasing the (energy) efficiency of the cooking process.
In another embodiment of the invention depicted by
Solid-state RF energy sources will be positioned within the oven to be able to direct microwaves to the food products. These energy sources can be positioned just after the products enter the oven to be able to increase the surface temperature and/or the core temperature at an early stage, and/or somewhat further in the oven to boost mainly the core temperature of the food products.
In a different embodiment these energy sources will be positioned, preferably alternatively or additionally, just after the location in the oven where the stall is reached. Microwaves will then increase the core temperature of the product.
In a further embodiment energy sources will be positioned, preferably alternatively or additionally, in for instance in the second and/or third zone. Multiple solid-state RF energy sources can be positioned in different locations within the oven to be used for different tasks and/or combinations of tasks. Applying microwaves directed by solid-state RF energy sources will shorten cooking time and/or increase the oven capacity.
In a further embodiment condensation cooking respectively convection cooking will be applied to heat the food product from the outside to the inside and will be combined with microwaves generated by solid-state RF energy sources mainly to boost the core of the food product.
The described use of solid-state RF energy sources is also applicable to a spiral oven consisting of one zone and a linear oven consisting of one or multiple zones.
For all applications described in this document the combination of multiple frequencies can be applied. For instance a low frequency of approximately 915 MHz for heating up thicker blocks of food mass between surface and core of the product and a higher frequency to direct heat only to the outside surface of the food product. Multiple frequencies can be generated by one solid-state RF energy source but preferably generated by multiple solid-state RF energy sources wherein each and every solid-state energy source will generate a certain programmed frequency. Preferably solid-state RF energy sources generating different frequencies are within the heating apparatus located in different product chambers.
A step with a higher frequency than 2450 MHz generated with solid-state RF energy sources, preferably between 3 GHz and 300 GHz, can be directed to the outside of the product. Less penetration depth will only dehydrate the surface of the food product to create a Maillard reaction resulting in a golden brown exterior of the food substance. Preferably the browning will take place over the entire surface area of the product, therefor one or more energy sources will be used. The control unit will adjust the phase change in order to achieve a controlled browning around the entire surface.
For instance a bone-in product as drumsticks can be treated with a frequency of 2450 MHz to heat up the product between the surface and core of the product and a higher frequency only directed to the surface of the product in order to create a Maillard reaction.
The processes described above are not limited to meat substances but are also applicable for fish, vegetarian substances, vegetables, pet food, etcetera.
The processes described above are not limited to a process step with microwaves generated by solid-state RF energy sources before a fryer and/or cooking oven or a process step with microwaves generated by solid-state RF energy sources after a fryer and/or cooking oven. The combination of a process step with microwaves generated by solid-state RF energy sources before and after a fryer and/or cooking oven and/or another heat treatment process is also applicable.
The use of measurement means and/or the combination of measurement means such as absorption measurement by solid-state sources, doneness measurement by using solid-state sources and detection means 25 such as cameras are not limited to one of the Figures above.
For all embodiments and all examples provided above measuring/detection means 25, such as cameras, can be provided to be able to detect/identify the position and/or type and/or shape and/or weight and/or volume and/or density and/or dimensions and/or color of the food product/mass.
Measuring/detection means such as cameras can be provided in order to detect/identify the belt load and the position and variation of products/mass.
Measuring/detection means such as thermal imaging cameras can be used in order to control the temperature within the process. These measurements are non-contact temperature measurements and can be used to measure the doneness/if food products are well cooked as well as in an oven as in the microwave.
The measuring/detection means such as cameras can be positioned before/at the entrance of a heat treatment process such as an oven in order to be able to adjust the parameters of the cooking process, the cameras can be positioned further downstream for instance in an oven to detect/identify the status of the process and successively the information can be used by the control unit to adjust relative parameters. The measuring/detection means can be positioned after the for instance heat treatment process in order to check if the products are well cooked. In a preferred embodiment the measuring/detection means such as cameras will be able to detect/identify relevant parameters of each and every food product such that particularly when using solid-state RF energy sources each and every food product can be treated separately. In case for instance the volume and type of the food substances is determined the control unit is able to calculate the heat treatment process parameters.
The measuring/detection means such as cameras will be used able to handle conveyor means with multiple lines with substances but also be able to handle conveyor means with random oriented food substances. When using solid-state RF energy sources the control unit is able to determine at which time which energy source will be activated based on amongst others the speed of the conveyor.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18174306.3 | May 2018 | EP | regional |
| 18195724.2 | Sep 2018 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/063616 | 5/27/2019 | WO | 00 |
