WO2023007522A1

WO2023007522A1 - Low temperature cooking method and apparatus

Info

Publication number: WO2023007522A1
Application number: PCT/IT2022/050217
Authority: WO
Inventors: Alessandro Benedetti; Fabio BISETTO; Manuel ZANETTE
Original assignee: De' Longhi Appliances S.R.L. Con Unico Socio
Priority date: 2021-07-27
Filing date: 2022-07-26
Publication date: 2023-02-02
Also published as: AU2022320060A1; EP4376683A1; IT202100020051A1; CN115670222A

Abstract

A method to cook foodstuff (100) at low temperature in an apparatus (10; 110) comprising a plate cooking device (11) with a lower plate (12) and an upper plate (13) opposite and facing each other and associated with heating elements (14, 15), provides to dispose the foodstuff (100) between the two plates (12, 13) contained in a space (S) delimited by a containing element (16; 116; 216; 50). The method also provides to keep the temperature and moisture inside the delimited space (S) controlled, and cook the foodstuff (100) at low temperature reducing to a minimum a time interval in which the foodstuff (100) remains within a temperature zone at risk of bacterial proliferation.

Description

“LOW TEMPERATURE COOKING METHOD AND APPARATUS”

FIELD OF THE INVENTION

The present invention concerns a method and a corresponding apparatus suitable to cook foodstuff at low temperature, in such a way as to preserve its organoleptic characteristics.

BACKGROUND OF THE INVENTION

It is known to cook foodstuff at a low temperature to impart or maintain softness and juiciness.

Normally this type of cooking is carried out in immersion, closing the product to be cooked inside a waterproof plastic bag, even in a vacuum, and placing it inside containers containing water that is maintained at a defined temperature by a thermostat.

The cooking method that combines the use of low temperature with vacuum is generally defined as the sous-vide method and normally requires very long cooking times, even lasting a few hours, depending on the size and type of product to be cooked.

Although it guarantees excellent results in terms of quality, softness and maintenance of the organoleptic properties of the cooked foodstuff, this cooking method requires to use volumes of water heated for a long time and to have both suitable tools to obtain the vacuum and also tools to guarantee the correct control of the temperature and/or water level.

Low temperature cooking can also be performed inside an electric oven, for example a hot air oven, with the help of a source of steam. In this way, however, the final quality of the product is lower than that obtainable from immersion cooking.

If the electric oven is a hot air oven, it must be equipped with adequate instruments to maintain the desired cooking conditions.

In general, in low-temperature cooking processes it is necessary to precisely control the temperature to limit to a minimum the time in which the products remain inside a certain temperature range, normally comprised between 10°C - 55°C, with a greater risk of bacterial proliferation, so as to guarantee the safety of the cooking process and therefore the health of a consumer. In addition, with low temperature cooking solutions, to regenerate or finish the product in order to brown it, it is necessary to use additional appliances, such as for example a grill, a pan, or suchlike.

Some known cooking apparatuses are for example described in US 5 570 625 A and US 2014/123861 Al.

There is therefore a need to perfect a low temperature cooking method which can overcome at least one of the disadvantages of the state of the art.

To do this, it is necessary to solve the technical problem of cooking at a low temperature that allows to obtain a final product with a quality similar to that obtained by immersion cooking, reducing cooking times, even by up to a half.

In particular, one purpose of the present invention is to provide a cooking method and apparatus which allow to obtain a final product with a soft and juicy consistency without necessarily requiring the use of bags or vacuum equipment.

Another purpose of the present invention is to provide a low temperature cooking method and apparatus which allow to cook the products with limited cooking times and which is suitable to guarantee the safety of the cooking process, preventing the potential proliferation of bacteria from occurring in the products being cooked.

Another purpose of the present invention is to provide a cooking apparatus which can be used both to carry out cooking at low temperatures and also to perform any regeneration or finishing of the product itself.

Another purpose of the present invention is to provide a versatile cooking apparatus which allows to obtain different types of cooking according to requirements.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the purposes above and in order to solve the technical problem above in a new and original way, also achieving considerable advantages compared to the state of the art, a cooking method according to the present invention to cook foodstuff at low temperature, in particular meat or fish, provides to use a plate cooking device comprising a lower plate and an upper plate, opposite and facing each other, which are associated with respective heating elements.

In accordance with the present invention, the cooking method provides to dispose the foodstuff to be cooked between the lower plate and the upper plate, contained inside a space delimited by a containing element, with the upper plate positioned in contact at least with the containing element.

The method according to the invention also provides to determine a low temperature cooking profile based on the type of foodstuff and to keep the temperature and moisture controlled in the delimited space as above, cooking the foodstuff with a temperature comprised between 50°C and 120°C and reducing to a minimum a time interval in which the foodstuff remains within a temperature zone at risk of bacterial proliferation.

According to one aspect of the invention, the method provides to use, as a containing device, a containing accessory with the shape of a frame, and the foodstuff is positioned directly in contact with a surface of the lower plate. In this way, a direct heat transfer is achieved from the plate to the foodstuff, while still guaranteeing a correct degree of moisture around the foodstuff so as to prevent it from drying out, keeping it soft and juicy.

In accordance with one aspect of the present invention, the method provides to position and attach the containing frame to a plate and to position the foodstuff substantially in the center of the containing frame, in contact at least with the lower plate.

According to one variant, the cooking method provides to use, as a containing element, a cooking bag made of heat-resistant plastic material, for example of the type normally used to cook foodstuff in an oven at high temperature, up to about 220°C. These bags allow to keep foodstuff in an atmosphere that is controlled in terms of moisture, so as to obtain soft and juicy foodstuff. Unlike what occurs in a traditional use in an oven, in which it is necessary to pay attention to ensure that these bags do not come into contact with surfaces of the oven that have very high temperatures, because the method according to the invention provides to cook at a low temperature these problems do not occur.

In accordance with one aspect of the present invention, the method provides to receive a setting on the type of foodstuff and to determine the cooking profile by selecting it from a plurality of predefined cooking profiles stored in a memory unit.

In accordance with one aspect of the present invention, the method provides to receive a setting on the temperature of the plates correlated to the foodstuff and to determine its cooking as a function of this setting.

In accordance with one aspect of the present invention, the method provides to detect the temperature at the core of the foodstuff during cooking by means of a temperature probe, and to carry out a feedback control of the heating elements on the basis of the temperature detected.

In accordance with one aspect of the present invention, the method provides to monitor the ramp up gradient of the temperature of the foodstuff and, if it is lower than a predetermined value, to modify the electric power delivered to the heating elements in order to guarantee that the safety temperatures at the core of said foodstuff are reached within the minimum times allowed, so that the foodstuff does not remain in the temperature zone at risk of bacterial proliferation beyond determinate maximum safety times.

In accordance with another aspect of the present invention, the method provides to regulate the heating ramp ups and the operating temperature of the heating elements in such a way as to allow a secure use of the cooking bags, in order to guarantee that the plastic material that they consist of is not overheated, altered or melted.

In accordance with another aspect of the present invention, at the end of the cooking process the method provides to rapidly cool the foodstuff in order to preserve it.

In accordance with another aspect of the present invention, at the end of the cooking process the method provides to increase the temperature at least of the lower plate in order to brown the foodstuff and give it a browning and a flavor typical of a foodstuff cooked on a grill.

Advantageously, this step can be carried out with the same cooking apparatus. If a cooking bag is used, it is sufficient to remove the foodstuff from inside the bag and position it directly in contact with the lower plate. If the containing frame is used, it can be done directly, without needing to move the foodstuff in any way whatsoever.

The invention also concerns an apparatus for cooking foodstuff at low temperature.

In accordance with one aspect of the present invention, the apparatus comprises a plate cooking device comprising a lower plate and an upper plate opposite and facing each other, which are associated with respective heating elements, and a containing element having the shape of a frame that can be positioned in a removable manner between the two plates and is configured to delimit, together with the first and second plate, a space defining a cooking chamber for a foodstuff.

During cooking, the foodstuff can be advantageously positioned inside the chamber which is delimited laterally by the containing element and in direct contact at least with the lower plate.

The frame-shaped containing element advantageously guarantees that optimal conditions for cooking are achieved, and in particular the maintenance of a high degree of moisture, preventing the superficial dehydration of the foodstuff due to contact with the heated plate, and a reduced oxygen content in the immediate vicinity of the foodstuff itself so as to obtain a soft and juicy product.

The frame-shaped containing element associated with the apparatus therefore allows to cook the foodstuff at low temperature, that is, comprised between 50°C and 120°C, directly in contact with a plate, without needing to immerse the foodstuff in water, obtaining qualitatively similar results to the state of the art but with shorter cooking times. The finishing of the foodstuff, that is, its browning, can also be achieved by means of the same apparatus.

According to another aspect of the present invention, the apparatus comprises a control and command unit configured to command the functioning of the heating elements according to a determinate low temperature cooking profile, in which the temperature is comprised between about 50°C and 120°C in order to achieve both a control of the temperature and also a control of the moisture inside the cooking chamber.

Preferably, the control unit is configured to carry out a control of the heating elements on the basis of a cooking profile processed by means of special algorithms as a function at least of the type of foodstuff to be cooked, in order to reduce to a minimum the time interval during which the foodstuff remains in the bacterial proliferation risk zone, comprised between 10°C and 55°C.

According to one aspect of the present invention, the frame-shaped containing element is of the rigid type and, during use, when it is disposed between the two plates, the upper plate rests on it, regardless of the thickness of the foodstuff to be cooked.

According to yet another aspect of the present invention, the frame-shaped containing element has a bellows-type conformation, with walls having a zig-zag pattern, suitable to elastically deform and adapt, substantially continuously, the height of the cooking chamber in relation to the thickness of the foodstuff to be cooked. In this way, intimate contact is achieved between the plates and the foodstuff, limiting air spaces. In addition, the diffusion of moisture toward the outside and the entry of oxygen are limited.

According to another aspect of the present invention, the frame-shaped containing element has a telescopic conformation, comprising two or more strips, respectively extendable and retractable one into the other, in such a way as to adapt the height of the cooking chamber to the thickness of the foodstuff at least within a determinate range of values.

In accordance with another aspect of the present invention, the frame-shaped containing element can be attached to the lower plate or to the upper plate by means of removable attachment means such as hooks, magnets, same-shape coupling elements or suchlike, in order to facilitate cooking operations and/or the positioning of the foodstuff to be cooked.

According to another aspect of the present invention, the apparatus can comprise detection devices suitable to detect the presence of the containing element and transmit the information to the control unit, for example associated with the plate provided with the attachment means.

In accordance with another aspect of the present invention, the detection sensors can comprise an electromechanical or magnetic sensor configured to interact with the containing element.

The control unit can be configured to receive the data detected and based on the data, set a low temperature cooking functioning mode or a traditional medium or high temperature functioning mode.

Other embodiments described here also concern a cooking apparatus comprising a plate grill comprising a lower plate and an upper plate opposite and facing each other, which are associated with respective heating elements and at least one cooking bag made of heat-resistant plastic material, suitable to contain a foodstuff delimiting a space around it, and able to be positioned, during use, between the two plates.

According to another aspect of the present invention, the apparatus comprises a control and command unit configured to command the functioning of the heating elements according to a determinate low temperature cooking profile, in which the temperature is comprised between about 50°C and 120°C in order to obtain both a control of the temperature and also a control of the moisture inside the cooking chamber.

Furthermore, the control and command unit is configured to regulate the heating ramp ups and the operating temperatures of the heating elements in order to allow a secure use of the cooking bags and to guarantee that the plastic material that they consists of is not overheated, altered or melted.

According to another aspect of the present invention, the apparatus comprises a temperature probe which can be inserted in the foodstuff through an aperture made through in the containing element, or respectively an aperture of the bag, and the control unit is configured to control the heating elements also as a function of the data received from the temperature probe, thus performing a feedback control. This guarantees that a safety temperature above the risk zone is reached within the maximum times allowed.

The maximum times allowed in the risk zone and the minimum and maximum temperature levels defining the risk zone can be stored in a memory unit connected to the control unit. In accordance with another aspect of the present invention, the control unit can provide information relating to the cooking process, such as for example the estimated cooking time or the temperature in the center of the foodstuff, on a user interface, installed on board the machine, or provided on an electronic device on which a dedicated software application is installed.

BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a schematic three-dimensional view of a cooking apparatus according to the present invention with a containing element in accordance with a first embodiment;

- fig. 2 is a schematic front view of the cooking apparatus of fig. 1 in an operating condition;

- fig. 3 is a schematic three-dimensional view of a containing element in accordance with a second embodiment;

- fig. 4 is a schematic front view of a cooking apparatus according to the invention with the containing element of fig. 3 in an operating condition;

- fig. 5 is a schematic three-dimensional view of a containing element in accordance with a third embodiment;

- fig. 6 is a qualitative graph of the trend over time of a temperature profile of the plates of the cooking apparatus and of a foodstuff disposed between them;

- fig. 7 is a schematic three-dimensional view of a cooking apparatus according to the present invention in accordance with a second embodiment;

- fig. 8 is a schematic front view of the cooking apparatus of fig. 6 in an operating condition.

We must clarify that, in the present description, the sole function of the phraseology and terminology used, as well as of the illustrations in the attached drawings, also because of how they are described, is to illustrate and better explain the present invention, since their function is to explain the invention itself in a non-limiting manner and the scope of protection is defined by the claims.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be combined with, or incorporated into, other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

With reference to fig. 1, there is described a first embodiment of an apparatus 10 according to the present invention for cooking foodstuff 100 at low temperature, in particular meat or fish, whole or sliced, of various sizes, although plant-based foodstuff is not excluded.

The apparatus 10 according to the present invention comprises a plate cooking device 11 comprising a lower plate 12 and an upper plate 13 opposite and facing each other, which are associated with respective heating elements 14, 15 having at least one electric resistance.

The heating elements 14, 15 can be attached and/or welded to the respective plate 12, 13, or be disposed in a proximal position thereto.

The upper plate 13 can be associated with hinge means 17 by means of which it can rotate with respect to the lower plate 12 and possibly move toward and away from it, in order to adapt to the thickness of the foodstuff 11 to be cooked and/or be positioned at a determinate height with respect to the lower plate 12.

The plates 12, 13 can have the same or different surface conformations, for example smooth, lined, mixed, or with other conformations.

The apparatus 10 also comprises a containing element 16, which can be removably positioned between the lower plate 12 and the upper plate 13, and is configured to delimit, together with the two plates 12, 13, a space S defining a cooking chamber 18, in which the foodstuff 100 is positioned, substantially closed on all sides, defining a closed environment with controlled temperature and moisture.

The containing element 16 preferably has the shape of a frame, that is, it comprises a continuous lateral wall 19, or it comprises a plurality of segments adjacent to each other, delimited by respective lower 20 and upper 21 edges.

The frame-shaped containing element 16 guarantees optimal conditions for cooking, and in particular the maintenance of an environment that has a high degree of moisture and a reduced oxygen content around the foodstuff 100. In this way, low temperature cooking can be carried out obtaining a foodstuff 100 of high quality, similar to that of sous vide cooking, but with much shorter cooking times.

According to some embodiments, the containing element 16 can be attached to the lower plate 12 and/or to the upper plate 13 by means of removable attachment means 35 such as hooks, magnets, same shape coupling elements or suchlike, in order to facilitate cooking operations and/or the positioning of the foodstuff 100 to be cooked.

According to another aspect of the present invention, the apparatus 10 comprises a control unit 24 configured to command the functioning of the heating elements 14, 15 according to a determinate cooking profile, in particular a low temperature one, comprised between about 50°C and 120°C, suitable to give softness and juiciness to the foodstuff 100.

In particular, the low temperature cooking profile provides that the temperature of the plates 12, 13 is always kept below 120°C, preferably even below 100°C, so that the temperature reached by the foodstuff 100 being cooked necessarily remains lower or at most equal to this value.

According to some embodiments, the temperature of the two plates 12, 13 can be the same or different.

According to some embodiments, it can be provided that one of the two plates 12, 13 is heated to a maximum temperature which is lower than the maximum temperature of the other plate 13, 12, for example about 5-10% lower.

The control unit 24 can be configured to carry out both low temperature cooking and also medium or high temperature cooking, in the traditional way, as a function of a setting or command received.

Preferably, the control unit 24 is configured to carry out a control of the heating elements 14, 15 on the basis of a low temperature cooking profile elaborated by means of a cooking algorithm as a function at least of the type of foodstuff 100 in order to obtain a low temperature cooking guaranteeing that the foodstuff 100 is safe.

In particular, a determinate minimum temperature value and/or a possible maximum temperature value can be associated with each type of foodstuff 100, for example chosen from beef, veal, pork, poultry or fish, sliced or whole. The minimum and/or maximum temperature values can be defined, as well as on the basis of the type of foodstuff 100, also on the basis of the type of cut, or the thickness of the foodstuff 100.

By way of example, a minimum temperature value of 55°C can be defined for a whole piece of beef, while a minimum temperature value of 72°C can be defined for pork.

In relation to the type of foodstuff 100 and/or the type of cut or thickness, respective cooking times can also be defined, for example comprised between 20 minutes and a few hours.

According to some embodiments, the control unit 24 can be configured to alternately turn the heating elements 14, 15 on and off according to predefined time intervals in order to maintain an average temperature value around the desired value, preventing it from increasing beyond a determinate maximum value defined by the desired cooking profile.

The control unit 24 can also regulate the frequency with which the heating elements 14, 15 are switched on/off of as a function of the type of foodstuff 100 or the cooking profile selected.

The minimum and/or maximum temperature values and cooking times can be stored in a memory unit 25 connected to and communicating with the control unit 24.

In addition, in the memory unit 25 there can also be stored information about a risk temperature zone, that is, a temperature range within which there is a high risk of bacterial proliferation, normally comprised between 10°C and 55°C. The maximum permissible residence times within the risk zone, that is, the minimum and maximum threshold levels defining the risk zone, can also be stored in the memory unit 25.

The control unit 24 can be configured, in particular, to determine the cooking profile of a foodstuff 100 in such a way as to reduce to a minimum the duration of the time during which the temperature of the foodstuff 100 remains within the risk temperature zone.

The cooking profiles can be defined on the basis of the data stored in the memory unit 25 and can comprise the functioning operating parameters of the components of the cooking apparatus 10. The cooking profiles can provide respective differentiated temperature ramp ups, for example of the linear or stepped type, different residence times of the foodstuff 100 at different temperatures, different cooking times, in order to support slow and low temperature cooking but at the same time guarantee the safety limits in order to prevent any bacterial proliferation.

For example, a given cooking profile can be provided for each foodstuff 100 which allows to reduce to a minimum the amount of time the foodstuff 100 remains within the temperature zone at risk of bacterial proliferation, such profile can be predefined and stored in the memory unit 25.

The cooking profiles can, for example, comprise information regarding what the temperature has to be, or the operating parameters with which the heating elements 14, 15 have to be adjusted so that a standard portion, of a defined weight and/or size, of a foodstuff 100 of a certain type is rapidly heated beyond the temperature zone at risk of bacterial proliferation.

The cooking profiles can also comprise information regarding the expected heating speed for a given foodstuff 100, that is, the ramp up gradient of the temperature for the standard portion considered, with the operating parameters provided, so as to be able to carry out any checks on the actual operation of the apparatus.

The cooking profiles can also comprise information regarding a safety temperature that a given foodstuff 100 has to reach within a given time interval. By safety temperature we generally mean a temperature at which the growth of bacteria is reduced, for example a temperature above 60°C. However, it can also be provided that for each foodstuff 100 or for each cooking profile a specific predefined value is provided.

The cooking profiles can for example be defined and processed on the basis of tests carried out in the laboratory, or on the basis of tables defining a correlation between heating speed, temperature gradient and type of foodstuff 100.

The cooking profile can be selected and/or processed by the control unit 24 on the basis of settings supplied by a user by means of special commands 31, 32 of a user interface 30, for example in the form of buttons, knobs, or a touch screen.

In the first case, it can be provided that predefined cooking profiles are pre stored, or even able to be stored, in the memory unit 25, each associated with one or more characteristics that can be selected by means of the user interface 30, for example chosen from type of foodstuff, thickness of the foodstuff, weight of the foodstuff, or type of cooking desired, and the control unit 24 can select the suitable cooking profile on the basis of the input data received.

In the second case, the control unit 24 can comprise processing means or algorithms suitable to process and calculate the cooking profile on the basis of the input data received by means of the user interface 30 and on the basis of the minimum and maximum temperature values stored.

It can also be provided that a user, by means of the commands 31, 32 can set a desired temperature for the plates 12, 13, for example on the basis of predefined tables detailing the cooking profiles suitable for different types of foodstuff 100, and the control unit 24 is configured to determine the cooking profile on the basis of the settings received.

In accordance with another aspect of the present invention, the user interface 30 can be installed on board the apparatus 10, or be provided on an electronic device on which a dedicated software application is installed, communicating wirelessly with the control unit 24 of the apparatus 10, directly or via the cloud.

The interface 30 can also comprise a display device 33 by means of which the control unit 24 can provide the user with information relating to the cooking process, such as the estimated cooking time, or the core temperature of the foodstuff 100.

In accordance with some embodiments, the apparatus 10 can comprise a temperature probe 26 configured to be inserted in the foodstuff 100 being cooked and detect the core temperature of the foodstuff 100.

The temperature probe 26 can comprise a distal end 27 with a thin and elongated shape, which can be inserted in the foodstuff 100, configured to acquire the core temperature of the foodstuff 100 in real time, and a proximal end

28 in which control and/or power supply means can be provided.

According to this solution, the containing element 16 can be provided with at least one aperture 29 made through in the lateral wall 19 and having a size suitable for the passage of the distal end 27.

According to possible solutions not shown, it can be provided that the aperture

29 is made of a deformable material suitable to deform upon insertion of the temperature probe 26 and to close again when the temperature probe 26 is not present so as to keep the chamber 18 closed.

The control unit 24 can be connected to the temperature probe 26 by means of a cable or also in wireless mode, and be configured to control the heating elements 14, 15 also as a function of the data received from the temperature probe 26 in order to achieve a feedback control of the process.

In accordance with possible solutions, the control unit 24 can comprise processing means or algorithms suitable to receive the data acquired by the temperature probe 26 and analyze it in order to verify whether the foodstuff 100 has reached a correct cooking temperature within the preestablished times, or if corrective actions are necessary to guarantee the foodstuff is safe, for example if it is necessary to provide an extension of the cooking time or an increase in the minimum cooking temperature value.

Thanks to the temperature probe 26 positioned at the core of the foodstuff 100 and to the processing means, the control unit 24 can monitor the temperature ramp up gradient. In some conditions, when the temperature ramp up gradient is lower than a predetermined value, the control unit 24 can intervene by modifying the electric power delivered to the heating elements 14, 15, so as to guarantee that the safety temperatures at the core of foodstuff 100 are reached within the maximum time allowed. In this way, bacterial growth is limited and the preservation of the foodstuff 100 after cooking is guaranteed.

According to some embodiments, the control unit 24 comprises a PID-type control algorithm having an accuracy level of +/- 1°C suitable to monitor the temperature gradient.

By way of example, fig. 6 shows a graph that sets out a temperature profile of the plates 12 and 13 for cooking a foodstuff 100 as a function of time with the cooking apparatus 10 according to the invention. In the graph, the solid line indicates the temperature trend of the lower plate 12, the dotted line indicates the temperature trend of the upper plate 13 and the dash-dot line indicates the temperature trend of the foodstuff 100.

As can be seen, after an ignition instance tO, the temperatures of the plates 12, 13 increase according to predefined ramp ups and subsequently, at the end of the initial transitory phase, they follow a sinusoidal trend with a period determined by the frequency with which the respective heating elements 14, 15 are switched on and off, defined by the control unit 24. As stated above, this regulation mode allows to keep the temperatures of the plates 12, 13 around a predefined maximum value which, in the example case, does not exceed 95°C for the lower plate 12 and is lower than 90°C for the upper plate 13.

The temperatures of the plates 12, 13 are regulated in order to minimize the time interval At defined between the instants tl and t2, in which the foodstuff 100 remains within the zone at risk of bacterial proliferation between 10°C and 55°C. This time interval At can be for example less than 20 min, preferably less than 15 min, as a function of the type of foodstuff 100.

The trend of the temperature of the foodstuff 100 can optionally be monitored by means of the probe 26 in order to perform a feedback control and, on the basis of the signal received from the probe 26, the control unit 24 can possibly modify the frequency with which the heating elements 14, 15 are switched on and off, in order to increase it and/or decrease the average temperature value also on the basis of the estimated duration of the time interval At.

The apparatus 10 can comprise detection devices 36 suitable to detect the presence of the containing element 16 and transmit the information to the control unit 24; the devices 36 can be associated with the same plate 12, 13 provided with the attachment means 35.

In accordance with another aspect of the present invention, the devices 36 can comprise an electromechanical or magnetic sensor configured to interact with the containing element 16.

The control unit 24, in relation to the presence or absence of the containing element 16, can be configured to set a low temperature cooking mode or other cooking mode.

According to the embodiment of figs. 1 and 2, the containing element 16 is of the rigid type and, during use, when it is disposed between the two plates 12, 13, the upper plate rests on it, regardless of the thickness of the foodstuff 100 to be cooked.

In figs. 3 and 4, the containing element 116 has a bellows-type conformation, in which the lateral wall 19, that is, each segment of wall, has a zig-zag pattern, and is suitable to deform elastically in order to adapt, substantially continuously, the height of the chamber 18 in relation to the thickness of the foodstuff 100 to be cooked.

During use, the upper plate 13 resting on the upper edge 20 can compress the lateral wall 19 until it is positioned resting on the foodstuff 100, so that it is in direct contact with both the heating surfaces 22, 23 of the two plates 12, 13.

In fig. 5, the containing element 216 can have a telescopic structure, comprising two or more strips 37a, 37b, 37c respectively extendable and retractable one into the other, so as to adapt the height of the chamber 18 to the thickness of the foodstuff 100. In this case, it can be provided that the lateral wall 19 can assume two or more height values, or that the strips 37a, 37b, 37c are reciprocally mobile in a continuous or discreet manner, and are provided with clamping means suitable to clamp them in a determinate position.

According to another aspect of the invention, the containing elements 16, 116, 216 can be equipped with lateral apertures 38 made in the respective lateral wall/walls 19, through which a flow of air can pass.

These lateral apertures 38 can be advantageously associated with closing elements 39, for example of the shutter type, which can be selectively driven to modify and adjust the passage section for the flow of air and manage the degree of moisture inside the chamber 18.

Figs. 7 and 8 show a second embodiment of a cooking apparatus 110 for cooking foodstuff at low temperature. The elements identical to those of the first embodiment of fig. 1 are indicated with the same reference numbers and are not described again.

The cooking apparatus 110 comprises a plate cooking device 11 and a cooking bag 50 that functions as a containing element, configured to contain a foodstuff and delimit a space S around it.

The cooking bag 50 can be a bag made of heat-resistant plastic material of the type present on the market, for example made of PET.

Also in this embodiment, the apparatus 110 comprises a control unit 24 configured to command the functioning of the heating elements 14, 15 according to a determinate cooking profile, in particular a low temperature one, comprised between about 50°C and 120°C, suitable to give softness and juiciness to the foodstuff 100 while at the same time guaranteeing that the foodstuff 100 is safe. In terms of qualitative trend and of temperatures involved, the cooking profiles for a given foodstuff 100 in the event a containing element 16 or a cooking bag 50 is used can be substantially similar to each other, possibly providing a difference of a few degrees more or less, for example 2-3 °C.

According to this embodiment, the control unit 24 can also be configured to regulate the heating ramp ups and the operating temperatures of the heating elements 14, 15 in order to allow a safe use of cooking bags 50 and to guarantee that the plastic material that they consists of is not overheated, altered or melted.

Also according to this embodiment, the apparatus 110 can comprise a temperature probe 26 configured to be inserted in the foodstuff 100 being cooked and to detect the temperature at the core of the foodstuff 100. In this specific case, the distal end 27 can be inserted inside the bag 50 through an aperture 51 thereof.

The cooking method according to the present invention, which can be carried out with one or the other of the cooking apparatuses 10, 110 according to the present invention described above, comprises the following steps.

- disposing the foodstuff 100 to be cooked between the lower plate 12 and the upper plate 13, contained inside a space S delimited by a containing element 16, 50;

- positioning the upper plate 13 in contact at least with the containing element 16, 50;

- determining a low temperature cooking profile at least as a function of the type of foodstuff 100 to be cooked;

- controlling the heating elements 14, 15 on the basis of the cooking profile determined, in order to maintain a controlled temperature and moisture within the delimited space S and cook the foodstuff 100 with a temperature comprised between 50°C and 120°C, reducing to a minimum a time interval in which the foodstuff 100 remains within a temperature zone at risk of bacterial proliferation.

According to some embodiments, the method provides to determine the cooking profile on the basis of data and information stored in the memory unit 25. The data can comprise one or more of either minimum or maximum temperature values associated with a determinate type of foodstuff 100, cooking times, maximum residence times of the type of foodstuff 100 in a bacterial proliferation risk zone, threshold levels of the risk zone, temperature ramp up gradients. The minimum and maximum temperature values, cooking times, and maximum residence times can be defined on the basis of the safety requirements imposed by legislation and/or on the basis of tests and experiments carried out.

The method can provide to determine the cooking profile on the basis of settings provided by a user by means of special commands 31, 32 of a user interface 30, wherein determining the cooking profile can comprise at least one of either selecting a cooking profile among a plurality of predefined cooking profiles stored in the memory unit 25, or processing a specific cooking profile by means of the processing means 34.

According to some embodiments, the method according to the invention provides to detect the temperature at the core of the foodstuff 100 by means of a temperature probe 26 inserted through an aperture 29, 51 of the containing element 16, 50 and to carry out a feedback control of the heating elements 14, 15 on the basis of the data detected.

The method can also provide to monitor the ramp up gradient of the temperature of the foodstuff 100 and, in the event that it is lower than a predetermined value, to modify the electric power delivered to the heating elements 14, 15 in order to guarantee that the safety temperatures are reached at the core of the foodstuff 100 within the maximum time allowed. The predetermined value can be, in particular, the expected value provided by the cooking profile being used.

According to some embodiments, the method provides to use a containing accessory 16, 116, 216 of the frame-shaped type as the containing element.

In this case, the method according to the invention can provide to detect the presence of the containing element 16, 116, 216 by means of the detection devices 36 before starting the low temperature cooking process.

According to some variants, the method provides to use a cooking bag 50 as a containing element and to dispose the foodstuff 100 to be cooked enclosed inside it.

In this case, the method can provide to regulate the heating ramp ups and the operating temperature of the heating elements in such a way as to allow safe use of the cooking bags 50, in order to guarantee that the plastic material which they consists of is not overheated, altered or melted, but at the same time keep to a minimum the above mentioned time interval in which the foodstuff 100 remains within the temperature zone at risk of bacterial proliferation.

For example, in the memory unit 25 there can be stored a first group of cooking profiles comprising information on the operating parameters to be used for the heating elements 14, 15 to be used when the use of a containing element 16, 116, 216 is provided, and a second group of cooking profiles comprising information on the operating parameters to be used for the heating elements 14, 15 to be used when the use of a cooking bag 50 is provided. The control unit 24, as a function of the type of containing element 16, 116, 216 or of the cooking bag 50, can therefore, on each occasion, select or make available to a user the choice between suitable cooking profiles.

It is clear that modifications and/or additions of parts may be made to the cooking apparatus 10, 110 and method as described heretofore, without departing from the field and scope of the present invention as defined by the claims.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of cooking apparatus 10, 110 and method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

In the following claims, the sole purpose of the references in brackets is to facilitate reading: they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.

Claims

1. Method to cook foodstuff (100) at low temperature in an apparatus (10; 110) comprising a plate cooking device (11) with a lower plate (12) and an upper plate (13) opposite and facing each other and associated with heating elements (14, 15), wherein:

- said foodstuff (100) is disposed between the two plates (12, 13) contained in a space (S) delimited by a containing element (16; 116; 216; 50);

- said upper plate (13) is positioned in contact at least with said containing element (16; 116; 216; 50);

- a low temperature cooking profile is determined on the basis of said foodstuff

(100);

- a temperature and a moisture are kept controlled in said delimited space (S) by cooking said foodstuff (100) at a temperature comprised between 50°C and 120°C and by reducing to a minimum a time interval in which said foodstuff (100) remains within a temperature zone at risk of bacterial proliferation.

2. Cooking method as in claim 1, characterized in that it provides to use as containing element (16; 116; 216) an accessory having the shape of a frame, which can be removably positioned between said plates (12, 13) and is configured to define with them a substantially closed cooking chamber (18) defining said space (S), and to position said foodstuff (100) directly in contact with a surface of said lower plate (12).

3. Cooking method as in claim 1, characterized in that it provides to use as containing element a cooking bag (50) made of heat-resistant plastic material, which delimits said space (S).

4. Cooking method as in any claim hereinbefore, characterized in that it provides to receive a setting on the type of foodstuff (100) to be cooked and to determine the cooking profile by selecting it from a plurality of predefined cooking profiles stored in a memory unit (25).

5. Cooking method as in any claim hereinbefore, characterized in that it provides to receive a setting on the temperature of said plates (12, 13) correlated to a type of foodstuff (100) to be cooked, and to determine the cooking profile as a function of this setting.

6. Cooking method as in any claim hereinbefore, characterized in that it provides to detect the temperature at the core of said foodstuff (100) by means of a temperature probe (26) and to carry out a feedback control of said heating elements (14, 15) on the basis of the temperature detected.

7. Cooking method as in claim 6, characterized in that it provides to monitor the ramp up gradient of the temperature of said foodstuff (100) and, if it is lower than a predetermined value, to modify the electric power delivered to said heating elements (14, 15) in order to guarantee that the safety temperatures at the core of said foodstuff (100) are reached within the maximum times allowed.

8. Cooking method as in any claim hereinbefore, characterized in that when the cooking of said foodstuff (100) has ended, it provides to increase the temperature at least of said lower plate (12) in order to carry out a browning and finishing of said foodstuff (100).

9. Cooking method as in any claim hereinbefore when it depends on claim 3, characterized in that it provides to regulate the heating ramp ups and the operating temperature of said heating elements (14, 15) in such a way as to allow safe use of the cooking bag (50) in order to guarantee that the plastic material it consists of is not overheated, altered or melted, but at the same time keep to a minimum said time interval in which said foodstuff (100) remains within the temperature zone at risk of bacterial proliferation.

10. Apparatus (10) for cooking foodstuff (100) at low temperature comprising a plate cooking device (11) with a lower plate (12) and an upper plate (13) associated with respective heating elements (14, 15), characterized in that it comprises a containing element (16; 116; 216) having the shape of a frame, which can be removably positioned between said plates (12, 13) and is configured to delimit together with them a space (S) defining a substantially closed cooking chamber (18) for said foodstuff (100), and a control unit (24) configured to control the functioning of said heating elements (14, 15) on the basis of a cooking profile determined by means of processing means (34), in order to maintain a desired temperature and moisture in said space (S) of said chamber (18), thus cooking said foodstuff (100) with a temperature comprised between 50°C and 120°C.

11. Apparatus (10) as in claim 10, characterized in that said containing element (16; 116; 216) is rigid. 12. Apparatus (10) as in claim 10, characterized in that said containing element (16; 116; 216) has a bellows-type conformation, suitable to compress and extend according to the height and thickness of said foodstuff (100).

13. Apparatus (10) as in claim 10, characterized in that said containing element (16; 116; 216) has a telescopic conformation comprising two or more strips (37a, 37b, 37c).

14. Apparatus (10) as in any previous claim from 10 to 13, characterized in that it comprises removable attachment means (35) for connecting said containing element (16; 116; 216) to at least one of said lower (12) and/or upper (13) plates.

15. Apparatus (10) as in any previous claim from 10 to 14, characterized in that it comprises detection devices (36) suitable to detect the presence of said containing element (16; 116; 216) and transmit the information to said control unit (24).

16. Apparatus (10) as in any previous claim from 10 to 15, characterized in that said containing element (16; 116; 216) is provided with adjustable lateral apertures (38).

17. Apparatus (110) for cooking foodstuff (100) at low temperature comprising a lower plate (12) and an upper plate (13) associated with respective heating elements (14, 15), characterized in that it comprises at least one cooking bag (50) made of heat-resistant plastic material, suitable to contain a foodstuff (100) delimiting a space (S) around it and which during use can be positioned between said plates (12, 13), and a control unit (24) configured to control the functioning of said heating elements (14, 15) on the basis of a cooking profile determined by means of processing means (34), in order to maintain a desired temperature and moisture in said space (S) delimited around said foodstuff (100), thus cooking said foodstuff (100) with a temperature comprised between 50°C and 120°C.

18. Apparatus (110) as in claim 17, characterized in that said control unit (24) is configured to regulate the heating ramp ups and the operating temperatures of said heating elements (14, 15) in order to allow a secure use of said at least one cooking bag (50) and guarantee that the plastic material that it consists of is not overheated, altered or melted, but at the same time keep to a minimum said time interval in which said foodstuff (100) remains within the temperature zone at risk of bacterial proliferation. 19. Apparatus (10; 110) as in any previous claim from 10 to 17, characterized in that it comprises a temperature probe (26) which can be inserted in said foodstuff (100) able to transmit the data collected to said control unit (24) which carries out a feedback control of said heating elements (14, 15).