DK2789918T3

DK2789918T3 - Method of preparing a food and cooking device

Info

Publication number: DK2789918T3
Application number: DK13001792.4T
Authority: DK
Inventors: Pascal Feierabend; Nina Dohner
Original assignee: V-Zug Ag
Priority date: 2013-04-08
Filing date: 2013-04-08
Publication date: 2017-02-06
Also published as: AU2014252686A1; HK1221005A1; SI2789918T1; CN105308393A; WO2014166005A1; EP2789918A1; AU2014252686B2; PL2789918T3; EP2789918B1; CN105308393B

Description

Technical Field

The invention relates to a method for cooking food, in particular with steam, and a correspondingly designed cooking device.

Background DE 10 2004 040 655 A1 describes a method and a device for regulating a delta-T-cooking process. Thereby, the current cooking chamber temperature is set depending on the current core temperature during a first time interval in such a way that an essentially constant difference, the delta-T-value, maintains between these two values. EP 723115 A2 describes a method for cooking meat wherein the cooking chamber is heated up with hot air in a food temperature regulating phase in such a way that the food temperature follows a time-dependent desired food temperature function. In this way a certain food temperature (core temperature) can be reached at a desired time. However, it has been found that it takes relatively long until the food has been cooked by following this procedure because the slope of the time-dependent desired food temperature function must not be chosen to be too steep in order to avoid local overheating at the meat surface. EP2537418 A1 describes a method for cooking food, for example meat, in a cooking device with steam, wherein the food is sealed in a bag. The cooking chamber is heated with steam, wherein a food temperature is measured by a food temperature measurement probe and regulated by a regulating loop on an increasing ramp until it has reached an end food temperature. Simultaneously the cooking chamber temperature is supervised in order not to exceed a limit. Afterwards an optional high temperature phase follows with increased temperature. The food can be cooked quickly and in a gentle manner by this method.

Although cooking with steam is recognized as gentle, the use of a bag for sealing the food is a limitation in usability of the oven. Therefore an objective is to develop gentle steam cooking methods which do not depend on the sealing of the food in a bag and still allow a gentle cooking of the food.

Disclosure of the Invention

In a method to operate an oven according to the present invention the food is inserted into their cooking chamber and the cooking chamber temperature is controlled in the cooking chamber in such a way that the food temperature follows a time-dependent desired food temperature function, wherein the desired food temperature function has at least a first phase and a second phase which follows the first phase and has a steeper gradient in the first phase as compared to the second phase .

For this purpose the cooking chamber is preferably heated by dosed insertion of steam (optionally by also using further heating means), with the result that a more efficient heat input in the food is made possible without having to use a very high temperature in the cooking chamber.

In a further preferred version of the method the food is heated in the cooking chamber without a steam isolated bag.

Preferably, the desired food temperature function is chosen such that it rises up to an end food temperature over time, such that the desired core temperature is reached at the end of the food temperature regulating phase. In a preferred version of the invention the desired function is therefore an approximation to an exponential course of the food temperature with a steep temperature increase during the first phase and a flat convergence to the end food temperature during the second phase. In a particularly preferred version of the invention the desired food temperature function is therefore monotonically increasing during the first and second phase, in particular strictly monotonic increasing, for example linearly increasing, wherein the second phase follows immediately after the first phase. A transmission between the first and the second phase can lie in a food temperature interval between 10°C and 30°C below the end food temperature.

The cooking duration or the end time when the food shall be finished can be preset. Preferably, the maximal cooking duration lies below 3h, which corresponds to a clearly shorter duration as compared to the usual soft cooking with steam.

Preferably, a preheating phase precedes the first and the second phase with the time dependent desired food temperature function. The preheating phase brings the food from an arbitrary initial temperature to a preprogrammed food temperature. It lies preferably in an interval between 20°C and 30°C, in particular preferably in an interval between 23°C and 27°C. Therefore the food is brought to an exactly determined temperature despite an arbitrary initial temperature, which for example can vary between cooling temperature and room temperature, before the first phase of the time dependent desired food temperature function begins.

Advantageously, it should be taken care that the cooking chamber temperature never rises too much. In a preferred embodiment this can be achieved by controlling the cooking chamber temperature in such a way that it surpasses the end food temperature by maximally 30°C, particularly maximally 15°C, particularly maximally 10°C. Alternatively or additionally, the cooking chamber temperature can be controlled in such a way that it doesn't surpass a predefined fixed limit temperature, wherein the fixed limit temperature is smaller than 105°C. During the preheating phase the cooking chamber temperature is preferably limited to a range between 60°C and 80°C.

As soon as the corresponding limit temperature is reached, the temperature is decreased below the desired food temperature function in order to make sure that the cooking chamber temperature doesn't increase further.

The invention is particularly suitable for cooking meat (wherein in the present context fish is also counted as meat) , because in this case the cooking process can be terminated after reaching the desired core temperature. In this case the end food temperature is chosen according to the generally known advantageous core temperature of the particular meat. The method may however also be used for other types of food, e.g. vegetables.

Brief Description of the Drawings

Further embodiments, advantages and applications of the invention result from the dependent claims and from the now following description by means of the figures. Thereby it is shown in:

Fig. 1 the most important components of a cooking device and

Fig. 2 the qualitative course of the food temperature TGG, the cooking chamber temperature TGR and the desired food temperature TGGS.

Modes for Carrying Out the Invention

The cooking device according to Fig. 1 has a cooking chamber 1 for receiving the food 2, e.g. on a metal plate or a grid 3. Furthermore, the device has a controller 4 and a steam generator 5. The steam generator 5 serves to heat up the cooking chamber 1 by means of steam. The steam generator 5 can produce overheated steam at a temperature above 100°C for example with additional hot air.

Further means for heating up the cooking chamber may also be present, e.g. resistive heaters. The cooking device is preferably an oven with a steam cooking function, it may however also be e.g. a pure steam cooking device.

The controller 4 comprises, amongst others, means 6 for generating a desired food temperature function, meaning a time-dependent desired value TGGS of the food temperature TGG. The means 6 may e.g. be a memory and computing means which generate such a function in a known way. Preferably, the mean 6 is formed such that the desired food temperature function TGGS comprises a first phase and a directly following second phase where in a food temperature regulating phase of the device initially increases from a start value and monotonically, in particular strictly monotonic, to an interim temperature, which lies for example 25°C below an end food temperature TGGE, and then increases with a flatter gradient, but still monotonically, in particular strictly monotonic, until the end food temperature TGGE. The gradients of the first and the second phase are set in such a way that the end food temperature TGGE is reached in a time period which can be set by a user via an input unit (not shown) of the oven. This time period can be of 3h or less.

Furthermore, the controller 4 comprises a first regulator 7 and a second regulator 8, each of which compare a current value with a desired value and generate a controlling variable in such a way that the current value adapts to the desired value.

The first regulator 7 is connected to a food temperature measurement probe 9. The latter measures the food temperature TGG approximately in the middle of the food 2, i.e. so-called core temperature. The desired value TGGS of the food temperature is supplied by the means 6 as desired value to the regulator 7. The regulator 7 compares the food temperature TGG and its desired value TGGS and generates from it a desired cooking chamber temperature TGRS which is chosen in such a way that the food temperature TGG tends to reach its desired value TGGS.

The second regulator 8 is connected to a cooking chamber temperature measurement probe 10. It measures the cooking chamber temperature TGR. The second regulator receives the desired value TGGS from the first regulator, compares it with the current cooking chamber temperature TGR and generates from it a control signal for the steam generator 5. This control signal controls the steam generation and is chosen in such a way that the cooking chamber temperature TGR tends to reach its desired value TGRS. If the device is controlled based on a preset cooking chamber temperature TGR, e.g. during the preheating phases described further, only this part of the control is necessary.

The regulators 7 and/or 8 or generally the controller 4 are advantageously formed in such a way that the cooking chamber temperature TGR doesn't surpass a limit temperature TLIM of 105°C. In this way a thermal damage of the food surface can be avoided.

In the following the cooking method carried out with the above cooking device will be described. It has to be noted, though, that the described cooking method corresponds to only one of multiple possible operating modes of the cooking device. The cooking device is normally able to cook food also by employing other conventional methods.

In the presently described operating mode the food temperature measurement probe 9 is first inserted into the food 2. In the embodiment according to Fig. 1 the measurement probe 9 has been inserted into the food 2 directly. A steam isolating bag, which protects the food from hot steam in the cooking chamber and which is described e.g. in EP 2537418 Al, is not used.

The food 2 provided with the measurement probe 9 is then inserted into the cooking chamber 1 and the cooking program is initiated. The following steps of this cooking program run automatically and are controlled by the controller 4. The course of the cooking temperature TGG, of the desired food temperature TGGS and the cooking chamber temperature TGR during the cooking program are shown in Fig. 2. Thereby, the food temperature TGG is illustrated with a dotted line overlaying the continuously drawn line of the desired food temperature value TGGS. The upper lines in Fig. 2 represent the cooking chamber temperature with two different courses TGR(l), TGR(2).

First the steam generator 5 is activated, such that the cooking chamber temperature TGR starts increasing. (Optionally the cooking chamber can be also heated e.g. by a resistive heater or another suitable heating means.) The cooking program illustrated in Fig. 2 starts at a time tO where the cooking chamber temperature is 60 °C.

During an optional first (pre-)heating phase, which serves for tempering the food in a gentle manner and for compensating different initial temperatures, the food is heated while measuring the food temperature. This phase ends at a time tl when the food has a selectable, preprogrammable food temperature, e.g. 20°C.

During a further optional second phase, which directly follows the first phase, the cooking for bigger food pieces is accelerated. The degree of acceleration can be evaluated by the course of the food temperature TGG during the first phase.

For example the cooking chamber temperature in the second phase can be derived from the duration of the first phase, where a first cooking chamber temperature TGR(l) is chosen at a duration not longer than a preset duration tl. This example this temperature is the initial temperature of 60°C. If the duration is longer than the preset duration tl, a second cooking chamber temperature TGR(2) can be chosen. This example this temperature is constantly 70°C as shown in Fig. 2 (after heating up) in order to accelerate the heating up of the food.

If the desired food temperature is still not reached after having reached a preset maximal duration tmax of the first phase, the first phase can be stopped and the following second phase can be initiated with a preset temperature which is even higher, e.g. 80°C. This course is not shown in Fig. 2.

In an alternative example the three temperature settings of 60°C, 70°C or 80°C for the second phase can also be derived from the gradient of the food temperature during the first heating phase.

During the optional second heating phase the food is heated up with the chosen cooking chamber temperature of 60°C, 70°C or 80°C until a (second) selectable food temperature, e.g. 25°C. If this temperature is not reached after a preset time t2, the cooking process is stopped by showing an error message to the user.

During these first two heating phases the temperature increase is determined by the cooking chamber temperature. The heating phase following these two optional preheating phases is controlled by the presetting of a desired food temperature function TGGS, i.e. a time dependent desired value TGGS of the food temperature TGG. In principle individual preheating phases can be controlled by a preset TGGS-function but such a control can increase the cooking chamber temperature TGR to a higher level than desired.

The desired value TGGS describes during the heating phase, as shown in Fig. 2, firstly a phase with steeply increasing desired values, followed by a flatter phase which ends by reaching the end food temperature TGGE. The desired food temperature function shown in Fig. 2 can be considered an exponential course of the type TGGE* (1-exp (-kt)) with k being a time constant which depends on the desired cooking time, which is approximated with two linear segments. As the curve initially increases steeper, it is avoided that the cooking chamber temperature TGR has a high value at the end of the heating phase. On the other hand an overshoot of the food temperature in particular in case of small food pieces can be better avoided as compared to a simple linear course as described for example in EP 2537418 A1.

The gradient of the first, steeper phase of the desired food temperature function can be chosen in such a way that the maximal heat insertion into the core of the food is possible without affecting quality of the final product of the cooking process. For meat the gradient is in the range from about 0.7°C/min to 1.5°C/min, in particular from about l.l°C/min to 1.3°C/min.

The second phase starts at a time t3a when the food temperature is increased to the end food temperature TGGE except for a defined temperature difference ΔΤ. This difference ΔΤ can be chosen for example in a range between 10°C and 30°C or 15°C and 30°C below the end food temperature, preferably in a range between 23°C and 27°C below the end food temperature.

The gradient of the second phase can then be determined by the relation between the temperature ΔΤ and the remaining cooking time t3b - t3a.

During this second phase the food is approached preferably flat to the end food temperature TGGE preferably without overshooting of the food temperature and near to the end food temperature TGGE. In this way the subsequent cooking of the food after the end of cooking is limited.

As shown in FIG. 2 a protective condition makes sure that the temperature of the cooking chamber is limited to a maximal temperature TLIM of 105°C during the whole phase. This temperature can be reached by using overheated steam and can even be exceeded.

The described method is suitable in particular for meat, as initially mentioned. But the method can also be applied for example for vegetables. In this case the cooking chamber temperature should be kept at the desired end food temperature TGGE for a certain time at the end of the food temperature regulating phase.

The food can be roasted, e.g. in a pan, if a distinct encrustation is desired.

While preferred embodiments of the invention have been described in this application, it is clearly noted that the invention is not restricted to them and may be carried out in other ways within the scope of the now following claims.

Claims

A method of preparing a food (2) in a cooking device with a cooking space (1) during a cooking period during which a food preparation temperature (TGG) is measured and where a cooking room temperature (TGR) is at least below a food preparation temperature control phase. of the cooking time is controlled in the cooking space outside the food (2) in such a way that food preparation temperatures (TGG) follow a time-dependent food preparation temperature setting value course (TGGS), characterized in that the food (2) introducing the preparation room (1) food preparation temperature (1) includes at least two different incremental areas where the second area following the first one has a smaller increment than the first area.

Process according to claim 1, characterized in that the cooking compartment (1) is heated at least partially by hot steam.

Process according to claim 1 or 2, characterized in that the food (2 is heated without steam-insulating clothing in the cooking space).

A method according to any one of the preceding claims, wherein the food preparation temperature setting value course (TGGS) is selected such that the temperature of the first and second regions increases monotonically until a final food preparation temperature (TGGE).

The method of claim 4, wherein the first and second ranges run linearly and the first region at a temperature selected from a range of between 10 ° C and 30 ° C under final food preparation temperatures (TGGE) in the second area.

A method according to any one of the preceding claims, wherein the pitch below the first range is at least on average between 0.7 ° C / min and 1.5 ° C / min

A method according to any one of the preceding claims, wherein the rise below the second region is determined from the temperature difference between the food preparation temperature at the end of the first region and the end of the food preparation temperature (TGGE) and a residual cooking period at the end of the first region.

A method according to any one of the preceding claims, wherein a preheating phase precedes food preparation temperature setting value course (TGGS) having at least two regions, the preheating phase bringing the food (2) to a predetermined temperature at the beginning of the first region.

The method of claim 8, wherein the cooking room temperature (TGR during the preheating phase is limited to a range of 60 ° C to 80 ° C.

The method of claim 8 or 9, wherein the food preparation temperature (TGG) is measured during the preheating phase and parameters for setting subsequent cooking room temperatures (TGR (1), TGR (2)) are derived from the food preparation temperature course.

A cooking device adapted to carry out a method according to any one of the preceding claims, with a cooking space (1) for recording of the food (2), a food preparation temperature measuring probe (9) for measuring the food temperature (2) (TGG) and a control unit (4) designed to control the cooking phase temperature (TGR) in the cooking space (1) in the food preparation temperature in such a way that the food (2) food preparation temperature (TGG) follows a time-dependent food preparation temperature setting temperature (TGGS) and that the food preparation temperature setting value course (TGGS) comprises at least two regions of different pitch, the second region following the first region having a lower pitch than the first region.

A cooking device according to claim 11 with a steam generator (5) for heating the cooking space (1) with steam.

The cooking device according to claim 11 or 12, wherein the food preparation temperature measuring probe (9) is configured to measure the food preparation temperature (TGG) of the food (2) without steam insulating coating.

The cooking device according to any one of claims 11 to 13, wherein the control units are designed in such a way that the rise of the food preparation temperature setting value course (TGGS) below the first range is of an average between 0.7 ° C / min and 1.5 °. C / min.

Cooking device according to one of claims 11 to 14, wherein control units (4) are designed to determine the increase under the second region from the free temperature difference between the food preparation temperature at the end of the first area and the final food preparation temperature (TGGE and a residual cooking time at the end of the the first area.

Cooking device according to one of claims 11 to 15, wherein control units (4) are designed to measure the food preparation temperature (TGG) and from the foodstuff during a heating phase preceding the food preparation rescue temperature control phase with the at least first and second ranges. to determine the parameters for setting according to the following cooking room temperatures (TGR).