FIELD OF THE INVENTION

The invention relates to a method for treating food, such as a method for hydrating food, a respective device that can be used for such method, and a kitchen appliance including such device.

BACKGROUND OF THE INVENTION

Methods for hydrating food are known in the art, e. g. from US 2006/0251788 Al . This document describes a food product and system and method of making in which the product includes a hydrated plurality of grain or seed based constituents. In a preferred embodiment of US 2006/0251788 Al, the product can be prepared by selecting one or more grain or seed based constituents, hydrating to a desired softness, then packaging and freezing. Optionally hydration is performed under reduced-pressure conditions. Amongst others, this document describes a method of manufacturing a food composition comprising: forming constituent parts, adding liquid to the constituent parts, applying vacuum pressure to the combined constituent parts and liquid, waiting during a hydration period a sufficient period to hydrate the constituent parts, and forming a food product with the hydrated constituent parts.

WO2016077360A1 describes food stuffs which are cooked at precise temperatures, which are optionally below 100°C, in a vessel that is evacuated to exclude air, in which low pressure steam replaces the air. When a sufficient quantity of air is excluded and replaced with water vapor, the temperature of vapor is accurately measured inside the vessel below the lid to control the temperatures within about 1° C. Air is preferably excluded via a controlled heated process for a relatively short period of time at high temperature to generate steam, the temperature is lowered to condense water vapor upon which the lid will sealingly engage the rim of the vessel, forming a partial vacuum in the cooking vessel.

US20150313400A1 describes a vacuum low-temperature cooker comprising a housing, an inner pot comprising a basin and a lid, and a heating circulation system comprising a heater, a water pump and connecting pipes. The heater, the water pump and the basin are connected in series through the connecting pipes to construct a closed circulation loop. The basin is equipped with an inlet and an outlet associated with the connecting pipes. The invention makes the temperature inside the inner pot to be constant, such heating circulation loop also makes the water therein to absorb 95% energy emitted by the heater with energy saving. Meanwhile the heater is mounted outside the inner pot, such arrangement makes the inner pot having a maximum space to cook and clean.

US20140348987A1 describes food stuffs that are cooked at precise temperatures, which are optionally below 100° C, in a vessel that is evacuated to exclude air, in which low pressure steam replaces the air. When a sufficient quantity of air is excluded and replaced with water vapor, the temperature of vapor is accurately measured inside the vessel below the lid to control the temperatures within about 1° C. Air is preferably excluded via a controlled heated process for a relatively short period of time at high temperature to generate steam, the temperature is lowered to condense water vapor upon which the lid will sealingly engage the rim of the vessel, forming a partial vacuum in the cooking vessel.

WO2006/088303A1 describes a device for cooking Chinese noodles and a method thereof. The device includes a cooking chamber having a Chinese noodle inlet port; a vacuum pump connected to the cooking chamber for forming vacuum pressure therein; and a pressurized hot water supply means connected to the cooking chamber for supplying pressurized hot water into the cooking chamber. The cooking chamber may comprise a separate Chinese noodle discharge port which is connected to an exhaust chamber for receiving and accommodating the Chinese noodles and hot water, a second discharge port may be disposed at a lower part of the exhaust chamber to discharge the Chinese noodles and hot water, a vapor discharge pipe may be installed at an upper part of the exhaust chamber, and a decompression tank may be connected to the vapor discharge pipe.

US3800778 describes that steam, generated in a steam cooker for foods, is controlled, with respect to the temperature of the steam, over both a range of steam pressure valves in excess of atmospheric pressure and a range of sub atmospheric pressure valves.

EP141720A1 describes an appliance for the vacuum cooking of food, comprising a vacuum-tight cooking chamber connected to a pumping means, wherein it also possesses, located between the cooking chamber and the pumping means, a pressure-drop stabilization member which comprises a vacuum-tight vessel partially filled with water, this vessel being equipped in its upper part with an outlet pipe connected to the pumping means, with, in this sealed vessel, a coil immersed in the water of the vessel, this coil having a first end projecting above the free surface of the water and a second end connected to the cooking chamber by means of a pipeline. US3318708 describes a process for quick cooking legume seeds, wherein the seeds while they are in contact with an aqueous hydrating medium are subjected to a vacuum.

SUMMARY OF THE INVENTION

Certain foods need to be hydrated before consumption, e.g. to soften its hardness or to shorten the cooking time. Examples for such foods are dried beans, whole grain, dried sea food. Further, depending on the food it is necessary to add water, e. g. to allow or promote certain chemical reactions during cooking like hydrolysis or starch gelatinization.

In general, hydration is time consuming. It frequently needs several hours up to the necessity to hydrate the food overnight. With the steadily changing needs of consumers regarding quick cooking times and the desire to be able to prepare a meal conveniently and spontaneously, hydration time is a significant drawback.

Further, hygienic problems can be caused by long hydration times as e. g. bacteria or fungi being attached to the food might grow rendering the food.

Hence, it is an aspect of the invention to provide a method and/or a device for treating food, such as especially a method for hydrating food, which preferably at least partly obviate one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

According to the present invention - amongst others - a method for hydrating food is proposed, comprising the steps of: (a) pressurizing air to a first value in a first closed compartment containing air and the food to be hydrated, the first value being lower than the value of the pressure outside the first closed compartment; and (b) immersing the food into a liquid comprising water for hydrating in the first closed compartment and increasing the pressure inside the first closed compartment from the first value to a second value.

Alternatively, it is possible to separate the step of immersing the food into the liquid from the step of increasing the pressure inside the first closed compartment. In particular, it is possible to perform the immersing step before step a). Thus, an alternative approach of the method for hydrating food comprises the following steps: (A) immersing the food into a liquid comprising water for hydrating in a first closed compartment; (B) pressurizing air to a first value in a first closed compartment containing air and the food to be hydrated, the first value being lower than the value of the pressure outside the first closed compartment; and (C) increasing the pressure inside the first closed compartment from the first value to a second value.

In specific embodiments, in this case at least steps B) and C) are repeated at least once. Step A) might be executed before the (first) execution of step B) or the (first) execution of step C). This alternate approach can be combined with all options disclosed in the following for the method having steps a) and b).

According to embodiments of the present invention steps a) and b) can be repeated at least once.

The invention is in particular suitable for hydrating foods like e. g. rice, in particular white rice and brown rice, beans, in particular back beans, soybeans, red beans, green beans, kidney beans, and lentils. Alternatively or additionally, the food may comprise one or more of corn, maize, buckwheat, etc.. Other, similar types of food, such as other grains or other cereals, may also be possible. In embodiments, the food may comprise legume seeds.

The second value is preferably below the pressure outside the first closed compartment. Alternatively, the second value may be ambient pressure.

Due to steps a) and b) (or steps B) and C)) the properties of the surface and/or the outercoat of the food may be changed. In particular, the permeability of the outer coat of the food, e. g. the taste of the food, for liquids, in particular, water, is increased. Due to these changes the immersion in liquid comprising water in step b) leads to a higher ingress velocity of liquid compared to the same food without executing steps a) and b) (or steps B) and C)). The execution of steps a) and b) (or steps B) and C)) is denominated as "dynamic pressure treatment" in the following.

The liquid ingress leads to a weight gain of the dried food during hydration. Comparing the weight gain obtained by the present invention to a benchmark experiment in which the same amount of food is immersed into water without a previous dynamic pressure treatment (i.e. a conventional soaking process) for a time being identical to the time in which the dynamic pressure treatment has been performed to the food it can be seen that the weight gain according to the present invention may be at least 1.5 times higher than with the conventional soaking.

Hydration according to the present invention may allow a significant weight gain already after a relatively short time of several minutes, i.e. the inclination of a function representing the weight gain over treatment time is very steep in the beginning for the food being dynamic pressure treated. For instance, the hydration of white rice according to the present invention resulted in weight gains of more than 15 wt.% [weight-%] after two minutes only with several cycles of steps a) and b) performed to the sample and more than 20 wt.% after three minutes only. A control experiment in which the same kind of rice was soaked in water for 24 hours revealed a weight gain of about 25 wt.%. The hydration of black beans resulted in a weight gain after several cycles of steps a) and b) according to the present invention of more than 40 wt.% after only two minutes and of more than 60 wt.% after 4 minutes only. The benchmark of a sample of the same kind of black beans soaked for 24 hours in water showed a weight gain of about 90 wt.%.

In particular, the experimental data shows that the invention results in a significant quick weight gain in particular at the beginning of the hydration. This means according to the present invention a significant weight gain and, thus, a significant hydration effect can be reached very quickly allowing a significant acceleration of the hydration process compared to prior art approaches.

According to an embodiment of the invention, the step of pressurizing air to the first value comprises a step of keeping the first value in the first closed compartment during a predeterminable depression time.

The predeterminable depression time is preferably determined based on the kind of food to hydrate, the texture of the food, the taste of the food, the quantity of food to be hydrated, and the overall time available for hydration. The predeterminable depression time is at least 1 second long, preferably at least 10 seconds long. Depression times of 1 second to 30 minutes have been found to be applicable. Preferably, the depression time is in the range of 1 to 5 minutes as the hydration effect has been found to be most effective with depression times in this range. The depression at the first value may in embodiments be executed multiple times.

According to a further embodiment the step of increasing the pressure inside the first closed compartment comprises the step of: (b21) connecting the inside of the first closed compartment with the outside of the first closed compartment.

This allows an easy setup to be used with the invention as the pressure increase up to the second value in step b21) can e. g. be realized by providing and opening a valve to the outside of the first closed compartment. The connection to the outside of the first closed compartment can be established for a predetermined time, e. g. if the second value is lower than the pressure outside the first closed compartment. The connection to the outside might be kept open in particular if the second value is identical to the pressure outside the first closed compartment. The respective valve can be operated manually. Alternatively, the valve can be controlled following a predetermined hydration timetable.

According to a further embodiment the step of immersing the food into the liquid comprises the steps of: (bl 1) providing and operating an elevating mechanism inside the first closed compartment for holding and immersing the food into the liquid originally contained in the first closed compartment.

The application of an elevating mechanism to immerse the food into the liquid is an easy setup for executing step b). The operation of the elevating mechanism can be manually or following a predetermined hydration timetable.

According to a further embodiment the step of increasing the pressure inside the first closed compartment comprises the steps of: (b21 ') providing a second closed compartment containing air and the liquid, and pressurizing the air in the second closed compartment to a third value, the third value being higher than the first value; and (b22') connecting the inside of the first closed compartment with the inside of the second closed compartment and the liquid therein, and conveying at least a part of the liquid from the second closed compartment to the first closed compartment.

The third value and, if necessary, the time during which the first and the second closed compartment are connected, is defined such that after step b22') the pressure within the first closed compartment reaches the second value. The conveying of at least a part of the liquid from the second closed compartment to the first closed compartment is in particular realized by pushing the liquid due to the higher pressure in the second closed compartment to the first closed compartment. Especially, the first closed compartment is connected in step b22') to the part of the second closed compartment which is in step b21 ') filled with the liquid.

It is preferred to provide such an amount of liquid that all of the liquid is conveyed to the first closed compartment. Nevertheless, it is further possible to provide an abundance of liquid and to have only a part of this liquid conveyed from the second closed compartment to the first closed compartment.

According to a further embodiment the step of increasing the pressure inside the first closed compartment comprises the steps of: (b21 ') providing a second open compartment containing the liquid in at least a liquid partition, the second open compartment being opened to the outside of the first closed compartment; and (b22') connecting the inside of the first closed compartment with the liquid partition in the second open compartment, and conveying at least a part of the liquid from the second open compartment to the first closed compartment.

The liquid partition is the part of the second open compartment which is filled with the liquid. As the second open compartment is open to the outside of the first closed compartment and has, thus, ambient pressure, the conveying from the liquid partition of the second open compartment to the first closed compartment is in this embodiment driven by the lower pressure inside the first closed compartment as this first value is below the pressure outside the first closed compartment and, thus, below the pressure in the second open compartment. Therefore, the liquid is sucked from the second open compartment to the first closed compartment. According to a further embodiment the pressure difference between the third value and the first value or the pressure difference between the value of the pressure outside the first closed compartment and the first value is in the range of 70 to 100 kPa

[kilopascal].

A pressure difference (between the first value and the second value) in the range of 70 to 100 kPa (i.e. 0.7 to 1 bar) has been found to lead to a significant quick hydration. In particular, such a pressure difference allows an effective change in the taste of the dried food allowing a quicker take-in of liquid.

According to a further embodiment the step of connecting the inside of the first closed compartment with the inside of the second closed compartment and the liquid therein or the step of connecting the inside of the first closed compartment with the liquid partition of the second opened compartment comprises a step of increasing the first value to the second value over a time duration especially in the range of 0.1 to 2 seconds.

A quick and steep increase of the pressure within the first closed compartment results in an improved take-in of the liquid into the foot. Due to the steep increase of the pressure within the first closed compartment further changes on or of the surface of the food, e.g. of the taste of the food are effectuated that facilitate the take-in of water into the food.

In embodiments, the use of the terms "steps" may not exclude that in between step also other steps may be applied.

Hence, the invention provides in an aspect (and in embodiments) a dynamic pressure treatment method. The dynamic treatment method may also be indicated as

"dynamic treatment process". The term "dynamic pressure" is herein also indicated as "DP". One or more cycles of a reduced pressure (at a first value) and an elevated pressure (at a second value) may be applied to the food. Especially good results may be obtained when the food is first subject to a reduced pressure, to dry the product, and then the food and liquid, especially water, are combined to provide a mixture of the food and the liquid.

For instance, the food may be subjected to vacuum drying, which may the a pressure at the first value. Subsequently, the product may be combined with a liquid, such as water. Thereafter, the pressure may be increased to a second value. In this way, the food is subject to at least one cycle. Alternatively, one or more cycles may be applied to the food, before the liquid and food are combined. Especially, the food and liquid may be combined when the food is a at reduced (first value) pressure. The mixture of the food and liquid may subsequently be subjected to one or more further cycles of a reduced pressure (at the first value) and elevated pressure (at the second value).

For instance, in an aspect the invention also provides a hydrating a food comprising applying a dynamic pressure process to a mixture of the food and a liquid, wherein especially the mixture is obtainable by mixing the food in a (vacuum) dried state with the liquid, wherein the dynamic pressure process comprises one or more cycles of a reduced pressure and an elevated pressure with pressure differences of especially at least 50 kPa.

The herein describe embodiments of the method may especially be useful for grain food, such as brown rice. Grain food, e.g. rice, is a popular staple food in Asia, and is increasingly popular worldwide. In recent years, due to health benefits, whole grain (e.g. brown rice, black bean, and etc.) is recommended as daily intake, however, whole grain is not easy to cook for achieving a well-acceptable sensory attributes. Slow hydration is considered as one of the most important issues in cooking grain foods, esp. in cooking whole grain.

Vacuum drying is a process in which materials are dried in a reduced pressure environment, such as at 50 kPa or lower, which lowers the heat needed for rapid drying. Drying involves reducing the moisture in an object, and is done in environments where the air is drier than the object being dried, which encourages moisture to evaporate out. This is often accomplished with heat to reduce the humidity of the air, but in a vacuum drier, the temperature does not need to be as high, and the drying is faster.

Brown rice is not easy to be dried with normal drying methods due to the presence of whole bran layer, however, in vacuum condition, brown rice is more likely to be dried than in ambient pressure.

The present invention may also solve this problem, optionally in combination with heating. Hence, herein also an alternative method is provided, especially for brown rice and/or black beans, to provide these as palatable cooked products. The application of a dynamic pressure process, especially wherein the food is vacuum dried, subjected to water and then subjected to an elevated pressure, optionally followed by one or more (further) dynamic pressure cycles, en in specific embodiments further followed by a heat treatment ("cooking") may provide well palatable products in a relative short time, much shorter than via prior art methods.

Therefore, in embodiments mixture of the food and the liquid may be subjected to a heating during the process of varying the pressure, especially the dynamical pressure process, and/or may be subject to heating after this process of varying the pressure especially the dynamical pressure process. Therefore, in embodiments the method may further optionally comprise heating the mixture to a temperature of at least 60°C, especially at least 80°C (during and/or after the dynamic pressure process).

During the drying stage, the moisture (water) may be reduced by at least 10%, such as at least 20%. For instance, the original moisture content in brown rice is about 12%, which can be reduced by drying to about 7-8 %. Therefore, in embodiments the moisture in brown rice may be reduced by at least 20%>, such as at least 40%> by. (i.e. only 60%> of original water retained).

Hence, in an aspect the invention provides a method for hydrating food, comprising the steps of: (a) pressurizing air to a first value (VI; herein also indicated as "first pressure value") in a first closed compartment containing air and the food to be hydrated, the first value (VI) being lower than the value (V0) of the pressure outside the first closed compartment; (b) immersing the food into a liquid comprising water for hydrating in the first closed compartment to provide a mixture of the food and the liquid, and increasing the pressure inside the first closed compartment from the first value (VI) to a second value (V2; herein also indicated as "second pressure value"); and (optionally) (c) heating the mixture to a temperature of at least 60°C, such as especially at least 80°C.

The method for hydrating food including also a heating step may herein also be indicated as a "method of cooking" or a "cooking method", or "method of cooking a food", and similar indications.

With such method a palatable food, such as a palatable brown rice, may be obtained in a time substantially smaller than with conventional methods.

Further, it appears that it is especially useful to vacuum dry the food to provide the food in the dried state, followed by a mixing the food in the dried state with the liquid to provide the mixture for applying the dynamic pressure process. Therefore, in embodiments the method comprises vacuum drying the food to provide the food in a dried state before immersing the food in the liquid. Herein, the term vacuum may especially refer to a pressure of at maximum 50 kPa. Hence, combining the food and the liquid may especially imply immersing the food product in the liquid.

In embodiments, the stage wherein the product is not yet combined with the liquid, may be a drying step at a reduced pressure (vacuum drying) and/or at an elevated temperature. Especially, a combination of vacuum drying and heating may be applied. The heating may be an elevation to a temperature selected from the range of 60-100°C, though lower or higher temperatures may also be possible. As indicated above, the vacuum may be at maximum 50 kPa, such as selected from the range of about 5-30 kPa. The total treatment time at a reduced pressure and/or at an elevated temperature, such as at a reduced pressure optionally in combination with (at least part of the time at reduced pressure) a heating, may e.g. be selected from the range of at least 1 minute, such as in the range of 2-60 minutes, such as 5-20 minutes. During this treatment time, one or more cycles of reduced and elevated pressure may be executed.

Especially, the total time at the reduced pressure, i.e. at the first value(s) may be at least about 2 minutes, such as at least about 5 minutes. Hence, the total

(predeterminable) depression time or accumulated (predeterminable) depression time may be at least about 2 minutes, such as at least about 10 minutes.

Especially, the increase in pressure to the second value may be relatively quick, such as within about five seconds, like even within about two seconds. Therefore, in embodiments the step of increasing the first value VI to the second value V2 involves a time duration in the range of 0.1 to 2 seconds. Even shorter times may also be possible. The decrease in pressure to the first value may also be relatively quick, such as within about 20 seconds, like even within about 10 seconds.

After the drying stage, which includes one or more of subjecting the food to a reduced pressure and a heating, the food is combined with the liquid, such as water. Then, the combination may be subject to an increase in pressure to the second value. Optionally, one or more further cycles of reduced and elevated pressure may be applied after the combination of the food and the liquid. Of course, if desired the drying of the food may also include a plurality of cycles of reduced and elevated pressure (see also above); this embodiment is however herein not further elucidated.

Therefore, in embodiments the method comprises a plurality of n cycles of a reduced pressure with first value (VI) and an elevated pressure with second value (V2), wherein 2<n<100. Anyhow, the food is subject to one cycle, wherein it is started with a product not in combination with the liquid, and after having the food subject to the reduced pressure, the food is combined with the liquid, such as by immersing in the liquid. Especially, the food may be combined with the liquid under reduced pressure. However, in alternative embodiments the food is combined with the liquid at an elevated pressure, such as at ambient pressure.

In specific embodiments, the pressure differences between the first value (VI) and second value (V2) is at least 50 kPa. As indicated above, e.g. a pressure difference in the range of 70 to 100 kPa (i.e. 0.7 to 1 bar) has been found to lead to a significant quick hydration. In particular, such a pressure difference allows an effective change in the taste of the dried food allowing a quicker take-in of liquid.

In further specific embodiments, the first value (VI) is at maximum 50 kPa. In yet further specific embodiments, the second value (V2) is atmospheric pressure; the first value (VI) may thus be at maximum 50 kPa. Using atmospheric pressure as the second value is a convenient choice and may allow a quick increase of the pressure (by opening one or more valves to the ambient).

Note that not necessary VI is always the same in each cycle (when a plurality of cycles is applied). The pressure value VI (and/or value V2) may differ per cycle. The value(s) may depend upon the time chosen for the specific pressure value. For instance, the time at the first value may be selected from 1-300 seconds, such as 10-60 seconds.

The value may also depend upon the temperature, which may be ambient, but which may in embodiments - as indicated above - also be elevated, such as at least 60°C (during the dynamic processing cycle(s)). Especially, the first pressure value (and temperature) is chosen such that the liquid is boiling (during at least part of the time the mixture is at the first value).

Process parameters like the number of cycles, the pressure times, the time of increasing the pressure, the temperature, etc., may be chosen according to a predetermined heating program and/or pressure program for the food. Alternatively or additionally, such parameters may be controlled as function of a sensor signal, such as from a temperature sensor, a pressure sensor, a sensor configured to sense the type and/or processing stage of the food.

As indicated above, a heating stage after the cycle of reduced and elevated pressure may also be included, especially when the food has to be cooked, such as to provided cooked brown rice or cooked black beans. For instance, the temperature may be increased to at least 60°C, such as at least 80°C, such as for a time period of at least 1 minute, like selected from the range of 1-120 minutes, especially 5-90 minutes. Such temperature increase may be defined according to a temperature program for the food, especially a program with a predetermined heating and pressure program for foods.

For instance, such program may include a multi-stage heating process, wherein e.g. during a (predetermined) period the temperature is maintained in the range of 60-80°C, and in a (predetermined) period the temperature is maintained in the range of at least 90°C, such as at least 95°C.

Therefore, in embodiments the method may comprises heating the mixture to a temperature of at least 90°C, such as especially at least 95°C, such as in the range of 95- 100°C (especially at atmospheric pressure).

After a final heating (step) the food may be cooled down. This may a cooling down without additional action, i.e. letting the food cool down. Optionally, the cooling down may be a forced cooling down by cooling the food with cool air. In embodiments, the cooling down may include one or more cycles of a reduced pressure (at a first value) and an elevated pressure (at a second value). These values may differ from the values used during the dehydration and/or cooking stage. In embodiments, the mixture of the food and liquid may be cooled down. In other embodiments, before cooling, or during cooling, especially before cooling, at least part of the liquid, especially essentially all the (remaining) liquid, may be removed from the compartment. Especially, the end product is a hydrated (cooked) food.

As indicated above, the food may especially comprise one or more of brown rice and black bean. The method (and device) may especially be used for such foods. In specific embodiments, the liquid comprises water. In yet other embodiment, the liquid comprises one or more of water, milk, a milk replacer, and an alcohol containing edible liquid. The term "edible liquid" especially refers to a potable or drinkable liquid, i.e. a liquid intended for human consumption.

As indicated above, the invention also provides a device for the pressure treatment, and in further embodiments also a device for a pressure and temperature treatment. Such device may especially be configured to execute the herein described method for hydrating (or cooking) the food. Hence, for instance in an aspect a device for treating a food is proposed, wherein the device comprises a compartment for containing a mixture of the food and a liquid, and a pressurizing system for controlling the pressure in the compartment. Especially, the pressurizing system may at least configured to provide one or more cycles of a reduced pressure and an elevated pressure in the compartment with pressure differences of especially at least 50 kPa. Alternatively or additionally (to the pressurizing system), the device may comprise a heater for heating a content of the compartment to a temperature of at least 80°C. Yet further, such device may comprise a control system configured to control the heater and/or the pressurizing system according to a predetermined heating and/or pressure program for the food.

Hence, the invention also provides a device for hydrating the food wherein the device is configured to subject the food to a reduced pressure with value VI , combine with a liquid, and subject the mixture to an elevated pressure with a value V2, such as ambient pressure.

Therefore, according to a further aspect of the present invention a device for hydrating food is proposed, comprising: (i) a first closed compartment for containing air and the food to be hydrated in a liquid comprising water; (ii) a first system for pressurizing the air in the first closed compartment to a first value, the first value being lower than the value of the pressure outside the first closed compartment; and (iii) a second system for immersing the food into the liquid in the first closed compartment and increasing the pressure inside the first closed compartment from the first value to a second value. With the second system, it may amongst others be possible to provide a mixture of the food and the liquid.

The device according to the present invention is preferably adapted and determined to perform the method according to the present invention. The first system preferably includes a source of underpressure or can be connected to a source of

underpressure for reducing the pressure within the first closed compartment to the first value. The second system preferably includes a pressure reservoir of pressure being higher than the first value or can be connected to a reservoir of pressure being higher than the first value. This can e.g. be the surroundings of the first closed compartment having an ambient pressure above the first value. The source of underpressure or overpressure and the pressure reservoir can be connected to other compartments, like e.g. a second open compartment or a second closed compartment as well to pressurize this compartment to a required value.

The first closed compartment is sealable from its environment e.g. by providing respective seals. The first and second system both comprise at least one valve that allows to adapt the pressure within the first closed compartment and to seal the first closed compartment from its surroundings after the pressure within this first closed compartment has been set to the first value or second value. The first and second system can share the same valve. The at least one valve can be operated manually or automatically following a predetermined hydration timetable which can e.g. be predetermined based on the kind of food to hydrate, the amount of food to be hydrated and/or the available time to hydrate the food. According to an improvement the liquid is originally contained in the first closed compartment; the second system comprises an elevating mechanism inside the first closed compartment for holding and immersing the food into the liquid; the second system further comprises a first valve for connecting the inside of the first closed compartment with the outside of the first closed compartment.

This means the first closed compartment is designed to be provided with the liquid before the first closed compartment is pressurized, e. g. according to step a) or B) as discussed above e. g. by providing a liquid partition in which liquid can be provided. The elevating mechanism is e.g. a mechanically operable apparatus by which the food can be raised and lowered with respect to the liquid partition.

According to a further embodiment, the second system comprises a second closed compartment containing air and the liquid, having a liquid partition for providing the liquid and the air in the second closed compartment is pressurized to a third value being higher than the first value; the second system further comprises a second valve for connecting the inside of the first closed compartment with the liquid partition of the second closed compartment and the liquid therein.

This means that the second closed compartment may be adapted to provide beside air the liquid as well, e.g. by providing a liquid partition for providing a reservoir of the liquid within the second closed compartment. The second closed compartment is equipped such that it can be pressurized to a third value being higher than the first value. This third value can be lower than the ambient pressure outside the second closed compartment or higher than this ambient pressure. The liquid partition e.g. can be the lower partition of the second closed compartment. It can be separated from the remainder of the second closed compartment by dividers, e.g. by walls. It is preferred that the liquid partition is a partition of the second closed compartment, e.g. the lower part of the second closed compartment without having further dividers. Preferably, the second valve is provided at the lowermost point of the liquid partition allowing conveying the liquid from the second closed compartment to the first closed compartment independent of the amount of liquid provided in the liquid partition i.e. independent of the fluid level in the liquid partition.

This embodiment allows to convey the liquid from the second closed partition to the first closed partition by pressurizing the air in the second closed compartment to the third value being higher than the first value and by then opening the second valve to push the liquid by the pressure difference (i.e. by the overpressure relative to the first value in the first closed compartment) from the second closed compartment to the first closed compartment,. According to a further embodiment the second system comprises a second open compartment comprising a liquid partition containing the liquid, the second open compartment being open to the outside of the first closed compartment; the second system further comprises a third valve for connecting the inside of the first closed compartment with the liquid partition of the second open compartment. This embodiment may allow reducing the necessary efforts as the overpressure relative to the first value in the first closed compartment is easily provided based on the ambient pressure of the surroundings outside the first closed compartment via the second open compartment. The third valve can be actuated manually or automatically under following a predetermined hydration timetable.

According to a further embodiment the pressure difference between the third value and the first value or the pressure difference between the value of the pressure outside the first closed compartment and the first value is adapted in the range of 70 to 100 kPa. This means the device may be adapted to be controlled to create a respective pressure difference in the range of 70 to 100 kPa.

According to a further embodiment the second system is adapted to increase the pressure inside the first closed compartment from the first value to the second value over a time duration in the range of 0.1 to 2 seconds.

A quick and steep increase of the pressure within the first closed compartment results in an improved take-in of the liquid into the foot. Due to the steep increase of the pressure within the first closed compartment further changes on or of the surface of the food, e.g. of the taste of the food are effectuated that facilitate the take-in of water into the food. The short time durations can preferably be realized by utilizing valves allowing a quick operation.

As indicated above, the method may also include a heating step. Therefore, especially the device may further comprise a heater for heating (in a controlling mode) a content of the compartment, such as to a temperature of at least 60°C, like at least 80°C. Such heater may be used to heat the contents of the compartment during drying. Such heater may alternatively or additionally also be used to heat the contents after the one or more cycles of reduced pressure and elevated pressure. Such heater may alternatively or additionally also be used to heat the contents during at least part of the time of one or more cycles of reduced pressure and elevated pressure. Therefore, the device may further comprise a heater for heating (in a controlling mode) a content of the compartment to a temperature of at least 80°C. In specific embodiments, the heater may be configured to heat (in a controlling mode) a mixture of the food and the liquid to a temperature of at least 90 °C, such as at least 95°C. Therefore, in embodiments the device may comprise a heater for heating (in a controlling mode) the content of the compartment to a temperature of at least 95°C. The phrase

"configured to heat a mixture of the food and the liquid to a temperature of at least 95°C" and similar phrases may also refer to a heater including or allowing a heating program wherein lower or higher temperatures may be achieved. At least however, such heater is able to heat to at least the indicated temperature. Especially, this may refer to a heater including a control system that includes at least one controlling mode wherein the contents (such as the mixture within the compartment during use of the device) is heated to the indicated temperature (such as at least 60°C, or at least 80°C, or at least 95°C).

The term "heater" may also refer to a plurality of (different) heaters.

As indicated above, the device may especially be configured to vacuum dry (in a controlling mode) the food to provide the food in a dried state before immersing the food in the liquid. The drying may include one or more of heating and subjecting to a reduced pressure. Immersing may in embodiments be executed with an elevating mechanism inside the compartment for holding and immersing the food into the liquid. Such elevating mechanism may in embodiments be comprised by the second system.

Herein, the terms "first system" and "second system" are especially used to indicate several abilities. These terms may also refer to a system including such abilities, such as a system including a pump configured to reduce the pressure to a first value or increase the pressure to a second value, dependent upon the desired action (or programmed action).

In embodiments, the device is especially configured (in a controlling mode) to increase (the pressure) from the first value (VI) to the second value (V2) over a time duration in the range of within about 5 seconds, such as in the range of up to 2 second, like in the range of 0.1 to 2 seconds. In further specific embodiments, (in a controlling mode) the first value (VI) is at maximum 50 kPa, and the second value (V2) is atmospheric pressure.

In embodiments, the device is especially configured (in a controlling mode) to decrease (the pressure) from the second value (VI) to the second value (V2) over a time duration in the range of within about 20 seconds, such as in the range of up to 10 second, like in the range of 1 to 10 seconds.

As indicated above, after one or more cycles of the dynamic pressure process, the mixture may be subjected to a heating (cooking). Hence, in embodiments the device is configured to heat (in a controlling mode) the mixture of the food and the liquid to a temperature of at least 90°C, especially at least 95°C. Further, as indicated above in specific embodiments the device is configured to execute (in a controlling mode) a plurality of n cycles of a reduced pressure with first value (VI) and an elevated pressure with second value (V2), with pressure differences between the first value (VI) and second value (V2) of at least 50 kPa, wherein 2<n<100.

The heater and system (such as the first and/or second system) may be controlled via a control system. Therefore, in embodiments the device may further comprise a control system configured to control the heater, the first system, and the second system according to a predetermined heating and/or pressure program for the food. The

predetermined heating and/or pressure program may include modes for treating beans or modes for treating rice; it may also include modes to provide different degrees of doneness of such foods.

The term "controlling" and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein

"controlling" and similar terms may e.g. refer to imposing behavior to the element

(determining the behavior or supervising the running of an element), etc., such as e.g.

measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term "controlling" and similar terms may additionally include monitoring. Hence, the term "controlling" and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element.

The controlling of the element can be done with a control system. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and/or wireless control. The term "control system" may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems.

The term "controlling mode" especially indicates a selectable (or selected) set of conditions that are imposed to the device to provide a specific food or a specific degree of doneness of such food. Hence, in embodiments there may be a plurality of different controlling modes.

According to a further aspect a kitchen appliance for preparing food is proposed, comprising a device according to the present invention, the kitchen appliance being taken among multi-cooker and cold-cooker. The kitchen appliance may also include a rice- cooker. Therefore, the invention also provides a kitchen being taken among a multi-cooker, a rice cooker, and a cold-cooker. The term "closed compartment" and similar terms may refer to a compartment or arrangement of a compartment that can be opened and that can be closed. The closed state may especially refer to a stage during at least part of the operation time. Hence, the terms "closed compartment" and "compartment" may be used for the same compartment(s).

As indicated above, the device may be used to execute the method such as described herein. However, the method may also be executed with other devices. Hence, in yet a further aspect the invention also provides a computer program product, optionally implemented on a record carrier (storage medium), which when run on a computer executes the method as described herein (see below) with a device as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Fig. 1 depicts schematically an example of a device for hydrating food;

Fig. 2 depicts schematically a further example for a device for hydrating food;

Fig. 3 depicts schematically a further example for a device for hydrating food;

Fig. 4 depicts schematically a further example for a device for hydrating food; Fig. 5 depicts schematically an example of a kitchen appliance including a device for hydrating food;

Fig. 6 schematically depicts an embodiment of a possible dynamic process treatment process, with on the x-axis the treatment time in seconds, and on the y-axis the pressure p (in kPa);

Fig. 7 schematically depicts two cycles of a multiple cycle process with on the x-axis the treatment time in seconds, and on the y-axis the pressure p (in kPa);

Fig. 8 schematically depicts a further example of a device; and

Fig. 9 schematically depicts a non-limiting example of a possible treatment method.

The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 schematically depicts a device 100 for hydrating food 160. The device 100 includes a first closed compartment 110 for containing air and the food 160. The food is to be hydrated in a liquid 190 comprising water. Further, the first device 100 includes a first system 150 including a vacuum pump 151 for generating an underpressure relative to the pressure of the outside 300 of the first closed compartment 110. The vacuum pump 151 is connected to the first closed compartment 110 via first vacuum tubing 152. The first closed compartment 110 is closable and sealable to the outside 300 such that a defined pressure inside the first closed compartment 110 can be generated. In use, in particular performing step a) or B) according to the present invention the inside the first closed compartment 110 is pressurized to a first value VI via the first system 150. The pressure inside the first closed compartment 110 is monitored using a first pressure sensor 171.

The device 100 further includes a second system 180 for immersing the food

160 into the liquid and increasing the pressure inside the first closed compartment 110 from the first value VI to a second value V2. In the present first example the second system 180 comprises a second closed compartment 112 having a liquid partition 200 being filled with the liquid 190. The second system 180 further includes the vacuum pump 151, second vacuum tubing 153 connecting the vacuum pump 151 to the second closed compartment 112. The second closed compartment 112 is sealable to the outside 300 and is in use closed. In use via the second system 180 and its vacuum pump 151 the second closed compartment 112 can be pressurized such that when connecting the liquid partition 200 of the second closed compartment 112 via the second valve 140 that due to the first value VI and the pressure in the second closed compartment 112 at least a part of the liquid 190 is conveyed from the second closed compartment 112 to the first closed compartment 110 to immerse the food 160 in the liquid 190 in the first closed compartment. Temperature sensors 170 can be arranged in the first closed compartment 110, the second closed compartment and/or the liquid partition 190 to monitor the temperature of the air in the first closed compartment 110 and/or the second closed compartment 112 and/or the liquid 190.

The second valve 140, the vacuum pump 151, the first pressure sensor 171 and the at least one temperature sensor 170 are connected to a controller 130 which controls the operation of at least one of these elements. The controller 130 can execute a predetermined hydration timetable to accurately hydrate the food 160 in the first closed compartment 110. Instead of the term "controller" herein also the term "control system" is applied.

Fig. 2 depicts schematically a further example of a device 100 for hydrating food 160. This device comprises a first closed compartment 110 which is closable and connectable to the outside 300 or to the vacuum pump (not shown here) via a first valve 139. The vacuum pump can be connected to the first closed compartment 110 via another opening or valve in the first closed compartment 110.

The device 100 further comprises an elevating mechanism 181 which is in this example a mechanical lift system. By this elevating mechanism 181 the food 160 can be immersed in the liquid 190 being provided in this example from the beginning in the first closed compartment. The elevating mechanism 181 is shown in two positions, one above the liquid 190 and one immersed in the liquid 190. As the arrow 182 symbolizes by operating the elevating mechanism 181 it can be moved between these two positions in the specified direction.

Via the first system including the vacuum pump (not shown here) being connected to the first valve 139 the first closed compartment 110 is in use pressurized to a first value VI being lower than the pressure outside the first close compartment 110 with the emerging mechanism 181 in its position above the liquid 190. Thereafter, the food 160 is immersed into the liquid 190 by moving the emerging mechanism 181 into the immersed position while opening the first valve 139, thereby connecting the inside of the first closed compartment 110 to the outside 300 to increase the pressure inside the first closed compartment 110. Depending on the time in which the first valve 139 is opened to connect the inside of the first closed compartment 110 with the outside 300 the pressure within will increase until finally reaching the value V0 of the pressure outside the first closed compartment 110, therefore allowing to adjust the pressure within the first closed

compartment 110 to a value between the first value VI and the value V0 of the pressure outside the first closed compartment.

Fig. 3 depicts schematically a third example of a device 100 including the first closed compartment 110 and a second closed compartment 112 as in the first example. Both the first closed compartment 110 and the second closed compartment 112 are connectable to the outside 300 via the first valve 139 in case of the first closed compartment 110 and via a third valve 141 in the case of the first closed compartment 112 but can be sealed from the outside 300 as well to maintain a first value VI of the pressure in the first closed

compartment 110 and a third value V3 in the second closed compartment 1 12. Both compartments 110, 112 are pressurized using a vacuum pump (not shown) which is connectable to the compartments 110, 112. The third value V3 is higher than the first value VI . During pressurizing the compartments 110, 112 the compartments are not in fluid connection. The second closed compartment 112 includes the liquid 190 in the liquid partition 200 of the second closed compartment 112. This liquid partition 200 is connected to the first closed compartment 110 via a connection 220 including the second valve 140. While pressurizing the first closed compartment 110 and the second closed compartment 112 to the desired pressure values the second valve 140 is closed. After the pressure in the first closed compartment 110 has reached the first value VI and the pressure in the second closed compartment 112 has reached the third value V3 and a predetermined depression time, preferably in the range of 1 to 5 minutes, is elapsed the second valve 140 is open. Due to the higher pressure in the second closed compartment 112 the liquid 190 is at least in part pushed to the first closed compartment 110 to immerse the food 160 as is shown by the arrow 221 and the liquid 190 shown in a dashed line in the first closed compartment 110. The pressure in the first closed compartment 110 reaches the second value V2 due to the connection between the first closed compartment 110 and the second closed compartment 112.

In this example as well the first system (not shown) for pressurizing the air in the first closed compartment 110 to the first value VI comprises a source of underpressure like a vacuum pump. The second system 180 includes beside a source of underpressure or overpressure, e.g. a vacuum pump (not shown), the second closed compartment 112, the connection 220 and the second valve 140.

Reference 175 indicates the combination (or mixture) of the liquid 190 and the food 160.

Fig. 4 depicts schematically a fourth example of the device 100 for hydrating food 160. In contrast to the third example as depicted in Fig. 3 the device 100 comprises a second open compartment 114 which is not closable towards the outside 300 of the first closed compartment but which is constantly open. This means within the second open compartment 114 the pressure is always identical to the value V0 of the pressure outside the first closed compartment 110. The liquid partition 200 of the second open compartment 114 is connected to the inside of the first closed compartment 110 via a connection 220 including a third valve 141.

After the pressure within the first closed compartment 110 has been brought to the first value VI and the predetermined depression time has elapsed the third valve 141 is opened and due to the underpressure within the first closed compartment 110 relative to the second open compartment 114 the liquid 190 is conveyed from the liquid partition 200 of the second open compartment 114 to the first closed compartment 110 to immerse the food 160 in the liquid. In this example the first system comprises a vacuum pump or another source of underpressure connectable to the first closed compartment 110 to reduce the pressure to the first value VI . The second system 180 comprises the second open compartment 114, the connection 220 and the third valve 141.

Fig. 5 very schematically depicts a kitchen appliance 250, like a multi-cooker or a cold-cooker, including a device 100 for hydrating food as discussed in this document.

This dynamic pressure can speed up the hydration to save effort and time for consumers, which can also naturally increase the water absorption of food without any mechanism damage.

Fig. 6 schematically depicts an embodiment of a possible dynamic process treatment process, with on the x-axis the treatment time in second, and on the y-axis the pressure (in kPa). By way of example, 15 cycles are shown. However, more or less cycles, smaller or larger pressure differences, smaller or longer times of the reduced pressure, and/or smaller or longer times of the elevated pressure may be possible.

In general, the process of DP treatment includes several steps: (1) prepare materials, (2) seal the food container, (3) vacuum the container and keep it under vacuum status for some time, (4) break the vacuum status of container quickly, (5) if necessary, repeat step 3 and 4 as required, (6) complete DP treatment, and enter into next steps of food processing. During the DP process, pressure change can introduce several effects on treated materials: (1) Vacuum effect, (2) 0-0.1 MPa pressure (force) effect, (3) shear force and mixing effects due to quick vacuum breakdown.

Fig. 7 schematically depicts two cycles of a multiple cycle process in more detail. Reference t21 indicates the time used to reduce the pressure from the elevated pressure, at second value V2 to the reduced pressure at the first value VI . This time may e.g. be at maximum 20 seconds, like at maximum 10 seconds; however, this time may also be longer. Especially, the time used to increase the pressure, indicated with reference tl2, is short, such as at maximum 5 seconds, like at maximum 2 seconds. Reference tl indicates the time at the reduce pressure value VI; this time is herein also indicated as "predeterminable depression time". The total time at tl during the process of reducing and increasing the pressure (e.g. 15x tl in Fig. 6) may especially be selected from the range of at least 1 minute, such as in the range of 2-60 minutes, such as 5-20 minutes.

Based on empirical values, each vacuum level corresponds to determined boiling temperature, e.g. the boiling temperatures of water at 0.01, 0.03, 0.2 and 1 atm are 6.97, 24.08, 60.06 and 99.61°C, respectively. At lower pressure, the boiling temperature of water is lower, therefore, water is easy to be evaporated. For rice itself, lower pressure can remove more moisture, while for rice and water, lower pressure can generate more evaporation.

Hence, especially during each reduced pressure stage the liquid boils. As indicated above, during the dynamic process, it may also be possible to heat the contents of the container with a heater.

Brown rice may generally need longer cooking times than white rice due to the presence of bran layer, which will slow the whole cooking process. If within determined cooking time, slow cooking process inevitably affect the textural qualities of cooked brown rice in a negative way. Cooking methods for brown rice may amongst others have the problems of a slow hydratation rate and/or an un-even heating.

Hydration of starch is one of the most important steps in rice cooking, and is considered as the rate-limiting step in whole rice cooking process. At the same time, if rice hydration is not enough, the textural qualities of cooked rice will be lower. The slow hydration of starch in brown rice are results from (a) bran layer blocks the water from penetrating into inner part, (b) the compact structure of starch granule, (c) air on the food surface cause a low surface tension, and water cannot wet a low surface tension surface, (d) air bubbles that are trapped in rice pores are even more difficult to be replaced by water in ambient soaking.

Even heating during rice cooking can deliver a better textural qualities of cooked rice. Most current rice cooking methods or rice cookers, especially for brown rice cooking, has a major disadvantage: remain the air in rice during soaking and following cooking processes, since the heat transfer efficiency of air is much lower than water, therefore, the presence of air causes uneven heating of the whole rice, resulting in relatively lower texture qualities of cooked rice.

The technology proposed herein can overcome above mentioned problems.

The combination of vacuum drying and DP soaking has several benefits: (1) vacuum drying can accelerate the moisture loss process, in which the water molecular are easier to be transformed to water vapor, this phase transformation can increase internal pressure due to volume increase, the elevated pressure can loosen the compact structure of starch granule, and open some holes and cracks in brown rice bran layer; What's more, for the water in rice that does not transform to vapor, it will move closely to outer layer, then move out for drying, this water molecular movement can also help open holes and cracks in starch granule and bran layer. The change in brown rice structure increases the air surface tension when soaked in liquid, but potentially beneficial for following soaking treatment; (2) after vacuum drying, DP soaking is applied to improve soaking effect. Low pressure causes the air bubbles to release from rice, and pressure release will increase water absorption extent due to pressure- pushing the water to replace (air bubble) spaces and enter into the rice granule through generated holes and cracks. Low pressure DP treatment will add the kinetic effect to faster release the air from the rice to be replaced by water.

With improved soaking process, more water is distributed inside brown rice, therefore, even heating can be achieved during following heating process.

Amongst others, this invention provides a new cooking method to cook e.g. rice, esp. for brown rice. In embodiments, the main steps may be: (1) Prepare suitable food, such as brown rice in cooking chamber; (2) Vacuum drying the food, such as brown rice, in the condition of: temperature ranges from 60 to 100°C, vacuum level ranges from 30 kPa to 5 kPa, and treatment time ranges from 5 to 20 min; (3) After vacuum drying, add suitable water into cooking chamber for DP treatment, and heating the mixture of the food, such as rice and water into predetermined temperature, which ranges from ambient temperature to 60°C; (4) DP treatment conditions. Total DP treatment includes 1-100 cycles. Each cycle includes four steps: vacuuming, vacuum maintaining, quick pressure releasing (1-5 s), and ambient pressure maintaining. Time allocation for the rest steps can be any types. And for each DP cycle: pressure ranges from 50 kPa to 5 kPa, time ranges from 10 s to 60 s; (5) Then, heating up the mixture of the food, such as brown rice, and water to 60~80°C and keep for predetermined time (1-30 min); (6) Keep on heating up the mixture of the food, such as brown rice and water to 95~100°C and keep for predetermined time (10-40 min); and (7) Completion of the whole cooking process. This cooking method or food treatment method may also be applied for other foods. Further, this cooking method or treatment method may also be executed with other process parameters.

Fig. 8 schematically depicts a further example of a device 100, including a compartment 110, a (optionally) heater 210. Reference 135 indicates an optional sensor, such as e.g. a sensor to control which type of food 160 is available, or a temperature sensor, etc.. The control system 130 may control the process parameters of the method in dependence of the sensor signal of the sensor 135.

Further, Fig. 9 schematically depicts a non-limiting example of a possible treatment method. Here, by way of example there are 5 cycles of reduced and elevated pressure, during which the temperature is also increased. After the cycles, the temperature is further increased. Then, yet a further step of reduced pressure is applied. Examples were executed. In a control 200 g brown rice and 400 g water were treated using a rice cooker. A brown rice cooking model was selected with a total cooking time is 1 h 20 min. In a method of the invention, 200 g brown rice was put in a cooking chamber, the contents were vacuum dried for 10 min, with a vacuum level 10 kPa at a temperature at 85°C. Then, 400 g water was added into cooking chamber, and the mixture was heated to 40°C. Then, the DP treatment was performed with a vacuum level at 15 kPa. The treatment lasted in total 10 minutes, with and 0.5 min for each cycle, including 25 seconds vacuuming (fast pressure decreasing -10 s, and low pressure maintaining ~ 15), and 5 seconds vacuum breaking (pressure back to 1 atm and at 1 atm). After the DP treatment, the mixture was heated to 60°C, and kept at this temperature for 10 minutes. Thereafter, the mixture was heated from 60°C to 100°C, and kept at this temperature for 25 minutes. The cooking process was completed; the total time was 60-65 minutes. Optionally, the cooling time may be reduced by e.g. a vacuum cooling (including one or more cycles of a reduced pressure and an elevated pressure). The textural qualities of cooked brown rice were evaluated to compare the advantages of this invention over control cooked brown rice. The results indicated that cooking method described herein can significantly decrease the hardness of cooked brown rice by 22.6% (relative to the control), and increase the stickiness of cooked brown rice by 25% (relative to the control). The decrease in hardness and the increase in stickiness reflect the improvement in the sensory attributes of cooked brown rice. Hence, the stickiness and hardness behavior improved, while the total processing time was substantially smaller.

The term "substantially" herein, such as in "substantially consists", will be understood by the person skilled in the art. The term "substantially" may also include embodiments with "entirely", "completely", "all", etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term "substantially" may also relate to 90%> or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term "comprise" includes also

embodiments wherein the term "comprises" means "consists of. The term "and/or" especially relates to one or more of the items mentioned before and after "and/or". For instance, a phrase "item 1 and/or item 2" and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species". Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The devices herein are amongst others described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation or devices in operation.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to". The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The invention further applies to a device comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications. LIST OF REFERENCE SYMBOLS

110 first closed compartment

112 second closed compartment

114 second open compartment

130 controller

135 sensor

139 first valve

140 second valve

141 third valve

150 first system

151 vacuum pump

152 first vacuum tubing

160 food to be hydrated

170 temperature sensor

171 first pressure sensor

180 second system

181 elevating mechanism

182 arrow

190 liquid

200 liquid partition

210 heater

220 connection

221 arrow

250 kitchen appliance

300 outside

V0 value of the pressure outside the first closed compartment

VI first value of pressure in the first closed compartment V2 second value of pressure in the first closed compartment

V3 third value of pressure in the second closed compartment