Abstract: A conveyor oven for cooking food products using infra-red radiation is described. The oven uses upper and lower etched foil heaters which are disposed above and below the upper flight of a conveyor belt passing therethrough. The oven also includes a controller for governing the speed of the belt, the time of exposure to infra-red radiation, and a range of radiation wavelength between about 4 and 5 microns for cooking the food in the oven.

Abstract: An apparatus for pasteurizing and precooking pizza bases includes a conveyor belt having an upstream end and a downstream end, a plurality of vitroceramic plates attached to the conveyor belt, and a microwave tunnel positioned for heating vitroceramic plates conveyed through the microwave tunnel. Downstream of the microwave tunnel, pizza bases are delivered to the heated vitro- ceramic plates and they transported in contact with the heated plates to pasteurize and precook the pizza bases.

Abstract: An electric grilling appliance includes a pair of infrared radiation emitting heaters disposed within a housing on opposite sides of a food holder. The food holder includes a pair of metal food holder plates of a size and configuration to directly contact, on their inner surfaces, substantially the complete outer surface of the food article to be grilled. The outer surfaces of the metal food holder plates are blackened to absorb the infrared radiation emitted by the heaters. Springs urging the metal food holder plates towards each other into firm contact with the food article to be grilled.

Abstract: A food preparation oven includes a cooking chamber (1) in which a device (12) is provided for generating heat waves and for directing them in a suitably concentrated manner onto the surfaces (6, 7, 8, 9, 10,11) of the walls of the chamber (1); the device (12) is removably arranged in the cooking chamber (1) and is mobile therein so as to direct the heat waves onto the entire surface of the walls, the concentrated waves scanning the surfaces (6, 7, 8, 9, 10, 11) but covering only portions of them at any given time, creating only in and around these portions a high temperature which results in the pyrolysis of the impurities which have been deposited on the surfaces (6, 7, 8, 9, 10, 11) during the use of the oven. The heat waves can also be used for food preparation.

Abstract: A microwave tunnel oven receives a series of packages each comprising a container and a load in the container to be heated by microwave energy. The oven has a conveyor with a series of carriers each for receiving one of the packages and conveying it through the oven. The improvement comprises modifying the microwave field in the load during its irradiation in the oven in a manner to generate higher order modes of microwave energy in the load to enhance the uniformity of heating throughout the load. The structure for achieving the field modification is divided into two parts, one part being formed on the conveyor and the other part being formed either on the package or on a subsidiary conveyor that extends parallel to the main conveyor.

Abstract: An apparatus for processing food which includes an insulated container having a conductive lining. A negative electron generator is coupled to the conductive lining for transmitting negative electrons to the lining thus creating a condition of high humidity inside the container.

Abstract: A frozen food is thawed by irradiating the frozen food with far infrared rays while supplying cold air to the frozen food to maintain the surface temperature thereof at a level not higher than 10.degree. C. Prior to the far infrared ray irradiation, the frozen food may be irradiated with a microwave. Thus, the frozen food can be uniformly thawed while maintaining freshness without degradation of the taste and favor thereof.

Abstract: A comestible processing system includes equipment of components for receiving, soaking, draining and tempering food or feed material. Furthermore, infrared material processors are provided for energizing the material with energy in the infrared range. The retention vessel is provided for receiving the heated, energized material for retaining the same in a temperature-elevated condition. A cooler receives the heated material, cools it and flashes off steam therefrom. A processing method includes the steps performed on the material by the above components, and includes additional, optional steps of flaking, grinding and mixing/formulating the material in preparation for packaging same.

Abstract: A raw pizza base is pasteurized and precooked by heating a vitroceramic plate by microwaves to bring the plate to a temperature of from 250.degree. C. to 300.degree. C., removing the plate from the microwaves, placing a raw pizza base on the heated vitroceramic plate for from about 2 minutes to about 3 minutes to pasteurize and precook the pizza base in contact with the vitroceramic plate, and then the pizza base is removed from the vitroceramic plate.

Abstract: A basically commercially fast heat highly efficient griddle has interchangeable griddle plates including magnetically permeable materials having Curie temperatures which may be the same or different to provide different cooking temperatures, the plates being heated by induction coils providing sufficient energy to heat the plates to their effective Curie temperatures in the presence of loads and of a design to maintain a uniform cooking temperature across the griddle plate to within less than an inch of the edges of the plates. The plates may be placed in an enhanced idle condition at cooking temperature by placing a cover over the plates or region of a plate not in use. Increased efficiency is further due to an insulator blanket placed between the griddle plates and coils.

Abstract: An electric wok includes a bowl-shaped pan which has a bottom side with a receiving space and a support frame supporting the bowl-shaped pan. The support frame has an induction coil unit provided with a heat conductive, electric insulating upper plate and an electric insulating lower plate. The induction coil unit is received in the receiving space of the bowl-shaped pan. The induction coil is connected to an external power source. During a cooking operation, a retaining unit engages the bowl-shaped pan to the support frame.

Abstract: An improved structure of a rotisserie, the improvement comprising, a rearrangement of the infra-red heaters to a position not in direct view of the operator, so as to not expose him to its infra-red rays, and the provision of a plurality of circular food holders adjustably positionable on a vertically oriented rotisserie spit on which small items of food can be supported with the aid of food stakes. Small drip dispensors can also be disposed on the circular food holders to supply cooking fluids to food articles hung below them.

Abstract: A cooking apparatus such as a high-frequency heating-cooking apparatus having a pyroelectric vapor sensor for detecting the cooking condition of food comprises an air duct for delivering vapor to the pyroelectric vapor sensor and a cooling construction for providing cool air to mix with the vapor as well as cool air to cool the pyroelectric vapor sensor.

Abstract: Foodstuff packaged in a material transparent to microwaves is conveyed continuously through an environment pressurized to 2.5 bar max so as to prevent the containers or wrappers bursting or being forced out of shape; in four steps, the temperature is raised quickly to a prescribed treatment value with high frequency microwave radiation, stabilized by applying a combination of lower power microwaves and hot air, held steady with hot air only, and then lowered by cooling.

Abstract: Described is a process for producing a cooked edibly browned storage-stable fibrous proteinaceous muscle tissue foodstuff including the steps of:(a) providing a particulate flowable flavoring powder which contains individually discretly encapsulated Maillard reaction reagents with the reduction reagents being at least one encapsulated amino acid and at least one encapsulated sugar;(b) providing an uncooked fibrous proteinaceous muscle tissue foodstuff containing more than 50% water;(c) placing in intimate the contact with at least part of the surface of the foodstuff, a flavor augmenting, imparting or enhancing quantity of the particulate flowable flavoring powder of (a); and(d) exposing the flavoring powder coated foodstuff surface to microwave powder-radiation for a period of time to cause the foodstuff to be ediblewhereby the resulting product is caused to be edible as a foodstuff and the cooked fibrous proteinaceous muscle tissue is edibly browned.

Abstract: A domestic cooking system including at least one cooking utensil defining a food heating surface and including heating apparatus operative to heat the food heating surface by thermal conduction, and a base defining one or more cooking locations arranged for removable engagement with at least one cooking utensil and including apparatus for providing energy to the heating apparatus including an electrical connector disposed at at least one of the cooking locations and configured for mating engagement with at least one of the utensils. There is also provided a domestic cooking system including a base defining at least one cooking location and including electromagnetic induction apparatus including an induction producing element operative to generate electromagnetic flux and at least one high permeability foil disposed so as to direct electromagnetic flux generated by the induction producing element to the cooking location.

Abstract: The invention relates to a package for electrical conduction cooking of a food product contained therein wherein the electrodes include a raised portion of the bottom wall and a planar top electrode and wherein the recessed area between the raised portion of the bottom wall and the sidewall of the package defines a peripheral reservoir to allow the drainage and accumulation of exuded products from the food product being cooked so as to prevent contamination of the bottom electrode.

Abstract: An apparatus for preparing a cooked food product such as a potato chip without the use of oil. The apparatus includes a first infrared heating source to warm the exterior of the sliced potato pieces, a microwave energy source to warm the interior of the potato pieces, and a second infrared heating source to achieve browning of the potato pieces. The crisp, chip-type snack food product thereby produced is low in calories.

Abstract: The present invention is directed to methods and apparatus for preserving fluid foodstuffs, and more particularly is directed to such methods and apparatus for extending the shelf life of perishable fluid foodstuffs such as dairy products, fruit juices and liquid egg products, which are growth media for microorganisms. The present invention is also directed to preserved liquid foodstuffs which have extended shelf life.

Abstract: A treatment of a liquid or slurry which combines the effects of heat, ultrasonification, and pressure to produce an effective bactericide and sporicide. The ultrasonification effect is enhance 10-20 fold by the addition of pressure during the heat and ultrasonification treatment. The pressure results in enhancement of the cavitational effect. The enhance of the cavitational effect results in the heat becoming a more effective bactericide and sporicide at a lower temperature and shorter duration.

Abstract: An improved structure induction heating wok comprising a wok, with a handle and pivoted on one side, from whose lower surface two contact rods extend, a magnetic core wound by a coil, driven by an A.C. power supply, and a bowl shaped yoke with a hollow well containing liquid mercury formed on the upper rim thereon. Wherein, when the pan is in a lowered position, the two contact rods are inserted into the mercury filled hollow well allowing an induced current in the yoke to flow through the contact rods and wok pan to generate heat therein. By pulling up on the handle, the wok pan tilts upwards about the pivot to allow the foodstuff within the wok to be rapidly removed.

Abstract: The electroplasmolyzer for processing plant raw material comprises a cylindrical casing (1) having inlet and outlet holes (2, 3) and electrodes (5) arranged uniformly along a generating line within the cylindrical casing (1). The electroplasmolyzer, according to the invention, also comprises T-shaped electromagnets (6) disposed uniformly on the outer surface along the generating line of the cylindrical casing (1). The number of the electromagnets (6) is a multiple of three. Each electromagnet (6) is arranged above an interelectrode space formed by adjacent electrodes (5) to which its coil (8) is connected. An axis (9) of a yoke (10) of each electromagnet (6) is parallel to a longitudinal axis (4) of the cylindrical casing (1).

Abstract: A vending machine stores a plurality of cups that are filled with primary food products and sealed with covers, and on command, dispenses one cup from the plurality of cups, removes the cover from the one cup, and adds secondary food products to the primary food product in the one cup. The primary food product can be heated. The operation of the vending operation is automatically controlled.

Abstract: A treatment of a liquid or slurry which combines the effects of heat, ultrasonification, and pressure to produce an effective bactericide. The ultrasonification effect is enhance 10-20 fold by the addition of pressure during the heat and ultrasonification treatment. The pressure results in enhancement of the cavitational effect. The enchance of the cavitational effect results in the heat becoming a more effective bactericide at a lower temperature and shorter duration.

Abstract: A bulk material processor includes a tray assembly with a panel subassembly having an upper panel section and a lower panel section. The upper panel section is adapted to receive bulk material and pass it to the lower panel section for discharge. A heater panel is mounted over the tray assembly for radiantly heating the bulk material passing thereunder. A vibrator is coupled to the tray assembly for vibrating the bulk material whereby it advances along the tray assembly. A control system is provided for controlling the operation of the vibrator and for controlling the output of the heater panel. A method of bulk material processing includes cascading the bulk material from an upper panel section to a lower panel section by vibration and subjecting it to infrared radiation.

Abstract: A method and an apparatus which can manufacture dried foods giving the person who eats the dried foods a soft-dried and spongy feeling pleasant to the palate by evaporating the greater part of the moisture in the raw materials to be removed in as short a time as possible after the commencement of the drying process. According to the present invention, this is achieved by a method for manufacturing dried foods wherein raw food materials are radiated with microwaves under reduced pressure conditions while immersed in oil as well as by an apparatus for manufacturing dried foods comprising an oil tank arranged within a pressure reducing chamber having a pressure reducing device; a retainer for containing raw food materials immersed in oil in said oil tank; and a microwave radiating device for radiating said raw food materials with microwave while immersed in the oil.

Abstract: The present invention is drawn to a combination microwave/infrared oven heating a box-like structure in which a plurality of chambers are defined. A microwave heating source is associated with at least one of the chambers for generating microwaves therein, an infrared short-wave radiation source is associated with at least another one of the chambers for generating short-wave infrared radiation therein, and a medium-wave infrared radiation source is associated with at least yet another one of the chambers for generating medium-wave infrared radiation therein. A rotary conveyor is rotatably supported in the oven within the box-like structure and conveys foodstuffs in the oven successively through the chambers. An electronic circuit including a central logic system controls the operation of the rotary conveyor to set the time periods during the foodstuffs conveyed in the oven remain in respective ones of the chambers.

Abstract: In order to stabilize pre-packaged food products and simultanously sanitize the packages, the packages are treated with microwaves in a first processing zone in an atmosphere where hot air is maintained at a superatmospheric pressure. The hot hair is thermostat-regulated at a temperature slightly above that which has been set for stabilizing the food products. The packages are then transferred to a second processing zone maintained at the temperature and pressure of the first zone but free of microwaves. The packages are then transferred to a cooling zone for cooling at a predetermined cooling temperature at superatmospheric pressure. The hot and cold air in the heating and cooling zones are kept in constant motion.

Abstract: Application of substantial pressure to ends of a frankfurter, concurrent with passing of electrical current, through the application of a cooking tray whose structure accepts multiple frankfurters and allows the pressure to be applied by the use of a carriage system with multiple plungers whose points of contacts serve as electrodes; use of aluminum foil patches between the extremities of the frankfurter and electrode plunger cups is made to maintain conductivity with said aluminum patches being applied by use of a paper tape sprocket system which is microprocessor controlled or in the alternative by manual operator insertion in a modified cooking tray which eliminates the need of the paper tape sprocket system. Application of pressure to extremities of the frankfurter is well in excess of that required for mere electrical contact, but is part of the cooking process for producing a processed frankfurter in less than 40 seconds with high reliability by passing an electric current without burning or arcing.

Abstract: A container body is sealed by means of a lid made of a flexible sheet having an insulative property and an antenna made of an electrically conductive material which is laminated upon the lid. According to this construction, when the container body is exposed to microwaves within a microwave oven, microwave energy is concentrated at a position near the front end of the antenna and the microwave energy is converted into heat energy, whereby the lid is opened by means of the thus converted heat. The lid can thus be precisely partially melted so as to form an opening of a predeterminedly suitable size.

Abstract: An extruder operating to continuously mix, at least partially bake and extrude a preselected formulation of ingredients to provide an at least partially baked output product which, upon final baking, exhibits a cookie-like crumb structure with structural integrity. The extruder includes an added water inlet port downstream from a feed port means. A screw-type element is rotatably arranged in the extruder to vigorously mix and convey at least certain ingredients of the preselected formulation, including flour and oil, input through the feed port means, wherein the total water content, by weight, of the ingredients is less than a preselected amount. A temperature control means operates to heat treat the ingredients upstream from the added water inlet port during the vigorous mixing and conveyance by the screw-type element.

Abstract: A high-frequency dielectric oven uses a plurality of oscillating circuits, which are caused to operate in a predetermined phase relationship, to produce a higher voltage distribution within a load capacitor, thus permitting an increase in the space between the electrode plates of the load capacitor to enable use of the oven for heating commercial quantitites of foodstuff. The generated electric field has a distribution which minimizes the number of nodes of a standing wave, thus reducing the occurrences of cold spots in the heating cavity. A plurality of tray levels are provided, each level having a separate pair of electrodes generating the electric field therefor. The electrodes may be shaped to provide direct support for the trays. Power transferred to the foodstuff is controlled by a variable air gap capacitor and the power tube operates at a substantially constant power level, irrespective of the power being transferred to the foodstuff.

Abstract: An apparatus is provided for uniformly and rapidly heating, pasteurizing and/or sterilizing food products which comprises a conveyor on which the food products are conveyed and a source of radio-frequency radiation which is directed at the food products. The source is connected to shaped electrodes, the shaping of the electrodes and their spacing from the food product being selected in dependence upon the configuration and irradiation required of the product being treated. The food product may be a pre-cooked meal comprising a plurality of constituents and the electrode is then shaped to take into account the geometry of the different constituents and in combination with the spacing of the electrode from the product, takes the heating requirements of the individual components into account.

Abstract: Microwave absorbing composite comprising at least two zones of material capable of absorbing microwave energy, each set of said two zones being separated by one zone of material transparent to or transmissive of microwave energy. The microwave energy absorbing zones are selected such that the composite is incapable of arcing in a microwave oven whereof the maximum power output does not exceed 2000 watts at a frequency of 2.45 GHz.The composite of this invention can be used for such purposes as crisping, browning, or otherwise heating food products, as a material for packaging, or as a package venting material.

Abstract: A heating apparatus for heating an electrically conductive flowable medium includes a pipe having a conductivity no greater than that of the medium and a pair of electrodes projecting in a cantilever fashion into the pipe at spaced locations therealong and each having a noble metal plated surface exposed to the flowable medium. Each electrode is sealed to the wall of the pipe with a flat-faced aspetic seal formed between a flat end face of the elctrode and a cooperating flat face on the pipe wall. The electrodes may be hollow, fluid cooled and have a rounded free end made of an electrically non-conducting material on which is mounted a temperature or pressure sensor. The exposed electrode surface may be partially coated with an electrically insulative material to confine heating current flow to a particular surface portion of the electrode.

Abstract: An extruder and continuous mixing apparatus operating to continuously mix, at least partially bake and extrude a preselected formulation of ingredients to provide an at least partially baked output product which, upon final baking, exhibits a cookie-like crumb structure with structural integrity. The extruder includes at least one screw-type element which is rotatably arranged in the extruder to vigorously mix and convey at least certain ingredients of the preselected formulation, including flour and oil, input through a feed port means at the upstream end of the extruder, wherein the total water content, by weight, of the ingredients is less than a preselected amount. A temperature control means operates to heat treat the ingredients during the vigorous mixing and conveyance by the screw-type element. The vigorous mixing and heat treatment is applied to the ingredients for substantially the entire length of the extruder.

Abstract: A dielectric method of drying a hot plastic food extrudate comprises extruding the hot plastic food material from a food extruder, passing the extruded hot plastic food material while the material is still plastic to a dielectric heating apparatus which is in close proximity to the food extruder, and subjecting the hot plastic food material to dielectric heating.

Abstract: An extruder operating to continuously mix, at least partially bake and extrude a preselected formulation of ingredients to provide an at least partially baked output product which, upon final baking, exhibits a cookie-like crumb structure with structural integrity. The extruder includes an added water inlet port downstream from a feed port means. A screw-type element is rotatably arranged in the extruder to vigorously mix and convey at least certain ingredients of the preselected formulation, including flour and oil, input through the feed port means, wherein the total water content, by weight, of the ingredients is less than a preselected amount. A temperature control means operates to heat treat the ingredients upstream from the added water inlet port during the vigorous mixing and conveyance by the screw-type element.

Abstract: A method and apparatus for even and rapid heating, pasteurization or sterilization of products contained in a package, such as, for example, pharmaceutical products or food, which are conveyed through a microwave treatment chamber on a continuous conveyor belt. In order to heat components of the products having different heat absorption for the purpose of reaching the pasteurization temperature rapidly and evenly, the temperature of the components is recorded by a temperature sensor, and on the basis of this the computer calculates the respective .DELTA.T, taking into account given product parameters and the desired temperature to be reached. When the product passes under the following input aperture, a given microwave energy level is coupled into each specific component, as a result of which an even temperature of all products in the package is achieved very rapidly without overheating of the product.

Abstract: Infrared (IR) strip heaters are juxtaposed with convection heaters for simultaneous, independently controlled, combined radiant/convective heating in a conveyor oven. Apertured plates with portions transmissive to IR radiation are interposed between a lower combined heating unit and the cooking path. The IR heaters are preferably gas burners with porous, ceramic or metallic elements, the burners on opposite sides of the cooking path being independently controllable to vary the heat transfer rate to opposite food surfaces. Symmetrical placement of the IR heaters in opposed pairs facilitates use of the conveyor oven as a half oven. An auxiliary burner exhausts directly into the convection air and is cycled on and off to maintain a set temperature during normal operation.

Abstract: An extruder and continuous mixing appartatus operating to continuously mix, at least partially bake and extrude a preselected formulation of ingredients to provide an at least partially baked output product which, upon final baking, exhibits a cookie-like crumb structure with structural integrity. The extruder includes at least one screw-type element which is rotatably arranged in the extruder to vigorously mix and convey at least certain ingredients of the preselected formulation, including flour and oil, input through a feed port means at the upstream end of the extruder, wherein the total water content, by weight, of the ingredients is less than a preselected amount. A temperature control means operates to heat treat the ingredients during the vigorous mixing and conveyance by the screw-type element. The vigorous mixing and heat treatment is applied to the ingredients for substantially the entire length of the extruder.

Abstract: Described is apparatus useful in enabling the making of a cooked baked goods foodstuff and in enabling a process to be carried out whereby a Maillard reactant-coated uncooked foodstuff is exposed to microwave radiation for a time sufficient to provide a browned baked goods foodstuff which is cooked in a relatively short period of time. The apparatus comprises:(i) first mixing device for mixing a fluid carrier and Maillard or Amadori reactants;(ii) second mixing device separate from the first mixing device for mixing dough;(iii) shaping device downstream from the second mixing device for shaping the mixed dough;(iv) coating device for coating the composition of (i) onto the shaped dough;(v) microwave cooking device downstream from the coating device to cook the coated shaped dough; and(vi) device for controlling the microwave cooking device to determine the cooking time and to stop the microwave cooking at the expiration of the cooking time defined according to specific mathematical equations.

Abstract: A system for shaping a food product which is initially in the liquid state, such as fresh liquid egg white or yolk, while it is hardening, in which the liquid product is fed to a continuously unwinding band of flexible material, such as Teflon-coated paper which is deformed while in motion from a flat state to the shape of a continuous container and in which the product is treated as by heating until it is hard. After the product is hard the band is restored to its flat state and is drawn in a direction opposite to its original direction while the shaped and hardened product is carried away. Specifically, the means for deforming the band comprises a pair of press rollers having male and female molding parts for marking longitudinal folding lines on the band and flanges for raising the edges of the bands along the longitudinal folding lines. Preferably, the product is heated in a microwave cavity and, during heating, a second band is applied on top of the shaped band to form a steam-tight cover.

Abstract: An extruder and continuous mixing apparatus operating to continuously mix, at least partially bake and extrude a preselected formulation of ingredients to provide an at least partially baked output product which, upon final baking, exhibits a cookie-like crumb structure with structural integrity. The extruder includes at least one screw-type element which is rotatably arranged in the extruder to vigorously mix and convey at least certain ingredients of the preselected formulation, including flour and oil, input through a feed port means at the upstream end of the extruder, wherein the total water content, by weight, of the ingredients is less than a preselected amount. A temperature control means operates to heat treat the ingredients during the vigorous mixing and conveyance by the screw-type element. The vigorous mixing and heat treatment is applied to the ingredients for substantially the entire length of the extruder.

Abstract: A method for heat curing a raw meat medium is disclosed wherein the meat medium is conveyed through a pipe while being subjected to electromagnetic waves having a frequency of less than 300 MHz. A continuous heating of the meat medium is hereby effected so that the heating thereof is finished when it leaves the pipe and immediately thereafter while its temperature is still at least 70.degree. C., can be cut into slices or pieces and packed.

Abstract: An apparatus is provided for the uniform and rapid heating of foodstuffs, usually for pasteurization and sterilization purposes, by means of microwave energy. The cross-sectional shape of the outlet of the wave guides through which the microwave energy is supplied is selected so as to be geometrically similar to that of the product to be treated. A spacing is maintained between the outlet aperture and the surface of the product, which spacing is not greater than the wavelength of the microwave energy be used. These features provide rapid and appropriate processing of a food product while, at the same time, preventing the harmful overheating of the edge regions of the product.

Abstract: An appliance for the continuous treatment of foodstuffs or the like by means of microwaves in a treatment chamber, which allows individual adaptation to different product-pack heights and geometrical product forms, while at the same time ensuring the best possible utilization of the microwave energy supplied. The arrangement of an adjusting device outside the treatment chamber for axially adjusting the microwave feed ducts along their longitudinal axes and for rotating of the feed ducts about their longitudinal axes ensure that the product to be treated is subjected to the microwave energy as efficiently as possible, without the treatment process having to be interrupted by stopping it and opening the treatment chamber.

Abstract: Microwave apparatus for heating discrete packages (12) of product. The microwave apparatus has a support surface (14) for a packaged product within a waveguide (2), a microwave field generator, and field deflecting and concentrating guide (4,6) to produce a raised value of energy in the field in the interior region of the package so as to uniformly heat the package (12).

Abstract: A sterilizing method for treatment of fresh fruits and an apparatus used for the method that allow a significant reduction of steam consuption and of fruit sterilization cost is disclosed.The present invention is characterized by that extermination of vermin eggs and sterilization and disinfection of fresh fruits is conducted without deteriorating the freshness of the fruits to be treated by irradiating far infrared rays on the fruits to preheat the cores of the fruits to a predetermined temperature and then by maintaining the fruit cores at a predetermined temperature for a predetermined period of time in saturated steam.

Abstract: A microwave oven includes a microwave source and a defrost detector arranged in the oven cavity in the proximity of a frozen product to be processed, the absorption of microwave energy being distributed between the detector and the product and causing their temperature to rise, the temperature variation of the detector being measured by a measuring element producing a corresponding electrical signal. The oven also includes a computing control device which determines completion of defrosting of the product by computing the values at successive instants of the second derivative of such signal as a function of time. The computing control device controls the oven at the end of the defrosting cycle, which is when the value of such second derivative falls below a predetermined value.