Abstract: An apparatus assembly for heating a product has a tunnel and microwave generators positoned for generating a microwave field zone within the tunnel. A conveyor belt extends within the tunnel for passing a product through the tunnel. A plate formed of a material impermeable to microwaves is positioned in the tunnel so that an entire width of the belt passes over the plate in the microwave field zone so that microwave energy is reflected away from the belt. In addition, heating elements for generating an infrared energy zone and a further conveyor belt may be positioned so that a product passed through the tunnel then is passed by the further conveyor belt through the infrared energy zone.

Abstract: A custard product is prepared by passing a container containing a liquid custard mix through a microwave field and exposing the liquid mix to microwave field energy, but so that microwave field energy at a position below a position of a base of the mix in the container is reflected away from the mix base, for a time to heat the custard mix to initiate setting the mix and so that upon leaving the field, a contained custard product has a temperature of from 90.degree. C. to 95.degree. C. The custard product then may be exposed to infrared energy to firm and brown the product.

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: 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: The degree of roasting of materials roasted by application of microwaves is regulated by a system free from any energy source which receives material from a microwave roaster and retains it for a time for completing roasting and varying and regulating the final degree of roasting of the material by regulating the feed of the roasted material from the system to a quenching zone. The microwave roaster includes a horizontal rotatable tube which has baffles for transporting the material to be roasted through the tube such that it reaches a roasting temperature at the outlet of the tube for receipt by the system for achieving the desired degree of final roasting.

Abstract: A process and an apparatus for the homogeneous heat treatment of a liquid which induces a helical swirling motion to the liquid to obtain a substantially homogeneous final thermal state and constant final temperature of the liquid. The liquid is moved through a vertical cylindrical tube which contains a central column and at least one perforated plate and is exposed to a microwave energy field as it moves through the tube.

Abstract: A process and an apparatus for the homogeneous heat treatment of a liquid which induces a helical swirling motion to the liquid to obtain a substantially homogeneous final thermal state and constant final temperature of the liquid. The liquid is moved through a vertical cylindrical tube which contains a central column and at least one perforated plate and is exposed to a microwave energy field as it moves through the tube.

Abstract: A process and an apparatus for freeze-drying by means of microwaves, in which the product to be dried is placed on a support composed of a material which is transparent to microwave energy, covered with a layer of material which conducts electricity.