Abstract: A process for making a shelf-stable food, not requiring preservatives or refrigeration and in a form that is convenient for use as a snack food. A block of tofu or wheat gluten is first frozen so as to cause the formation of ice crystals that form cavities within the block. The frozen block is then thawed, cut into smaller pieces and drained of excess water. The thawed pieces are dried in a microwave-vacuum dehydrator to produce a crunchy food product.

Abstract: A method and apparatus for pasteurizing and drying cannabis plant materials using a microwave-vacuum chamber. The pasteurizing and drying are carried out with no use of ionizing radiation and with rapid drying. Pasteurization is done at a temperature and for a time period that are sufficient to reduce microorganisms to an acceptably low level, while not significantly reducing the psychoactive compounds in the material. In the process, the pressure inside a vacuum chamber is reduced to a first pressure less than atmospheric. The material is maintained in the vacuum chamber at the first pressure at a pasteurizing temperature while irradiating the material with microwave radiation. The pressure is then reduced to a second pressure lower than the first pressure and the material is maintained in the vacuum chamber at the second pressure for a time period at a dehydrating temperature lower than the pasteurizing temperature while irradiating the material with microwave radiation.

Abstract: An apparatus and method for dehydrating biological materials, such as vaccines and microorganism cultures, in which the materials are dehydrated in an evacuated container which is in a microwave waveguide that is open to the atmosphere. The apparatus comprises means for freezing the container of biological material, a microwave generator, a waveguide, means for introducing the container into the waveguide, means for applying a vacuum to the container and means for removing the dehydrated material from the waveguide. In the method of the invention, the container of biological material is put in a microwave waveguide open to the atmosphere, a vacuum is applied to the container, the material is frozen and is radiated to dehydrate it. The dehydrated material is then removed from the waveguide.

Abstract: A method and apparatus for pasteurizing and drying cannabis plant materials using a microwave-vacuum chamber. The pasteurizing and drying are carried out with no use of ionizing radiation and with rapid drying. Pasteurization is done at a temperature and for a time period that are sufficient to reduce microorganisms to an acceptably low level, while not significantly reducing the psychoactive compounds in the material. In the process, the pressure inside a vacuum chamber is reduced to a first pressure less than atmospheric. The material is maintained in the vacuum chamber at the first pressure at a pasteurizing temperature while irradiating the material with microwave radiation. The pressure is then reduced to a second pressure lower than the first pressure and the material is maintained in the vacuum chamber at the second pressure for a time period at a dehydrating temperature lower than the pasteurizing temperature while irradiating the material with microwave radiation.

Abstract: A method of drying an organic material by microwave-vacuum drying below but close to the triple point of water has been determined to allow more conversion of microwaves to heat than would occur when microwave freeze-drying at lower pressures. The method comprises introducing the organic material into a microwave-vacuum dehydrator, exposing the organic material to microwave radiation in the dehydrator to dry the organic material by sublimation, and maintaining pressure in the dehydrator in the range of 0.5 Torr to 4.5 Torr. The method provides the benefits of reduced drying time, energy requirements and product temperatures, relative to dehydration done at lower vacuum pressures.

Abstract: An apparatus and method for microwave vacuum-drying of organic materials such as food products. The dehydration apparatus (10) has a vacuum chamber (12) with a loading module (14) at one end and a discharge module (22) at the other. The vacuum chamber has access doors (80) spaced between the input end (16) and the discharge end (24) which provide operator and maintenance access. Microwave generators (86) are mounted on each access door and arranged to radiate through a microwave chamber and microwave-transparent window on the access door into the vacuum chamber. The waveguides on a respective access door are oriented to minimize microwave interference between the magnetrons on that door. A conveyor (60) in the vacuum chamber moves the organic material (96) on trays (18) through the vacuum chamber.

Abstract: A method of making a puffed, dehydrated food product comprises mixing a high amylopectin starch and selected food ingredients to form a dough; forming the dough into pieces; and exposing the dough pieces to microwave radiation at a pressure less than atmospheric to puff and dry the dough pieces, producing the puffed, dehydrated food product. The ingredients may include tomato paste, yogurt, fruit or fruit juice concentrate, fruit puree, vegetable puree, vegetable puree concentrate, coffee, and concentrated soup. The dough may be formed in the absence of starch hydrolysates. The method produces dehydrated food products which incorporate a variety of food ingredients in a matrix that has a puffed, crispy structure.

Abstract: A method of making a porous, crunchy, dehydrated, vegetable, meat or seafood snack product. A piece of vegetable, such as potato, sweet potato, carrot, beet or parsnip, or a piece of meat or seafood, is frozen, forming ice crystals within the piece of food. The frozen piece is exposed to microwave radiation in a microwave-vacuum dehydrator at a vacuum pressure at which the boiling point of water is above 0° C., causing the frozen piece to thaw and water to evaporate from the thawed piece. The evaporation leaves pores that were formed by the ice crystals within the piece of food, resulting in a porous, crunchy, dehydrated snack product.

Abstract: An apparatus and method for microwave vacuum-drying of organic materials, such as food products. The apparatus has a microwave vacuum chamber 20, a loading module 36 to load containers 38 of the organic material into the vacuum chamber, a rotatable cylindrical cage 64 in the vacuum chamber for rotating the containers, a piston 114 for moving the rotating containers through the vacuum chamber, and means for unloading the containers of dehydrated material from the vacuum chamber. The apparatus may include an equilibration chamber 150 for cooling the dehydrated material under reduced pressure, and a transfer module 42 to transfer the containers from the vacuum chamber to the equilibration chamber. The apparatus has a microwave transparent window 54 for transmission of radiation into the vacuum chamber, and a gas jet 58, 60, 62 for blowing a stream of gas, such as air or nitrogen, into the vacuum chamber adjacent to the window.

Abstract: An apparatus 20 for microwave vacuum-drying organic materials such as foods and bioactives has a plurality of microwave generators 50 actuated so as to cause interference between their respective microwave streams and evenly distribute the microwave energy across the vacuum chamber 34. The microwave-transparent window 36 in the chamber is arranged so the organic material to be dried is moved across it on a conveyor belt 60 and the microwave energy passing into the chamber 34 immediately encounters the organic materials, thus attenuating the energy and reducing arcing.

Abstract: An apparatus 20 for microwave vacuum-drying organic materials such as foods and bioactives has a plurality of microwave generators 50 actuated so as to cause interference between their respective microwave streams and evenly distribute the microwave energy across the vacuum chamber 34. The microwave-transparent window 36 in the chamber is arranged so the organic material to be dried is moved across it on a conveyor belt 60 and the microwave energy passing into the chamber 34 immediately encounters the organic materials, thus attenuating the energy and reducing arcing.

Abstract: An apparatus and method for dehydrating biological materials, such as vaccines and microorganism cultures, in which the materials are dehydrated in an evacuated container which is in a microwave waveguide that is open to the atmosphere. The apparatus comprises means for freezing the container of biological material, a microwave generator, a waveguide, means for introducing the container into the waveguide, means for applying a vacuum to the container and means for removing the dehydrated material from the waveguide. In the method of the invention, the container of biological material is put in a microwave waveguide open to the atmosphere, a vacuum is applied to the container, the material is frozen and is radiated to dehydrate it. The dehydrated material is then removed from the waveguide.

Abstract: A process for making a shelf-stable food, not requiring preservatives or refrigeration and in a form that is convenient for use as a snack food. A block of tofu or wheat gluten is first frozen so as to cause the formation of ice crystals that form cavities within the block. The frozen block is then thawed, cut into smaller pieces and drained of excess water. The thawed pieces are dried in a microwave-vacuum dehydrator to produce a crunchy food product.

Abstract: An apparatus 20 for microwave vacuum-drying organic materials such as foods and bioactives has a plurality of microwave generators 50 actuated so as to cause interference between their respective microwave streams and evenly distribute the microwave energy across the vacuum chamber 34. The microwave-transparent window 36 in the chamber is arranged so the organic material to be dried is moved across it on a conveyor belt 60 and the microwave energy passing into the chamber 34 immediately encounters the organic materials, thus attenuating the energy and reducing arcing.

Abstract: An apparatus 20 for microwave vacuum-drying organic materials such as foods and bioactives has a plurality of microwave generators 50 actuated so as to cause interference between their respective microwave streams and evenly distribute the microwave energy across the vacuum chamber 34. The microwave-transparent window 36 in the chamber is arranged so the organic material to be dried is moved across it on a conveyor belt 60 and the microwave energy passing into the chamber 34 immediately encounters the organic materials, thus attenuating the energy and reducing arcing.

Abstract: An apparatus and method for dehydrating biological materials, such as vaccines and microorganism cultures, in which the materials are dehydrated in an evacuated container which is in a microwave waveguide that is open to the atmosphere. The apparatus comprises means for freezing the container of biological material, a microwave generator, a waveguide, means for introducing the container into the waveguide, means for applying a vacuum to the container and means for removing the dehydrated material from the waveguide. In the method of the invention, the container of biological material is put in a microwave waveguide open to the atmosphere, a vacuum is applied to the container, the material is frozen and is radiated to dehydrate it. The dehydrated material is then removed from the waveguide.

Abstract: An apparatus 20 for microwave vacuum-drying organic materials such as foods and bioactives has a plurality of microwave generators 50 actuated so as to cause interference between their respective microwave streams and evenly distribute the microwave energy across the vacuum chamber 34. The microwave-transparent window 36 in the chamber is arranged so the organic material to be dried is moved across it on a conveyor belt 60 and the microwave energy passing into the chamber 34 immediately encounters the organic materials, thus attenuating the energy and reducing arcing.

Abstract: An apparatus and method for microwave vacuum-drying of organic materials such as food products. The dehydration apparatus (10) has a vacuum chamber (12) with a loading module (14) at one end and a discharge module (22) at the other. The vacuum chamber has access doors (80) spaced between the input end (16) and the discharge end (24) which provide operator and maintenance access. Microwave generators (86) are mounted on each access door and arranged to radiate through a microwave chamber and microwave-transparent window on the access door into the vacuum chamber. The waveguides on a respective access door are oriented to minimize microwave interference between the magnetrons on that door. A conveyor (60) in the vacuum chamber moves the organic material (96) on trays (18) through the vacuum chamber.

Abstract: An apparatus 20 for microwave vacuum-drying organic materials such as foods and bioactives has a plurality of microwave generators 50 actuated so as to cause interference between their respective microwave streams and evenly distribute the microwave energy across the vacuum chamber 34. The microwave-transparent window 36 in the chamber is arranged so the organic material to be dried is moved across it on a conveyor belt 60 and the microwave energy passing into the chamber 34 immediately encounters the organic materials, thus attenuating the energy and reducing arcing.

Abstract: An apparatus and method for microwave vacuum-drying of temperature-sensitive biological materials on a continuous flow-through basis, in which the materials are frozen, ground to frozen particles, dehydrated to a powder, and the powder collected. The apparatus has a microwave generator and waveguide, a freezing chamber with a grinder, a rotatable dehydration chamber in or adjacent to the waveguide, and a powder collector to receive the powdered biological material. The apparatus operates under reduced pressure provided by a vacuum system coupled to the powder collector.