초록

A method and apparatus for vacuum dehydrating fruit to a moisture content below about 15% but preferably below about 5%, using combined infrared energy and microwave energy simultaneously.

대표청구항 ▼

A vacuum dryer for removing moisture from a food product comprising: chamber means defining an elongated cavity having an inlet end and an outlet end; means for evacuating said cavity to a vacuum; inlet means communicating with said inlet end for presenting said food product into said cavity; outlet

A vacuum dryer for removing moisture from a food product comprising: chamber means defining an elongated cavity having an inlet end and an outlet end; means for evacuating said cavity to a vacuum; inlet means communicating with said inlet end for presenting said food product into said cavity; outlet means associated with said outlet end for removing said food product from said cavity; conveyor means in said cavity for moving said food product from said inlet end to said outlet end through first and second heating zones on a preselected path; first infrared energy means and first microwave energy means operative simultaneously in said first heating zone for simultaneously heating the exterior and interior of said food product moving on said conveyor means along said path and through said first heating zone; second infrared energy means and second microwave energy means operatively associated with said cavity for simultaneously heating the interior and exterior of said food product moving on the conveyor means along said path and through said second heating zone; first control means for controlling the energy of said first infrared energy means to provide a predetermined surface temperature for said food product moving through said first zone; second control means for controlling the energy level of said first microwave energy means to provide predetermined internal heating of said food product in said first zone, said first control means and said second control means being effective to establish a moisture gradient toward the outer surface of said food product in said first zone and a surface temperature at said vacuum effective for evaporating substantially all of the moisture exiting from said food product; and, cooling means operatively associated with said outlet means for receiving said food product from said conveyor means and effective to cool said food product and discharge said food product at atmospheric pressure exterior of said chamber means.