Method and apparatus for drying or heat-treating products

Abstract

The invention relates to a method and an apparatus for drying or heat-treating substances or products at a pressure other than atmospheric pressure. The invention relates furthermore to banana chips dried by means of this method and banana powder produced therefrom. For drying or heat-treating, the products to be treated are loaded in transport receptacles which are subsequently charged via charging lock chambers into a treatment chamber and discharged therefrom via discharging lock chambers. For drying or heat treating, at least one microwave source is provided in the treatment chamber. After heat-treating or drying, a resting period may be scheduled. More particularly for this purpose, a vertically-oriented conveying system is provided in the treatment chamber when a longish resting period is involved. The transport receptacle is configured dished and my comprise nets on which the products are applied. The method is employed preferably for drying or heat-treating basic food material, e.g. for food products or medicinal drugs.

What is claimed is:  
     
         1 . Dried fruit, dried vegetable or that like food, namely dried banana, wherein said food, 
 in a first treatment step, is shredded or chopped into pieces and is predried;    in a second treatment step, is subjected to a heat treatment in a vacuum by means of microwave treatment so that a cellular break-up and puffing up of said food occurs for obtaining well hydratable food having an instant character;    in a third treatment step, said food is finally dried and packed.    
     
     
         2 . Dried food as set forth in  claim 1 , wherein said heat treatment in said vacuum is performed at an atmospheric pressure, preferably in the range 20-100 mbar.  
     
     
         3 . Dried food as set forth in  claim 1 , wherein said food is milled into food-powder.  
     
     
         4 . Dried food as set forth in  claim 1 , wherein said food is banana.  
     
     
         5 . Dried fruit, dried vegetable or that like food, namely dried banana, wherein said food is prepared comprising the steps of: 
 shredding or chopping the food in a first treatment step into pieces and predrying the food;    heat treating in a second treatment step in a vacuum by means of microwave treatment so that a cellular break-up and puffing up of said food occurs for obtaining well hydratable food having an instant character;    drying and packing said food in a third treatment step.    
     
     
         6 . Dried food as set forth in  claim 4 , wherein said food is milled into food-powder.  
     
     
         7 . Dried food as set forth in  claim 4 , wherein said food is banana.