VEGETABLE AND FRUIT DEHYDRATION 



135 



FiouEE 65.-Hydranlic press used in compression ^J^^j^!^%^ 

 dehydrated foods at the Western Regional Research Laboratoiy, Albany, Cain. 



by the plunger past the sides of the mold. Friction resulting from 

 unpolished, inadequately lubricated steel surfaces diverts part of 

 the pressure from the foodstuff to the sides of the mold; thus the 

 effective pressure is decreased at the bottom of the mold, and poor 

 cohesion and a laminated, leafy brick may result. 

 " Sometimes very fine, dried materials or even powder are com- 

 pressed. Examples are soup mixtures and dehydrated tomato-jmce 

 cocktail. Most dry powders flow readily and uniformly and such 

 conditions are essential in the automatic feeding of presses. JJe- 

 hvdrated soup powders have been processed satisfactorily on indus- 

 trial tablet-compressing machines. Dried tomato juice of 4 percent 

 moisture content has been readily compressed hydrauhcally by 1,500 



