PRESERVATION OF FRUITS AND VEGETABLES 5 



Another grader sorts out easily rolling materials according to diame- 

 ter. As a mechanically driven cable rolls the materials along an open- 

 ing that increases in width, the product falls through and is collected 

 according to size. 



A grader based on the same principle passes the product down a 

 chute the floor of which consists of rollers placed at increasingly greater 

 distances apart. As the product rolls along the chute, it is separated 

 in progression according to size. 



Peeling 



Manufacturers show a growing tendency to remove the skin from 

 all fruits and vegetables before drying. Because of custom or the 

 type of skin, some kinds, notably prunes and apricots, however, are 

 rarely peeled. 



Peeling may be done by hand or by specially designed machines. 

 Many types of knives, with straight, curved or guarded blades, and 

 hand-operated cutting machines are obtainable for peeling, trimming, 

 coring, and otherwise preparing the material to be dried. Machines 

 for peeling and coring both apples and pears in -one operation are 

 available. 



Friction or rotary mechanical peelers are particularly well suited 

 for handling roots and tubers. All peelers of this type depend upon 

 the rasping effect of rough surfaces of cement, corundum, etc., form- 

 ing some part of the lining of the peeler, when the product is rotated 

 rapidly within the cylinder by a moving bottom. The material is 

 introduced at the top and discharged by a side door. These ma- 

 chines are usually equipped with water sprays, which wash off the 

 dirt and the particles of skin removed by the peeler. Other types 

 make use of an open flame which chars the skin so that it can be brushed 

 or washed off. 



Several types of lye peelers are available. All depend upon immers- 

 ing in or spraying with hot (190°-200° F.) lye solution. The length of 

 treatment must be determined for each batch of fruit. It should be 

 long enough to permit the ready removal of skin by water sprays or 

 by rubbing but must not injure the flesh of the product being peeled. 



Trimming 



Following the peeling, the fruit or vegetable must be inspected and 

 all remaining skin removed with trimming knives, especially adapted 

 to different products. 



Checking 



Lye is used to check the skins of prunes and grapes, in order to 

 facilitate drying. The fruit is in contact with the hot lye solution long- 

 enough to break the skin by many minute fissures or checks, but not 

 long enough to loosen it. The concentration and temperature of the 

 lye bath are similar to those for lye peeling. After the lye treatment 

 the fruit is carefully washed to remove all traces of the lye bath 

 before further processing. 



Subdividing 



Fruits are sliced, cubed, shredded, or left whole, Vegetables are 

 sliced, cubed, shredded, or chipped. The cutting is clone by hand or 



