VEGETABLE AND FRUIT DEHYDRATION 213 



Fresh apples can be stored for several months at 35° to 38° F. 

 The length of storage period varies with the variety. Spray residue 

 must be removed from apples before they are used; removal can be 

 accomplished by means of a hydrochloric acid wash. Further prepa- 

 ration includes peeling, coring, trimming, slicing, and sulfuring. 



The best, although not the standard, method of grading dried apples 

 is based on quality of sauce, pie, or other product. By this method, 

 varieties of inherently good cooking quality rank high, and such varie- 

 ties are best for dehydration because all dried apples are cooked. In 

 commercial practice, the whitest dried apples are rated highest regard- 

 less of variety. Whiteness, however, is to a considerable extent con- 

 trolled by sulfuring. Late-maturing, firm-fleshed varieties are gen- 

 erally suitable for drying. Apples are sulfitecl by dipping for 15 to 

 20 seconds in a 0.25 percent solution of sodium bisulfite after slicing or 

 by exposure to the fumes of burning sulfur for about 20 minutes after 

 peeling but before slicing. 



Apples are commonly dried in kilns, or evaporators. The fresh 

 slices are spread about 18 inches deep on a slatted floor ; hot air passes 

 through the fruit, which is turned once or twice with a shovel, and the 

 finished fruit (after about 20 hours of drying) is shoveled into bins. 

 Apples can also be dried by mechanical, forced-air dehydration 

 (table 28). This method is used extensively in Canada, where the 

 center-exhaust system is advocated {H). Apple crisps, or nuggets, 

 are produced by coarsely grinding evaporated apples and drying the 

 small pieces to 3 percent moisture content or lower (Government pur- 

 chase specification) by the vacuum process. This product has much 

 better keeping quality, especially at higher temperatures, than ordi- 

 nary dried apples. 



apricots 



Commercial production of apricots is restricted to the Pacific coast, 

 with 90 percent in California. During the years 1936-40 about 65 per- 

 cent of the California crop was dried, 25 percent was canned, and 10 

 percent sold in the fresh state. Increasing amounts are being pre- 

 served by freezing. The production in the other States is sold for 

 the most part on the fresh-fruit market. Almost half of the dried 

 apricot pack is expbrted. The Blenheim and Koyal varieties, which 

 are indistinguishable, are preferred for drying because they bear well 

 and the dried product is excellent in quality. Other varieties com- 

 monly dried are Tilton and Moorpark. 



Fresh apricots cannot be stored more than 1 or 2 weeks, and for best 

 dessert qualities they must be harvested when fully ripe, They are 

 never peeled before being dried. Preparation includes washing, halv- 

 ing, and pitting. Trays are loaded with a single layer of halves, laid 

 with the cups up. The fruit is then sulfured and dried in the sun. 

 If it is to be dehydrated, it should be blanched about 3 minutes prior 

 to sulfuring. Apricot powder is made by grinding dried apricots and 

 drying the ground material under vacuum to a low moisture content 

 (2y 2 percent for Government purchase). 



BERRIES (INCLUDING CRANBERRIES) 



Strawberries are produced commercially in many States, with large 

 commercial production in Arkansas, Louisiana, and Oregon. Most 



