PRESERVATION OF FRUITS AND VEGETABLES 37 



SWEETPOTATOES 



Sweetpotatoes can be dehydrated, and will produce an acceptable 

 food. They are peeled by abrasive machines, sliced in %" pieces, 

 and steam blanched for 10 to 20 minutes. Temperatures as high as 

 160° F. can be used at the start, 140° at finish. 



TOMATOES 



Although dehydrated tomatoes have great possibilities for use in 

 ketchups, purees, and soups, as well as in the stewed form, their 

 commercial production has not been extensive. Only firm, fully 

 colored tomatoes should be used. The Stone is a satisfactory variety. 



Tomatoes to be dried first receive a thorough washing with sprays 

 of cold water. If they are to be used in the stewed form, they should 

 be dipped in boiling water or subjected to jets of live steam for a few 

 seconds to loosen the skin, chilled in cold water, and peeled by hand, 

 when the stem cores are removed. To slice the trimmed tomatoes for 

 dehydration without excessively bruising and breaking them requires 

 the use of a slicing machine with sharp and rapidly rotating knives. 

 The tomatoes are then carefully trayed, one slice deep, and they may 

 or may not be lightly steamed. 



To insure satisfactory keeping qualities, the lack of which has been 

 the principal reason for not producing them commercially, tomatoes 

 must be dried to about 5-percent moisture content, when they will 

 snap from the trays in whole slices if the trays are lightly tapped on 

 the bottom. As the dried product is very hygroscopic, it must be 

 packed immediately and stored in friction-top or sealed tin cans until 

 wanted for immediate use. The slices must be brittle in order to be 

 readily ground, and the ground product must be stored in tin to avoid 

 caking. 



TURNIPS 



Turnips are prepared for dehydration by the methods and with the 

 equipment used for carrots. They are sliced or cubed for general 

 purposes, or they may be shredded for soup mixtures. They should 

 be steam-processed. 



VEGETABLE-SOUP MIXTURES 



The individual vegetables making up soup mixtures are dried separ- 

 ately and mixed together in the proper portions after drying. The 

 formula may be varied somewhat, but potatoes usually comprise 

 about 40 to 60 percent of the mixture. Carrots, parsnips, tomatoes, 

 turnips, and cabbage are mixed in moderate quantity with a little 

 celery, onion, and spinach or parsley. 



UNITED STATES PATENTS 5 



1,132,020, March 16, 1915, W. M. Luther; fruit evaporator [with drying trays and 



controlled circulation]. 

 1,149,914, August 10, 1915, F. W. Haussermann; method of [drying and] preserving 



potatoes and other vegetables. 

 1,225,212, May 8, 1917, G. H. Benjamin; art of drying bodies [in a rotating drum, 



with controlled temperature, air circulation and lighting]. 

 1,259,774, March 19, 1918, T. J. Peters: apparatus for drying tomatoes and fruit. 



s A brief statement of contents (in brackets) is included in most cases in addition to the title as given in 

 the heading of the patent description. 



