MISCELLANEOUS PAPERS. 
129 
heated to 240 degrees Fahrenheit, a different product is the result, wholly 
unlike either the fresh or sun-dried fruit, and which will keep better, is more 
digestible and nutritious, is less acid, and will sell for more in the market. 
But if, after haying heated the air hot enough, there is not sufficient circula- 
tion, or the current not rapid enough the fruit will cook and then dry or burn 
the same as in a close oven. Apples will cook in boiling water of a tempera- 
ture of only 212 degrees Fahrenheit, or bake in an oven at 225 degrees 
Fahrenheit; but if the heated air circulates fast enough, the fruit will not 
cook or burn, or become itself heated to the temperature indicated by the 
thermometers, even at 300 degrees Fahrenheit, for the evaporation of the 
water is a cooling process and every particle of vapor leaving the minute 
cells which contained it carries with it also a large amount of caloric in a 
latent form and thus keeps the heat of the apples far below the surrounding 
air. The chemical change which belongs to truly evaporated fruit now begins, 
and the albumen instead of being slowly dried, coagulates precisely the same 
as in an egg when boiled. The soluble starch existing in all the fruit, and 
composed of CeHi0 5 will, if the heat is high enough, combine with one 
equivalent of water (ELO) so that now we have an entirely different com- 
bine, to wit, glucose, or fruit sugar, which will assist in the preservation of 
the fruit, instead of being liable to decomposition, as the dried starch is in 
the sun-dried or slowly dried product. 
“All the pectin or fruit jelly remains in the cells undecomposed, or is left 
upon the surface by the evaporation of the water in which it was dissolved, 
and may be seen condensed upon the surface, instead of being decomposed 
and passing on with the starch and gluten into the acetic fermentation. The 
diastase or saccharine ferment contained in all fruit, and which is the 
primary cause of its decay, has been rendered inoperative, and all germs of 
animal or vegetable life have been destroyed by the high heat. It is by this 
chemical change, which I have briefly described, in uniting a part of the water 
already contained in the fruit with the fruit starch, that these truly evaporated 
products are rendered more wholesome, more digestible, more indestruct- 
ible, and are thereby made more valuable, not only as articles of food, but 
because they are not subject to deterioration and loss. And it is also the 
reason why a bushel of apples will make more pounds of evaporated fruit 
than can be made by sun dfying it, as a portion of the contained water 
which would otherwise be lost is retained by combining with the starch to 
form glucose, and the carbonic acid, which is always lost in the slow de- 
composition resulting from sun-drying, is retained in its natural combination 
with the other substances composing the fruit, and hence is heavier. These 
profitable and healthful chemical changes which I have mentioned are all in 
accordance with the laws of nature, and are certain to take place if the 
necessary conditions of heat and air, as I have detailed them, are properly 
supplied, otherwise, you will have a different product, and no matter how fine 
your apples, how perfect your paring, caring and trimming, or how white you 
have bleached them, you have not made truly evaporated fruit, and no matter 
how many have been deceived by its color or full weight nr fancy packing, 
your fruit will not stand the test of long keeping in warm, damp weather. 
The natural starch, gluten and albumen of the fruit, instead of being cured or 
made indestructible by the chemical changes which constitute the difference 
between the evaporated and dried fruits, will absorb moisture from the air, 
will swell or increase in bulk, and can be attacked by mold, will absorb 
additional oxygen and finally sour and decay.” 
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