Sugar. Acid.
Percent. Percent.
Blackberries, 5.78 .77 as malic
Cranberries, 1.52 2.34 " "
Currants, 6.70 2.24 " "
Grapes, 7.90-26.40 .59 " tartaric
Lemons, .37 5.39 " citric
Oranges, 5.65 1.35 " "
Peaches, 7.88 .56 " sulfuric
Pears, 9.11 .19 " malic
Pineapples, 11.50 .60 " sulfuric
Plums, 14.71 .77 " malic
Prunes, 16.11 .32 " "
Raspberries, 5.33 1.48 " "
Strawberries, 6.24 1.10 " "
In the above data the acidity is determined as malic acid in apples, blackberries, and strawberries, in which the predominant acid is malic. In cranberries one of the acids is benzoic, amounting sometimes to as much as 0.05 percent, in grapes tartaric, in lemons and oranges citric. In the other fruits where the character of the organic acid is not distinctly of one kind, the total organic acid is estimated as sulfuric acid (SO_{3}), not meaning by that, however, that the acids are present in the form of sulfuric acid but merely that their quantity was measured in terms of sulfuric acid.
Canned Fruits.
The industry devoted to canning fruits is of less importance in the United States than that identified with canned vegetables. Practically, nevertheless, every fruit which has been produced in this country has become a commercial article in the form of canned goods. With the exception of the method of preparation, the process of canning and other treatments are essentially the same as that of vegetables and therefore does not warrant any further description.
In the following data are found a brief description and the composition of the leading varieties of canned fruit:
Canned Cherries.—Cherries are one of the fruits which are valued for canning purposes. The pits may or may not be removed, according to the desire of the manufacturer and the demand of the consumer. The galvanic action which the cherry juice sets up on the tin plate tends to bleach the natural color of the cherry, and this action can be avoided by coating the interior of the can with a gum or some similar substance which entirely protects the metallic surface from contact with the juice of the fruit. When treated in this way the natural color of the cherry is preserved for a reasonable length of time.
Adulteration of Canned Cherries.—The only adulteration of canned cherries which is of any consequence is that which relates to artificial coloring. By reason of the tendency to bleach the color, mentioned above, it has been quite customary to add an artificial color to the cherry so that the red color may
