FRUIT AS FOOD 
ation by means of the oxydases present in 
the fruit of the tannin in the crushed 
cells. Such bruised portions contain a 
larger proportion of starch than the rest 
of the apple because the tannin hinders 
the transformation of starch into sugar. 
In investigations carried on at the Ore- 
gon Agricultural Experiment Station with 
a view to preventing the discoloration of 
evaporated fruits and vegetables, it was 
found that treating sliced apples with a 
weak solution of common salt (1 to 2 per 
cent) resulted in a product which was 
very bright and white and of better ap- 
pearance than that obtained by the well- 
known domestic method of treatment with 
cold water. It seems probable that the 
Oregon method may find application in 
the household. 
Fruits owe their flavor in considerable 
degree to the sugars and the malic, citric, 
and other acids which they contain, but 
the flavor which is so characteristic of 
different kinds is almost entirely due to 
ethereal bodies. The amount present is 
often too small for determination by the 
usual chemical methods. However, in 
many cases these flavor-giving bodies have 
been studied and their chemical nature 
is known. 
The flavor of strawberries has been 
shown to be dependent in part at least 
upon the presence of a volatile oil with 
pronounced strawberry odor which is 
found in small proportions in the extract- 
ed fat of the dried berries. Recent Ger- 
man investigators* have identified the 
compound ethers which give bananas their 
characteristic flavor. 
With the orange and other citrus fruits 
the oil found in the skin has a very char- 
acteristic odor and flavor which are al- 
ways associated in our minds with the 
flavor of the fruit. Obviously, the small 
amount of these bodies of pronounced odor 
and flavor can not materially modify the 
nutritive value of fruits, but they are of 
great importance in considering the place 
of fruit in the diet, as they are very 
largely responsible for its attractiveness 
and palatability. There is no doubt that 
we all eat more readily the foods which 
* Deut Essigindus, 1905, p 81. 
1037 
please our palate than those which are 
of indifferent flavor, and there is every 
reason to believe that the foods which 
please are actually digested more easily 
than those which do not, since they stimu- 
late a normal and abundant production 
of digestive juices. 
Composition of Fruits 
Determining the proportion of water, 
protein, fat, carbohydrates (nitrogen- 
free extract and crude fiber), and ash 
in fruits as in other foods furnishes a 
convenient basis for pudging of their rel- 
ative food value. It is quite common 
for chemists to determine, instead of 
their proximate constituents, the propor- 
tions of the different nitrogenous bodies 
present, as well as the amounts of the 
different sugars, etc., which in the ordi- 
nary method of analysis are grouped with 
the other carbohydrates. 
The more detailed analyses are of 
great interest and value for many rea- 
sons, but with our present knowledge 
it seems fair to assume that the vari- 
ous sugars and starches, for instance, 
have the same nutritive value, and so 
a knowledge of the total quantity of 
these bodies present gives very satisfac- 
tory data for estimating the food value 
of the group.* Very many analyses and 
studies of fruit and fruit products have 
been made by chemists of the agricul- 
tural experiment stations, as well as by 
the different Bureaus of the Department 
of Agriculture. Table 1 summarizes a 
large amount of such data and shows the 
composition of fresh, dried, and pre- 
served fruits and fruit products, and for 
comparison the composition of a few 
other foods as well. In this table and 
the discussions which follow, attention 
has been given especially to the fruit of 
northern and temperate regions and no 
attempt has been made to summarize the 
considerable amount of data available 
regarding tropical fruits, except some 
which are grown in the United States 
or which are fairly well known at least 
in the larger markets. Special studies of 
* An extended summary of the more detailed 
analyses of fruits and fruit products may be 
found in Konig’s Chemie der menschlichen 
Nahrungs und Genussmittel. Berlin, 19038, 
volume 1, fourth edition, pages 820-895. 
