Foods and Their Adulteration / Origin, Manufacture, and Composition of Food Products; Description of Common Adulterations, Food Standards, and National Food Laws and Regulations

by Harvey Washington Wiley

FRUITS.

Definition.

—Under the term “fruit” is included the edible products of many trees and shrubs. The term “fruit” in its general sense can be applied to any kind of a food product, as for instance the fruit of the farm, the fields, and the forest, but in a restricted sense, as it will be used here, it is applied to the class of orchard products represented by apples, peaches, pears, etc. Fruits, in a general sense, include also that class of wild or cultivated edible bodies known as berries. The term “berry” is restricted in its present sense to the products of certain small shrubs or vines, such as gooseberries, blackberries, raspberries, etc. The fruits that grow upon small bushes, such as the currant and gooseberry, occupy an intermediate position between the orchard fruits which have been mentioned and berries. Orchard fruits are conveniently divided into large and small fruits, the large fruits being represented by the apple, pear, peach, quince, etc., and the small fruit by the cherry and plum. Fruits were doubtless among the earliest foods of man, and this leads to another classification of fruits, namely, wild and cultivated. Wild fruits, at the present time, do not include any large proportion of human foods. There are certain trees growing wild, such as the mulberry, the wild cherry, and others, which produce delicious fruits, usually of small size. The term “fruit” as used herein does not include that very valuable class of foods known as nuts, which is considered under a separate classification.

General Characteristics of Fruits.

—The general characteristics of fruits include their color, flavor, odor, and nutritive properties in so far as we are concerned with them in this manual. They are composed very largely of water, perhaps 80 percent or more. The solid matter consists of the usual cellulose structure of vegetable bodies, sugars, gums, organic acids, and mineral matters. Fruits are all succulent, that is, by reason of their high content of water, composed chiefly of matters in solution which constitute their juices. All fruits, therefore, when subjected to pressure yield a juice which contains the principal portion of their dietetic constituents. The study of the composition of the fruit juices would, therefore, naturally accompany a study of the fruits themselves. The chief characteristics of fruit from a dietetic point of view and also a palatable standpoint are their sugars and acids. The characteristic of taste depends on these two constituents principally. In addition to this, the fruits contain aromatic substances belonging to the class of essential oils and compound ethers which give to them the agreeable odor which adds so much to their value. Fruits are naturally colored and these colors, to which the eye is accustomed, become marks of distinction and excellence in many cases. The prevailing colors of fruits are red, yellow, and green. All shades of colors, however, are represented by the mingling of the primary tints. Certain colors are associated with certain fruits as, for instance, red with the cherry, raspberry, etc., green, red, and yellow with apples, and shades of red and yellow with peaches. These colors are due to the different conditions of the chlorophyll or vegetable coloring matter which the skin of the fruit contains. The three principal color tints which are produced are known as chlorophyll, green, xanthophyll, yellow, and erythrophyll, red. The mingling of these three distinct colors in the plant coloring matter forms the various tints which are seen in fruits and which render them so attractive to the eye.

The sugars in fruit include both the common sugar (sucrose) and invert sugar, which contains equal quantities of dextrose and levulose. As the sugar is more or less abundant in proportion to the other ingredients the fruit is more or less sweet. The different fruits contain different quantities of sugar,—the richest perhaps is the grape which often in a state of complete maturity may have from 25 to 30 percent of sugar. Apples contain from five to 15 percent of sugar, and peaches and pears somewhat less. In fact this range in sugar will cover nearly all the fruits, large and small, as well as most of the berries. The quantity of sugar contained in each of the fruits will be especially noted in treating of them individually. One of the most important constituents of fruit from a palatable point of view is found in its organic acids. These vary in different classes of fruits. The most common organic acid in fruit is malic, which is the chief acid in the apple and allied forms. In citrus fruits, such as the lemon and orange, citric acid is the principal organic acid. In grapes the principal organic acid is tartaric. More than one of these acids is, however, usually contained in a single fruit, and other organic acids than those named are found in small quantities in various fruits. The three mentioned may be regarded as the typical acids in fruits. These acids, if prepared chemically and administered in a pure state, have practically no food value at all, and cannot be considered as wholesome material to place in the stomach. When, however, they are eaten in their natural state in combination with the potash and other bases which fruits contain, and mingled, as Nature has done, with the other constituents, they add not only to the palatability but also to the wholesomeness of the product. This is only another illustration of the fact that natural products are often wholesome and desirable where artificial products of the same kind chemically are hurtful and undesirable. Many fruits contain considerable quantities of a carbohydrate allied to some extent in its composition to sugar and starch but which has the property of setting to a semi-resilient mass known as jelly. This constituent in fruit is known as pectin or pectose and is present in greater or less quantities in almost all fruits. It is by the utilization of this component of fruit that the jellies which are so common an article of food are prepared. While in its physical properties the jelly of fruits has some resemblance to the gelatine or jelly of animals, its chemical composition and nutritive values are entirely different. The gelatine or jelly of animals is essentially a nitrogenous product while the pectin or jelly of fruit is essentially a carbohydrate product. The two, therefore, are not to be confounded.

Nutritive Uses.

—The edible fruits are not only valuable on account of the nourishment they contain but particularly so because of the general effect which they have upon the digestive operations. Their judicious use is conducive to health in many ways. The fruits are mildly laxative, as a rule, although there are some exceptions to this. For instance, in some berries, like the blackberry, the quantity of tannin present is sufficient to cause a styptic or binding action. While all the fruits contain tannin it is usually not in such proportions as to produce a constipating effect. On the other hand the combination of the acids, bases, pectins, and sugars favors a free and natural progress of the food through the alimentary canal. The entire withdrawal of fruit from the dietary, even if the nourishment it supplies be provided in some other way, would work great damage to health. There are certain dangers, however, to be avoided in the general use of fruit. Immature and imperfect fruits are unwholesome. Fruits are often subjected, moreover, to infection with eggs of various kinds of insects, and these organisms and the larvæ or eggs thereof may be introduced into the stomach with more or less injurious effects. In the eating of fruit, care should be exercised in the inspection and proper preparation of the article; it should be free from infection, decay, and insect life. The natural condition in which fruit is eaten is in the raw state, and in general it may be said that this is the more wholesome and preferable way of eating it. On the other hand the cooking of fruit sterilizes it and makes the consumer secure against any infection from bacteria and insect life, and in some ways promotes to a certain degree the digestive processes. This is especially true of fruits of a hard or unyielding nature. Cooked fruits, as a rule, may be considered less desirable than the natural article, but they deserve mention on account of their freedom from infection, wholesomeness, and general dietetic value. Some fruits, such as apples and pears, contain notable quantities of starch, especially in the immature state, and this disappears to a greater or less extent during the process of ripening. At the period of complete maturity the starch is reduced to a minimum and the sugar in the fruit reaches a maximum. After this period the fruit begins to lose in dietetic value, due to the natural process of decay, which is not even entirely checked by placing the fruit in cold storage. The sugar gradually ferments and disappears. The fruit becomes more spongy and less palatable and its general properties are impaired. Other fruits, such as the orange and lemon, berries, etc., contain little or no starch at any period of their growth. By careful storage the period of maturity may be prolonged for weeks or even months, and thus the fruit made available over a very much longer period than would otherwise be the case. Under the existing conditions of communication with all parts of the world it is not impracticable for even those who are not blest with wealth to have a daily supply of fresh fruits grown in different parts of the world. In temperate climes fresh fruits are available from June until May of the following year, either furnished directly from the orchard or properly preserved by storage.

Apples.

—The apple is one of the principal fruits in the market both for its crop value and for its general properties.