A textbook of domestic science for high schools

Fruits are composed largely of water ; their solids consist of carbohydrates, a small amount of protein, and some mineral matter. Although their food value is low, fruits form a very valuable addition to the diet, for they contain mineral matter in an organic form in which it can be readily absorbed by the system. Their organic acids have medicinal properties and can also be oxidized in the human system to provide heat and other forms of energy. Fruits differ from vegetables in that their carbohydrates are largely in the form of sugar, hence they can be eaten without cooking; cooking, however, softens the cellulose, thus making the fruit more digestible. Care and Preparation of Fruits. — The decay of fruits is due to the action of bacteria, their wilting to the loss of water; they should, therefore, be kept in a cool, dry place. Large fruits, as pears and peaches, should be wrapped separately in paper, that they may not be bruised. Fruits may be kept in good condition for some months by being placed in cold storage. As there is danger of harmful bacteria clinging to fruits, especially to those that have been transported long distances or that have been exposed to the dust of the streets, all fruit that is to be eaten raw should be first carefully washed. Dried fruits regain their original bulk and, in part, their flavor, when soaked in water, and they form a relatively cheap source of fruit supply during the winter months. Preserved fruits, jams, and jellies also form a valuable addition to the winter diet. Pectin. — Another constituent of fruits is pectin, which causes the juices to form a jelly when boiled with sugar. Pectin is a carbohydrate and is at its best when fruit is just ripe, or a little before it ripens. If fruit is overripe, or if the juice ferments, or if it is boiled too long with the sugar in making jelly, the pectin undergoes a chemical change and loses its power of jellying. Pectin will produce jelly only in the presence of a definite amount of organic acid, onehalf per cent of acid being about the amount required to make a good jelly; hence, fruits which contain but little acid must be made into jelly before they are ripe, or be cooked with acid fruits, or some lemon juice or cream of tartar be added to them. Identification Test for Pectin. — Mash the fruit, warm, and strain through a cheesecloth. Put a small amount of juice in a test tube and add an equal volume of alcohol ; shake well and let stand. The pectin will settle out in a gelatinous precipitate. EXPERIMENT 34. — Test various fruits, noting the amount and quality of the precipitate. Apples. — The apple is a native of Asia, the crab apple being the original or wild apple. The Romans used apples centuries ago. The apple is one of our most wholesome fruits, eaten either raw or cooked. Some of the best known varieties are named here. Cooking apples: Greening, Northern Spy, Baldwin, Maiden Blush. Eating apples: Snow, Bellflower, Rambo, etc. Apple Sauce Pare and slice 6 tart apples into a granite stewpan; add 1 c. water. Cover kettle and cook until apples are soft, add sugar and nutmeg to taste. Mash, or put through a colander as desired. % ts. butter may be added for flavor. Dried Apple Sauce