Arrow-Root. What is sold under this name in the shops, is a form of starch procured from the rootstocks of various species of plants belonging to the family Maran-tacea. There are three kinds of arrowroot known in the shops, the West Indian and the East Indian arrow-roots, and Tous les Mois. The West Indian is the produce of a species of Maranta, called M. arundinacea. The East Indian is produced by another species, the M. Indica. What is called Tous les Mois is obtained from another genus of Marantaceous plants, and is called Carina edulis. The part of the plant from which the starch is obtained is the same in all these cases, and the mode of preparation the same. Plants belonging to this family have what is called, botanically, a rhizoma or root-stock (a), an organ standing between the root and the stem. In this root-stock the starch is deposited, and it is separated in the following manner: - The root-stock is dug up, and then bruised and placed in water. The heavier parts, consisting of woody tissue and other matters, fall to the bottom of the water, but the starch is diffused through the water. The water, with the starch, is then separated, and allowed to stand, when at the end of some hours the starch falls to the bottom of the water ; it is then collected and dried. This is the principle on which all starch is separated from the tissues in which it is developed. By the same process starch may be procured from potatoes, carrots, turnips, and the stems, leaves, and seeds of plants.
Marania arundinacea - Arrow-Root.
Although arrow-root, sago, tapioca, and potato starch, are all composed of the same constituent, their flavour is very different; hence the preference given to arrow-root as an article of diet. This flavour depends on some peculiar principle which is produced in the plant from which the starch is obtained, and by very careful preparing can be entirely got rid of. Arrow-root is used for making cakes, puddings, and a thick gelatinous fluid in great request in the sick room. It is a property of starch to combine with water at a temperature of 180° and form a gelatinous compound. This property of starch renders it very useful in cookery, and seems to increase the digestibility of the starch itself.
Arrow-root is frequently regarded as very nutritious ; but if what we have stated above is correct, it will be seen that it is not nutritious in the proper sense of the word. Those foods can alone be called nutritious that contribute to the building up of the fabric of the body, by adding those materials to the tissues which are being constantly removed by the wear of the body. Now, starch does not perform this function, and is entirely consumed in the body in maintaining its animal heat. Arrow-root, however, and the other forms of starch, are frequently mixed with nutritious matters, such as milk and bread; and in this way the food into which they enter becomes nutritious.
Still, it may be said that children become fat when fed on arrow-root; and this is an undoubted fact. The explanation is, however, easy. When the carbonaceous substances are taken into the system in larger quantities than can be consumed in maintaining animal heat, they are changed in their characters, and become converted into oil, which being deposited in the tissues, produces fat. This oil is not a living part of the body; and a person may get fat even without having his frame nourished, or his strength increased. This is an important fact to bear in mind, as many persons get fat upon certain kinds of diet, without getting any stronger, or more able to perform the functions of the body.