French" is practically apricot-kernel oil, or a mixture of this with peach-kernel oil.1 The Soy bean (see p. 195), which grows in China and Japan, has been more recently cultivated in southern Europe and in the United States It contains 18 to 19 per cent. of oil, which is of such a good quality that it will no doubt come into more general use all over the world.2 This oil is one of the very few which can be used as a food and in paints and soaps. It is being imported to the extent of 200,000,000 pounds into the United States annually and is taking the place of large quantities of cotton-seed oil for domestic consumption. Tomato seeds have been recently employed, especially in Italy, as the source of an edible oil. An edible oil is also made from grape seeds.3 To the list above discussed may be added a large number of foreign nuts and fruits that yield oils and fats. Many of these are edible and are in common use by the natives of the respective countries where they grow. The methods used for extraction of the oils are so crude that the product is frequently of a much lower quality than if modern methods were used. Some of these oils are as follows:4 Cohune oil from the Cohune palm of Central and South America;5 Borneo tallow, from a fruit grown in Borneo; Mafura oil from the East African Coast; Kokum butter made from seeds grown in India; Sheanut oil, made from a seed grown in West Africa and used in making "margarine"; Butyracea fat, used in India for the adulteration of "ghee", Candle nut oil made from a seed grown in China and Australia; and rice oil, made from the rice bran. 1 Chem. Tech. Anal. of Oils, Fats and Waxes, Lewkowitsch, 5th. Ed., Vol. II., P. 323. 2 U. S. Dept. Agri., Farm. Bull. No. 372, 687. 3 Bull. Sci. Pharmacol (3), 26, 105-10; U. S. Dept. Agric., Bull., 632. 4 Fatty Foods; Bolton and Revis. 5 D. Cons. and T. Rep., 1914, p. 1323. CHAPTER XIII NUTS, AND NUT PRODUCTS Although in many countries some varieties of nuts have been used as food for a long period, in the United States, until comparatively recent years, the tendency has been to regard them as a luxury, or a confection, rather than as a food. Many of the nuts in common use, if compared in price with the more expensive forms of breakfast foods, are not an expensive food. While imported nuts were an expensive luxury, the native nuts, such as hickory nuts, walnuts, butternuts, chestnuts, hazel nuts and pecans, were formerly to be had by any one for the gathering; and in most parts of the United States this is still the case. Structure We recognize a nut as usually consisting of a somewhat oily meat or kernel, protected by a hard covering, the shell, and designed by nature as the seed for the propagation of the plant. The nut-bearing trees belong to various botanical families.1 Some are deciduous trees, as the chestnut, walnut, and hazelnut; others are pines or tropical palms; while others are even legumes. Nuts possess the advantage over many other foods, that the meat is well protected, and so they bear transportation, rough handling and low temperature. They deteriorate chiefly by becoming wormy, rancid or musty, but if kept cold they do not spoil rapidly. Composition Considering the composition of nuts, we find that the most abundant constituents are fat and protein, although in some there 1 Nuts and Their Use as Food, U. S. Dept. Agric., Farmers' Bull. No. 332. is an abundance of starch. As nuts usually contain but little water, they afford a very concentrated form of nutriment. Those having a high fat content-upward of 60 per cent.—are the pecan, brazil nut, butternut, filbert, candle nut, hickory nut, pine nut, and walnut. Those especially rich in protein-over 20 per cent.are the pignolia, a pine nut from Spain, peanut, butternut, almond, beechnut, candle nut, paradise nut, and pistachio. Those which are prized for their starch content-over 40 per cent.-are the acorn, chestnut, water chestnut, chufa (earth almond), and the ginkgo nut. Digestibility The digestibility of nuts has been quite extensively studied at various Agricultural Experiment Stations, notably that of California. If the true composition of nuts was better known and they were used understandingly, they would not have the reputation for indigestibility that they have obtained. As has been shown above, compared with ordinary foods, like meats which often contain 70 per cent. of water, they are a very concentrated form of nourishment, and so should not be eaten in large quantities, especially when the stomach has already been filled to repletion. We should look upon nuts as food, just as we are beginning to regard sugar as food, and use them as such in proper quantities and at the right time, and they will prove extremely valuable and occasion no discomfort. The experiments that have been made1 with fruit and nut diets seem to indicate that nut protein is about as easily, although possibly not as completely digested, as the proteins of bread and milk. It is true that a diet composed exclusively of fruits and nuts contains sufficient nutrients in the right proportion to support life, but experiments have shown that the protein from a mixed diet is more economically utilized than that from a single food, or a very limited variety. On this account those who use nuts in the place of meat should not depend upon nuts alone as the food 1 Loc. cit. supply, but use at the same time more bulky foods, with a low content of protein and fat. Comparing nuts for their fuel value,1 they may be arranged in the following order: roasted peanuts, unroasted peanuts, chufa nuts, almonds, pecans, English walnuts, filberts, hickory nuts and walnuts. The peanut on account of its high fuel value, and its cheapness, is one of the most useful nuts on the market. The fuel value per pound of nuts, as purchased, varies from peanuts 1775, to butternuts 385. Cooking Some nuts are improved in flavor and also rendered more digestible by cooking. In the United States the native chestnut, although often eaten raw, is much improved in flavor and digestibility by roasting or boiling. It is the cooked chestnut that finds favor as an important food material in Europe, especially in Italy and France. Chestnuts are often used for stuffing turkeys, and the combination of the starchy chestnut with the meat, which is rich in protein and fat, makes a well balanced ration. Nut Preparations Nut butters, especially peanut butter, on account of their agreeable taste and nutritive qualities, are coming into more general use as a substitute for ordinary butter. "Pastes" are also made from nuts with the addition of sugar. In the preparation of nuts for market, unshelled nuts like the pecan are often polished by rotating in revolving drums, and a little pigment or dye is sometimes added to improve the appearance, and make the nuts more salable. Nuts are also bleached by the use of sal soda, chloride of lime and water. These processes which in no way increase the food value of the product, are entirely unnecessary and add to the cost. The term "blanching" is applied to the method used in removing the skins from the kernels, as of almonds, by immersing 1 Proc. Ia. Acad. Sci. Vol. 10, p. 111. Compare, Rep. Me. Exp Sta., 1899, p. 87. them in boiling hot water and then rubbing off the thin coat thus loosened. Shelled nuts are at present very common on the market. As the meats are sometimes picked from the shells under most unsanitary conditions, and as dust and dirt are very liable to settle on them, they should be washed, preferably with hot water, before being used. Another use for nuts is in the making of coffee substitutes. Peanuts and acorns are generally used for this purpose; but only a small proportion of the nuts is soluble in hot water, so these beverages are not very nutritious. NUTS The following nuts are in common use in various parts of the world: Acorn; the fruit of various species of oak (Quercus). Almond; the fruit of the (Amygdalus communis) var. Dulcis and Amara. Beech nut; the fruit of the (Fagus sylvestris) or (F. Americana). Brazil nut; growing on the (Bertholletia excelsa). Chestnut; the fruit of the (Castanea dentata). Canarium nut, Pili nut, or Javanese almond (Canarium indicum) (C. ovatum). Chufa (earth almond), a bulbous root. Chinkapin; growing on the (Castanea pumila). Coconut; the fruit of the (Cocos nucifera). Ginkgo nut; the fruit of the (Ginkgo biloba). Hazelnut; the fruit of the (Corylus avellana, C. tubulosa, and C. grandis). Hickory nut; the fruit of the (Hicoria avata). Paradise nut; grown on the (Lecythis usitata). Peanut; a leguminous pod bearing the seed of the (Arachis hypogœa). |