Age-Old Uses of Seeds and Some New Ones

FREDERIC R. SENTI AND W. DAYTON MACLAY.

THE FOOD stored in seeds for their early growth also is food for people and animals.

Wheat is the world's bread grain. Rice is used almost entirely as food and is the main crop of southern Asia. Sorghum and millet are staples in parts of China and Africa. Corn is popular in South Africa and Latin America. Barley, rye, and oats also contribute to the world's food supply.

Nine-tenths of all seeds cultivated are cereal grains the breadstuffs of the world. By far the greater part of the food of all the people in the world consists of seeds.

Civilization developed in Egypt and Mesopotamia because of their favorable climate for cereal grains. The civilizations in ancient America were the product of those Indian races who knew best how to grow corn. Ceres was the Roman goddess of growing vegetation and her name we associate with grain cereals.

Legume seeds are the second great group of seeds we use for food. All kinds of beans, peas, and lentils supply protein. Dry, they contain 25 to 40 percent protein, and some are rich in carbohydrates.

Some legumes, such as soybeans and peanuts, are high in oil and protein, as are certain other seeds, particularly rape, sesame, and sunflower. Soybeans are 20 percent oil. Peanuts are 50 percent. Seed oils furnished about 55 percent of the world's edible oils and fats in 1959. (Nearly half the edible oils came from soybeans and peanuts.) Animal fats provided about 42 percent, and the marine oils provided 3 percent.

The soybean seed is the most important leguminous food in the world. In the United States, where half of the world crop is grown, soybeans are processed for their edible oil. The residue from soybean processing goes mainly into animal feeds.

Soybeans are extensively processed into a remarkable number of food products in the Orient. American chemists, seeking to increase exports of soybeans, have adapted modern techniques and fermentation methods to improve their use in such traditional Japanese foods as tofu and miso and in tempeh of Indonesia. Soybean flour, grits, flakes, "milk," and curd can be bought in the United States.

Peanuts are the world's second most important legume. They are used mainly for their oil. We produce peanut oil, but to a much greater extent we eat the entire seed. Blanched peanuts, as prepared for making peanut butter or for eating as nuts, are roasted seeds whose seedcoats have been rubbed off.

Cereal grains, supplemented with soybeans or dry edible peas or beans, comprise about two-thirds or three-fourths of the diet in parts of Asia and Africa.

In western Europe and North America, where the level of economic development is higher, grains and other seed products furnish less than one-third of the food consumed. Rather, meat and potatoes, sugar, and dairy products are the main sources of carbohydrate, protein, oils, and fats. People depend less on seeds for foods in Australia, New Zealand, and Argentina, where extensive grazing lands support sheep or cattle, and the consumption of meat is high.

Feeds for livestock took about one-sixth of the world's cereal crop in 1957-1958. Most of the grain is fed to swine and dairy cows and lesser amounts to beef cattle and poultry. About 90 percent of the corn used in the United States is fed to animals.

The rest is used for human food and industrial products. More than half of the sorghum and barley seeds we produce and most of the byproducts of the milling of cereals and the crushing of oilseeds are fed to livestock.

More than 200 million tons of seeds and seed products are fed to livestock annually in the United States.

The efficiency with which animals convert grains and forages to meat has risen steadily in the United States since the 1930's and has paralleled the increased feeding of the cake and meal that are a byproduct when seeds are processed for oil.

THE DEMAND for food is so great in the world that little arable land can be given over to growing the nonfood crops. Seeds grown for industrial uses hold a relatively minor position.

Chief among the seed crops grown primarily for industrial uses are the oil-bearing seeds flax, castor, tung (nuts from the China wood-oil tree), perilla (from an Oriental mint), and oiticica (from a Brazilian tree).

Oils, or liquid fats, from the seeds of flax and tung have long been the principal constituents of paints and varnishes for protecting and beautifying the surfaces of wood and metal. These oils develop hard, smooth films when they dry and form resinlike substances.

The artist who paints in oil uses drying oils to carry the pigments and to protect his finished work for the ages. One of the finest of artists' oils comes from poppy seeds.

Seeds of soybean, cotton, corn, sesame, and rape yield semi-drying oils. Some are used in paints along with drying oils. Palm oil protects the surfaces of steel sheets before they are plated with tin.

Castor oil, made from castorbeans, has gone out of style as a medicine. This nondrying oil, however, is now more in demand than ever before as a fine lubricant, as a constituent of fluids for hydraulically operated equipment, and as a source of chemicals to make plastics.

Almond oil, another nondrying oil, was once used extensively in perfumery to extract flower fragrances. It is still used in drugs and cosmetics, but it is rather scarce and sometimes is adulterated with oils from peach and plum seeds.

Liquid fats from all these oilseeds enter into the manufacture of soaps for industry and the household and of glycerin for such industrial uses as making explosives.

Sizable amounts of soybean, coconut, and palm kernel oil seed oils that are produced primarily for food purposes also are used to make soaps, detergents, and paint resins.

Solid fats from the seeds of the mahua tree, the Shea tree, and the coconut palm are used to make candles in tropical countries.

Seeds are a main source of starch for industrial and food use in many parts of the world. Corn and wheat supply most of the starch in the United States, Canada, and Australia. In other countries where cereal grains are not among the principal crops of a region, starchy tubers or roots are processed for starch. Starch is used in the paper, textile, and food-processing industries and in a multitude of other manufacturing operations.

Gums were extracted from quince, psyllium (fleawort), flax, and locust (carob) seeds in ancient times. Today the yearly import into the United States of locust bean gum is more than 15 million pounds; of psyllium seed, more than 2.6 million. The discovery during the Second World War that guar gum was similar to imported locust gum increased its cultivation in western Asia and initiated it in the United States.

Water-soluble gums are used in foods and drugs and in the manufacture of pulp and paper as thickeners, stabilizers, or dispersing agents. Guar gum thickens salad dressings and stabilizes ice cream. Quince seed gum is the main ingredient in wave-setting lotions. Once regarded as an agricultural nuisance, psyllium was sold in the 1930's as a mechanical laxative under 117 different brands. Locust gum is added to pulp slurries to break up the lumps of fibers in making paper.

THE SEEDS of hard, fibrous, stony fruits, called nuts, provide highly concentrated foods, oils, and other materials of value. Most nuts consist of the richly packaged storage kernel and its thick, adherent, brown covering the seedcoat.

The kernels of brazil nuts, cashews, coconuts, filberts, hazelnuts, hickory nuts, pecans, walnuts, and pine nuts are predominantly oily. Almonds and pistachio nuts are not so high in oil but are rich in protein. Chestnuts are starchy. All nut kernels are rich in protein.

The world production of familiar seed nuts almonds, brazil nuts, filberts, and the English walnuts totals about 300 thousand tons annually.

Coconuts, the fruit of the coconut palm, have the largest of all known seeds and are grown in South Pacific islands as a crop for domestic and export markets. The oil palm of West Africa yields edible oil from both the flesh and the seed or kernel of its fruit. World production of copra, the oil-bearing flesh of the coconut, was a little more than 3 million tons in 1959. Exports from producing countries in terms of equivalent oil were a little more than 1 million tons, about half of which was palm kernels or oil from them and about half was palm oil.

Other nuts consumed in lesser quantity include the spicy nutmeg; the soap nut, which owes its sudsing power to natural saponins; the marking nut, used for ink and varnish; the aromatic sassafras nut of South America; and the sweet-smelling cumara nut, which is suited for perfumes.

A forest crop that has not been extensively cultivated is ivory nuts from the tagua palm. The so-called vegetable ivory is the hard endosperm of the egg-sized seed. It is used for making buttons and other small, hard objects of turnery. Seeds of the sago palm are used in Bermuda to make heads and faces of dolls sold to tourists.

THE COLOR AND SHAPE of seeds have long made them attractive for ornaments and decorations.

Since Biblical times, rosaries have been made from jobs-tears the seeds of an Asiatic grass. Bead tree seeds are the necklaces of South Pacific islanders and the eyes of Buddha dolls in Cuba. Victorian ladies had a fad of stringing unusual seeds to wear as jewelry.

Handmade Christmas wreaths and trees often contain a variety of seeds collected during the year.

Tradition has assigned medicinal values to seeds because of their alkaloids, aromatic oils, and highly flavored components. Although science has given us more effective materials, preparations from anise, castorbean, colchicum, nux vomica, mustard, fennel, and stramonium are familiar to many for the relief of human ailments. Flaxseed poultices and mustard plasters still are used by some persons.

Peanut and sesame oils often are used as carriers or diluents for medicines administered by injection.

Still another group of seeds (sometimes tiny, dry, seed-bearing fruits) provide distinctive flavors and odors to foods, although the nutrients they supply are quite negligible. The common spices, flavorings, and condiments make up this group.

Each year millions of pounds of anise, caraway, mustard, celery, and coriander and the oils extracted from them are imported.