英文科學(xué)讀本 第六冊(cè)·Lesson 08 Plants Useful for Food (Ⅱ)

Lesson 08 Plants Useful for Food (Ⅱ)

Other Breadstuffs

The bean, pea, lentil, lupin, and vetch are included under the common name of pulse. They form a most useful class of breadstuffs, and enter largely into the food of both man and animals. The usefulness of pulse is due to the large amount of glutinous or tissue-forming matter which they contain; 100 lbs. weight of pulse averages about 24 lbs. of gluten.

The gluten of pulse is known as legumin. It resembles the gluten of oats rather than that of wheat. Pulse meal, although it is highly nutritious, will not make light, spongy bread, and in the countries where it is most eaten it is prepared in the form of cakes. The Scotch people, you remember, make their oatmeal into cakes; this, however, is not because they prefer close, heavy cakes to ordinary bread, but because the oatmeal will not make up into light, spongy loaves. Pulse meal alone would not make a good food, as it contains a very small percentage of fat. This perhaps will show you that it is no mere whim or accident that leads people to prepare a dish of bacon and beans. The fat of the bacon gives the very thing that is wanting in the beans, and the two together make an excellent food. On the same principle a mixture of beans and oats is found to make the best food for horses which are engaged in laborious work. The oats contain a large proportion of tissue-forming matter (about 16 percent), but they contain in addition an abundance of fat, which makes up for the deficiency of that material in the beans. On the other hand, the proportion of tissue-forming matter is much larger in the beans than in the oats. Thus a mixture of the foods gives more strength and endurance than either could give separately.

The common French or kidney bean is mostly eaten in the green state in this country. These beans are natives of India, but they are now grown in most temperate climates. The useful haricot-bean is simply the ripe seed of the French bean.

The broad or Windsor bean is not only grown largely for use as a green vegetable, but is imported in great quantities, in the ripe state, for feeding horses. In this state the beans are commonly known as horse-beans. Lentils make excellent soups, and they also yield a highly nutritious meal, from which is prepared the well-known food—revalenta—for infants and invalids.

There is a small kind of pulse grown in the East, and known as chickpea or gram. Travellers about to cross the deserts carry with them a supply of these peas, roasted ready for use. Heavy, bulky food would be an encumbrance; these peas are light and take up little room, while they are said to be more life-sustaining in their properties than any other food.

In Lombardy immense quantities of lupins are grown, and the meal which their seeds yield forms the staple food of the common people. The peanut or ground-nut belongs to the pulse family, and in the tropical regions where it is grown it forms the staple food for both man and animals. These nuts contain about 50 percent oil. We import ground-nuts into this country for the sake of the oil, which is worth from twenty to thirty shillings a ton, and is employed in soap-making. The residue left after expressing the oil forms a valuable oil-cake, worth from ￡8 to ￡10 a ton.

Sago, as you know, is obtained from the pith of the sago-palm. The tree, when mature, is cut down, and the pith, after being extracted, is washed in water on a sieve. The meal, which is mostly starch, settles at the bottom of the water, and is collected by draining off the water and drying in the sun.

The tree is cultivated widely throughout the tropics, but its natural home is New Guinea and certain parts of the coast of Arica. Here it forms the staple food of the natives, who bake the meal into a kind of bread or hard cake. Its importance to them as their chief breadstuff is seen from the fact that a fully-grown tree yields about 700 lbs. of sago-meal, while it is said that a healthy man can live on a diet of 2.5 lbs. of the meal daily.

The natives of the Pacific and Indian Archipelagoes depend almost entirely upon the breadfruit tree for their food supply. It yields a fruit which is to them what our wheaten loaf is to us. It is their bread.

This is a most wonderful tree, and affords a splendid illustration of Nature's lavish bounty in these regions. The fruit grows in such abundance that each tree bears and ripens crop after crop in succession during the year. Three trees are said to be sufficient to support a full-grown man for eight months out of the twelve. The fruit contains a porous and mealy pith, enclosed in a tough outer rind. It is usually plucked before it is quite ripe, and baked on hot stones. It tastes, when cooked, very much like wheaten bread.

To the natives of Central America, the West Indies, and other tropical parts, the banana or plantain is an equally important tree; it supplies their staple food. The fruit which it yields contains within its outer rind a mealy substance, which, when dried in the oven, resembles bread both in taste and composition. It is the bread of the people there.

In composition it is less nutritious than some of the other breadstuffs already named, as it contains only about 2 percent gluten mixed with about 20 percent starchy matter. The average daily allowance of food for a laborer in those regions is about 2 lbs. of the dry banana meal, with the addition of a quarter of a pound of fish or meat. This is said to afford ample sustenance. A single tree bears from 40 to 70, and sometimes 80 lbs. weight of fruit. Indeed no plant in the world is more prolific in its products than this tree. It has been calculated that 1000 square feet of land will produce, on the average, 462 lbs. of potatoes or 38 lbs. of wheat; but that same space will yield as much as 4000 lbs. of bananas, and in a shorter time.

The date is justly called the "bread of the desert." Its home is the northern part of Africa. Wherever a spring of water exists in those burning sandy deserts, the date-palm is sure to be found. Where every other crop fails, this tree will flourish in spite of the drought.

The people of the oases dry and pound the fruit into a kind of cake, and it becomes the bread of nineteen-twentieths of the population for the greater part of the year.