Page:Foods and their adulteration; origin, manufacture, and composition of food products; description of common adulterations, food standards, and national food laws and regulations (IA foodstheiradulte02wile).pdf/322

 from early in the spring until very late in the autumn. Immense quantities of peas are preserved by canning, and in this condition they retain their edible properties almost without impairment throughout the entire winter. The pea is valued as a food in many forms.

Composition.—

Percent. Percent. Percent. Percent. Percent. Percent.

Green pea,    79.93     .78      3.87     1.63     13.30        .49 Dry pea,      12.62    3.11     27.04     3.90     51.75       1.58

The above data show that the pea is a markedly nitrogenous food, especially the dry pea. Even in the green pea nearly four percent of its weight is protein.

A comparison of the composition of the pea with that of the bean shows that the pea is even more nitrogenous in character than the bean.

Potatoes.—One of the most important vegetables as well as food products in general is that class of products to which the term potato is given. The term strictly should apply only to that class known as white or Irish potato (Solanum tuberosum L.). The potato, as indicated by the name, belongs to a family of plants which is considered poisonous, but in the cultivated variety the poisonous principle has been practically eliminated. The potato belongs, essentially, to the starchy group of foods. If we assume, which is very nearly correct, that the average content of water in different varieties of potatoes at the time they are most suitable for edible purposes is 80 percent, it is found that at least three-fourths of the remaining solid dry matter is starch. The potato contains a trace of sugar and notable quantities of other carbohydrates than starch and sugar, namely, fiber. It also contains a very small proportion of nitrogen and mineral matter.

The potato is grown chiefly in temperate climates. It flourishes particularly well in the northern part of Europe, in England, Scotland, and Ireland, and in the northern portion of the United States. The northern part of Maine, especially, is noted for the production of potatoes of high edible qualities. It grows very well also in the southern part of the United States. The potato may be produced from seed, but that method of propagation has long since ceased to be practiced for agricultural purposes. The potatoes of commerce are produced from the eyes of the tubers. The best results in the growth of potatoes are secured in the loose somewhat sandy soil into which the roots of the plant can easily penetrate and which gives way readily to make place for the growing tuber. Hard, clay soils are unsuited to the growth of this vegetable. The planting is accomplished in the early spring after a thorough preparation of the seed bed by plowing to the usual depth, often subsoiling and reducing the surface of the soil to the proper tilth. The cuttings of potatoes or the whole potatoes are planted in rows to a depth of two or three inches, where they may sprout and even reach the surface at