Foods and Their Adulteration / Origin, Manufacture, and Composition of Food Products; Description of Common Adulterations, Food Standards, and National Food Laws and Regulations

by Harvey Washington Wiley

STARCHES USED AS FOODS.

Edible Starches.

—Attention has already been called to the fact that starch is the principal constituent of many of the common foods, such as cereals and the different varieties of the potato and other vegetables. Starch is often separated from the part of the plant producing it, and is then largely consumed as food in practically a pure state. Starches used in this way are presented in the form of pudding or desserts of some kind, and are often richly spiced, highly sweetened, and often eaten with cream. Starch also appears in the market under other names such as tapioca, arrowroot, etc.

Arrowroot.

—The plant which furnishes the substance known as arrowroot belongs to the natural family Cannaceæ and is principally native of tropical regions. The most important source of the arrowroot of commerce is the Canna indica. The starch of this plant exhibits in a strong degree certain characteristic qualities of starches derived from this natural family. The hilum in this starch is round and in some varieties double. The appearance of this starch under the microscope is shown in [Fig. 45]. The product of commerce is obtained from the rhizome and tubers.

Bermuda Arrowroot.

—The Bermuda arrowroot is obtained principally from the Maranta arundinacea. This arrowroot is also produced very largely in St. Vincent and other West Indian localities. The granules of the starch are very much smaller than in the two species just described. The hilum is prominent, and frequently takes the shape of a well defined slit instead of the usual round spot. These arrowroots and those of South African origin are very extensively used for invalid foods where starchy foods are indicated, which, however, is not very often the case. These starches form a firm and semitranslucent jelly-like body when heated to the boiling point in a small quantity of water. The term arrowroot is applied to starch from plants of the origin mentioned because the natives of the country producing them use the bruised rhizomes as a poultice for wounds caused by arrows.

Fig. 45.—Maranta (Arrowroot) Starch (× 200).—(Courtesy Bureau of Chemistry.)

Canna edulis.

—This species of Cannaceæ also furnishes a starch of commerce nearly allied to the Canna indica. The common commercial name of this variety of starch is “Tous les mois.” The starch granules of this species are rather larger than those of the Canna indica, and the concentric markings are more delicate and regular.

Madagascar Arrowroot.

—There is also produced in Madagascar an arrowroot from a different form of plant, namely Tacca pinnatifida. It is not, however, of any very great commercial importance. A similar starch is made from the same plant in Otaheite.

Plantain Meal.

—The plants of the natural family Musaceæ are important articles of food in many tropical regions, the plant yielding also, in addition to the starch, fibers suitable for textile use. The fruit of the Musa paradisiaca is chiefly employed for this purpose. It is quite similar in its character to the fruit of the allied species, Musa sapientum, or common banana. The starch granules which make up the plantain meal are remarkable for their long and narrow shape. The lines marking their surface are only faintly distinguishable, and the hilum is small and somewhat indistinct. Plantain meal is not used to any very great extent outside of the country where it is produced.

Fig. 46.—A Cassava Field in Georgia.—(Photograph by H. W. Wiley.)

Sago.

—Another form of starch which has a high value as a food product is made from the natural family Palmaceæ. The palm starch or sago is consumed in immense quantities in many parts of the world, and is probably in importance only second to the starch derived from the cereals as human food. The starch granules are rather large and coarse, although very many small granules are found mixed with them. Some of the larger granules appear to be partially divided or broken. The hilum is distinct and very long. The sago of commerce is like a tapioca made from the palm starch. It has been subjected to heat while still moist in the process of manufacture, so that it is quite difficult, as a rule, to find the distinct starch granules of the palm in the commercial article. Sago is grown principally in the Moluccas and Sumatra.

South African Arrowroot.

—There are many species of Marantaceæ cultivated in South Africa from which arrowroot is manufactured. They are of the same variety as that used in Bermuda and the West Indies. The cultivation of the plant has modified to some extent the action of the starch granules as originally found in the uncultivated plant. The starch granules in the cultivated variety approach more nearly a spherical form. The concentric lines are much more distinct and the hilum more prominent than in the wild variety.

Tapioca.

—The most important of the starch products used as food is the tapioca. It is made from the plant belonging to the natural family Euphorbiaceæ, and is derived particularly from the variety of cassava plant known as Manihot. Attention has been called to the fact that many of the varieties of cassava plant are highly poisonous, due to the natural development during growth of hydrocyanic acid, one of the most violent of known poisons. This substance, however, is of quite a volatile character, and when comminuted cassava root is heated or boiled, all or at least the principal part of the hydrocyanic acid (prussic acid) disappears. None of it or at least not more than a trace is found in the food product tapioca. A comparatively sweet variety of cassava that is containing but a small proportion of prussic acid is grown in Florida and Georgia. The appearance of a field of cassava is shown in [Fig. 46]. The tapioca of commerce is prepared by the separation of the starch in the usual way by grinding and washing with water. Before the starch becomes dry, in fact, while it is still containing its maximum degree of moisture, it is submitted to heat first at a low temperature, gradually increased until the starch granules are disintegrated or agglutinated into a somewhat firm and gelatinous mass. The heat is then continued at the proper temperature until the water is nearly all driven off. The starch from this plant is sometimes known as Brazilian arrowroot.

The starch granules of the bitter cassava are very small and often angular in shape, although some of them appear as well rounded spheroids. The hilum is, as a rule, clearly distinguished. The microscopic appearance of the grains of cassava starch is shown in [Fig. 47].

Adulteration of Tapioca.

—The true tapioca should only be made from starch of the cassava. Any starch, derived from any source whatever, if taken in the moist state may be subjected to the same process of heating, and forms an imitation tapioca which possesses many of the physical and probably all of the edible properties of the genuine article. The substitution, however, of any of the other starches for that of the cassava is at least an imitation, if not an adulteration, of the genuine article.

Fig. 47.—Cassava Starch (× 200).—(Courtesy Bureau of Chemistry.)

Food Starches Derived from Cereals.

—The starches which are derived from the common cereals are also extensively used as food products, especially the maize starch in the United States. It is commonly sold as “corn” starch, and is largely used for the purpose already mentioned. It may be in its natural state or it may be previously submitted to the action of heat while still moist, so that it takes on the character of tapioca or sago. In the United States the Indian corn is practically the only cereal which furnishes the food starch in very large quantities, although rye starch is extensively used for this purpose in other countries.

The starches of certain of the legumes, such as peas and beans, have also been separated and used for food purposes. They are not, however, used to any such extent as would warrant any especial reference to them at this point.

Starch from the Peanut.

—The peanut also yields a starch which has sometimes been separated and used for food purposes. The quantity so employed, however, is of no consequence as far as magnitude of product is concerned.

Food Starch Derived from the Potato.

—Potato starch is also used very extensively for food purposes, either in its natural form or when subjected to heat while still moist, as in the preparation of tapioca and sago.

Adulteration of Starches.

—The most common adulteration of starches is rather a misbranding than adulteration. The practice of adding inert white powdered mineral matters to starches is practically unknown in this country. Starch sometimes contains sulfurous acid used as a bleach in its preparation. This is an injurious substance and should be excluded from edible starches. The naming of a starch of one kind by the name of another and more valuable kind is simple deception. It is practiced to some extent in this and other countries. Starch itself may be used as an adulterant, as when maize starch is mixed with wheat flour or powdered starch mixed with granulated sugar. This kind of adulteration is quite unknown in this country. The selling of cheaper starches for tapioca and sago is more common than it should be.