Human Foods and Their Nutritive Value Part 11

Occasionally they are used to such an extent as to mask the natural flavors of foods, and to conceal poor cooking and preparation or poor quality. For the microscopic study of spices the student is referred to Winton, "Microscopy of Vegetable Foods," and Leach, "Food Inspection and a.n.a.lysis."

205. Pepper.--Black and white pepper are the fruit of the pepper plant (_Piper nigrum_), a climbing perennial shrub which grows in the East and West Indies, the greatest production being in Sumatra. For the black pepper, the berry is picked before thoroughly ripe; for the white pepper, it is allowed to mature. White pepper has the black pericarp or hull removed. Pepper owes its properties to an alkaloid, piperine, and to a volatile oil. In the black pepper berries there is present ash to the extent of about 4.5 per cent, it ought not to be above 6.5 per cent; ether extract, including piperine and resin, not less than 6.5 per cent; crude fiber not more than 16 per cent; also some starch and nitrogenous material. The white pepper contains less ash and cellulose than the black pepper. Ground pepper is frequently grossly adulterated; common adulterants being: cracker crumbs, roasted nut sh.e.l.ls and fruit stones, charcoal, corn meal, pepper hulls, mustard hulls, and buckwheat middlings. The pepper berries wrinkle in drying, and this makes it difficult to remove the sand which may have adhered to them. An excessive amount of sand in the ash should be cla.s.sed as adulteration.

Adulterants in pepper are detected mainly by the use of the microscope.

The United States standard for pepper is: not more than 7 per cent total ash, 15 per cent fiber, and not less than 25 per cent starch and 6 per cent non-volatile ether extract.[71]

206. Cayenne.--Cayenne or red pepper is the fruit pod of a plant, _capsic.u.m_, of which there are several varieties,--the small-fruited kind, used to make cayenne or red pepper; and the tabasco sort, forming the basis of tabasco sauce. It is grown mainly in the tropics, and was used there as a condiment before the landing of Columbus, who took specimens back to Europe. Cayenne pepper contains 25 per cent of oil, about 7 per cent of ash, and a liberal amount of starch. The adulterants are usually of a starchy nature, as rice or corn meal, and the product is often colored with some red dye.

207. Mustard.--Mustard is the seed of the mustard plant, and is most often found in commerce in the ground form. The black or brown mustard has a very small seed and the most aroma. White mustard is much larger and is frequently used unground. For the ground mustard, only the interior of the seed is used, the husk being removed in the bolting.

Mustard contains a large amount of oil, part of which is usually expressed before grinding, and this is the form in which spice grinders buy it. In mustard flour there is: ash from 4 to 6 per cent, volatile oil from 0.5 to 2 per cent, fixed oil from 15 to 25 per cent, crude fiber from 2 to 5 per cent, alb.u.minoids from 35 to 45 per cent, and a little starch. The princ.i.p.al adulterants are wheat, corn, and rice flour. When these are used, the product is frequently colored with turmeric, a harmless vegetable coloring material.

208. Ginger.--Ginger is the rhizome or root of a reed-like plant (_Zingiber officinale_), native in tropical Asia, chiefly India. It is cultivated in nearly all tropical countries. When unground it usually occurs in two forms: dried with the epidermis, or with the epidermis removed, when it is called sc.r.a.ped ginger. Very frequently a coating of chalk is given, as a protection against the drug store beetle. Jamaica ginger is the best and most expensive. Cochin, sc.r.a.ped, African, and Calcutta ginger range in price in the order given. Ginger contains from 3.6 to 7.5 per cent of ash, from 1.5 to 3 per cent of volatile oil, and from 3 to 5.5 per cent of fixed oil. There is a large amount of starch.

The chief adulterants are rice, wheat, and potato starch, mustard hulls, exhausted ginger from ginger-ale and extract factories, sawdust and ground peanut-sh.e.l.ls, and turmeric is frequently used for coloring the product. The United States standard for ginger is not more than 42 per cent starch, 8 per cent fiber, and 6 per cent total ash.[71]

209. Cinnamon and Ca.s.sia.--The bark of several species of plants growing in tropical countries furnishes these spices. True cinnamon is a native of Ceylon, while the ca.s.sias are from Bengal and China. In this country there is more ca.s.sia used than cinnamon--cinnamon being rarely found except in drug stores. Ca.s.sia bark is much thicker than cinnamon bark. The ground spice contains about 1.5 per cent volatile oil and the same amount of fixed oil, 4 per cent of ash, and some fiber, nitrogenous matter, and starch. Cereals, cedar sawdust, ground nutsh.e.l.ls, oil meal, and cracker crumbs are the chief adulterants.

210. Cloves.--Cloves are the flower buds of an evergreen tree that grows in the tropics. These are picked by hand and dried in the sun. In the order of value, Penang, Sumatra, Amboyna, and Zanzibar furnish the chief varieties. Cloves rarely contain more than 8 per cent ash, or less than 10 per cent volatile oil and 4 per cent fixed oil, and 16 to 20 per cent of tannin-yielding bodies. No starch is present. The chief adulterants of ground cloves are spent cloves, allspice, and ground nutsh.e.l.ls. Clove stems are also sometimes used and may be detected by a microscopical examination, since they contain many thick-walled cells and much fibrous tissue.

211. Allspice.--Allspice, or pimento, is the fruit of an evergreen tree common in the West Indies. It is a small, dry, globular berry, two-celled, each cell having a single seed. Allspice contains about 2.5 per cent volatile oil, 4 per cent fixed oil, and 4.5 per cent ash.

Because of its cheapness, it is not generally adulterated, cereal starches being the most common adulterants.

212. Nutmeg.--Nutmeg is the interior kernel of the fruit of a tree growing in the East Indies. The fruit resembles a small pear. A fleshy mantle of crimson color, which is mace, envelopes the seed. Nutmeg contains about 2.2 per cent ash, 2.5 to 5 per cent volatile oil, and 25 to 35 per cent fixed oil. Mace has practically the same composition.

Extensive adulteration is seldom practiced. The white coating on the surface of the nutmeg is lime, used to prevent sprouting of the germ.

CHAPTER XIV

TEA, COFFEE, CHOCOLATE, AND COCOA

[Ill.u.s.tration: FIG. 53.--TEA LEAF. (After WINTON.)]

213. Tea is the prepared leaf of an evergreen shrub or small tree cultivated chiefly in China and j.a.pan. There are two varieties of plants. The a.s.samese, which requires a very moist, hot climate, yields in India and Ceylon about 400 pounds per acre, and may produce as high as 1000 pounds. From this plant a number of flushes or pickings are secured in a year. The Chinese plant grows in cooler climates and has a smaller, tougher, and darker leaf, which is more delicate than that of the a.s.samese and is usually made into green tea. The Chinese tea plant yields only four or five flushes a year. About 40 per cent of the tea used in this country comes from j.a.pan and 50 per cent from China. The tea industry of India and Ceylon has developed rapidly in late years, and is now second only to that of China. Tea has been raised upon a small scale in the United States. The quality or grade of the tea depends upon the leaves used and the method of curing.

214. Composition of Tea.--Black and green teas are produced from the same species of plant, but owe their difference in color as well as flavor and odor to methods of preparation. The same plant may yield several grades of both green and black tea. To produce black tea, the leaves are bruised to liberate the juices, allowed to ferment a short time, which develops the color, and then dried.[73] For green tea the fresh leaves are roasted or steamed, then rolled and dried as quickly as possible to prevent fermentation. The smaller leaves and the first picking produce the finest quality of tea. The characteristic flavor and odor of tea are imparted by a volatile oil, although the odor is sometimes altered by the tea being brought in contact with orange flowers, jessamine, or the fragrant olive. There are also present in tea an alkaloid, theine, which gives the peculiar physiological properties, and tannin, upon which depends largely the strength of the tea infusion.

The composition of tea is as follows:

=========================================== |ORIGINAL| GREEN | BLACK | TEA | TEA | TEA ------------------------------------------- Tannin, per cent | 12.91 | 10.64 | 4.89 Theine, per cent | 3.30 | 3.20 | 3.30 Ash, per cent | 4.97 | 4.92 | 4.93 Fiber, per cent | 10.44 | 10.06 | 10.07 Protein, per cent | 37.33 | 37.43 | 38.90 (all insoluble) | | | ===========================================

It will be noticed that green tea contains twice as much tannin as black tea; during the fermentation which the black tea undergoes, some of the tannin is decomposed. There is a large amount of protein in tea, but it is of no food value, because of its insolubility. About half of the ash is soluble. The tannin is readily soluble, and for this reason green tea especially should be infused for a very short time and never boiled.

Tannin in foods in large amounts may interfere with the normal digestion of the protein compounds, because it coagulates the alb.u.min and peptones after they have become soluble, and thus makes additional work for the digestive organs.

215. Judging Teas.--Teas are judged according to: (1) the tea as it appears prepared for market, (2) the infusion, and (3) the out-turn after infusion. The color should be uniform; if a black tea, it should be grayish black, not a dead black. The leaves should be uniform in size or grade. The quality and grade are dependent upon flavor, and, with the strength of the infusion, are determined by tasting. This work is rapidly done by the trained tea taster. The out-turn should be of one color; no bright green leaves should be present; evenness of make is judged by the out-turn. The flavor of a tea is largely a matter of personal judgment, but from a physiological point of view black teas are given the preference.

216. Adulteration of Tea.--A few years ago tea was quite extensively adulterated, but the strict regulation of the government regarding imported tea has greatly lessened adulteration. The most common form was the use of spent leaves, _i.e._ leaves which had been infused.

Leaves of the willow and other plants which resemble tea were also used, as well as large quant.i.ties of tea stems. Facing or coloring is also an adulteration, since it is done to give poor or damaged tea a brighter appearance. "Facing consists in treating leaves damaged in manufacture or which from age are inferior, with a mixture containing Prussian blue, turmeric, indigo, or plumbago to impart color or gloss, and with a fraudulent intent. There is no evidence that the facing agents are deleterious to health in the small quant.i.ties used, but as they are used for purposes of deception, they should be discouraged."[73] Facing and the addition of stems are the chief adulterations practiced at present.

217. Food Value and Physiological Properties of Tea.--Tea infusion does not contain sufficient nutrients to ent.i.tle it to be cla.s.sed as a food. It is with some persons a stimulant. The caffein or theine in tea is an alkaloid that has characteristic physiological properties. In doses of from three to five grains, according to the United States Dispensatory, "it produces peculiar wakefulness." Larger doses produce intense physical restlessness, mental anxiety, and obstinate sleeplessness. "It has no effect upon the motor nerves, but is believed to have a visible effect upon the sensatory nerves." (United States Dispensatory.) Experiments with animals show that it causes elevation of the arterial pressure. It is used as a cardiac stimulant. The quant.i.ty of theine consumed in a cup of tea is about 4/5 of a grain, or 1/4 of a medicinal dose.

[Ill.u.s.tration: FIG. 54.--COFFEE BERRIES.

1, Mocha; 2, Java; 3, Rio.]

218. Composition of Coffee.--The coffee tree is an evergreen cultivated in the tropics. It grows to a height of 30 feet, but when cultivated is kept pruned to from 6 to 10 feet. The fruit, which resembles a small cherry, with two seeds or coffee grains embedded in the pulp, is dried and the seeds removed, cleaned, and graded. Coffee has an entirely different composition from tea; it is characterized by a high per cent of fat and soluble carbohydrates, and also contains an essential oil and caffein, an alkaloid identical with theine. Tannic acid, not as free acid, is combined with caffein as a tannate.

====================================== |RAW COFFEE|ROASTED COFFEE -------------------------------------- | Per Cent | Per Cent Water | 11.23 | 1.15 Ash | 3.92 | 4.75 Fat | 12.27 | 14.48 Sugar, etc. | 0.66 | 8.55 Protein | 12.07 | 13.98 Caffein | 1.21 | 1.24 ======================================

The high per cent of sugar and other soluble carbohydrates in roasted coffee is caused by the action of heat upon the non-nitrogenous compounds. Coffee cannot be considered a food, because only a comparatively small amount of the nutrients are soluble and available.

It is a mildly stimulating beverage. With some individuals it appears to promote the digestive process, while with others its effect is not beneficial. Coffee is more extensively used in this country than tea, and is subject to greater adulteration. It is adulterated by facing and glazing; _i.e._ coloring the berries to resemble different grades and coating them with caramel and dextrine. Spent coffee grains and coffee that has been extracted without grinding are also used as adulterants.

Imitation berries made of rye, corn, or wheat paste, molded, colored with caramel, and baked have been found mixed with genuine coffee berries. Roasted cereals and chicory are used extensively to adulterate ground coffee. Chicory is prepared from the root of the chicory plant, which belongs to the same family as the dandelion. It is claimed by some that a small amount of chicory improves the flavor of coffee. However, when chicory is added to coffee, it should be so stated on the label and the amount used given. The dextrine and sugar used in glazing are browned or caramelized during roasting and impart a darker color to the infusion, making it appear better than it really is. The glazing also makes the coffee retain moisture which would otherwise be driven off during roasting. Coffee contains such a large per cent of oil that the berries generally float when thrown on water, while the imitation berries sink. Chicory also sinks rapidly and colors the water brown, while the coffee remains floating for some time.

There are three kinds of coffee in general use: Java, Mocha, and Rio or Brazil. The Brazil coffee has the largest berry and is usually styled by dealers as "low" or "low middlings." The Java coffee berries are smaller and paler in color, the better grades being brown. Mocha usually commands the highest price in commerce. The seeds are small and dark yellow before roasting.

219. Cereal Coffee Subst.i.tutes.

"A few of these preparations contain a little true coffee, but for the most part they appear to be made of parched grains of barley, wheat, etc., or of grain mixed with pea hulls, ground corncobs, or wheat middlings. It is said that barley or wheat parched, with a little mola.s.ses, in an ordinary oven, makes something indistinguishable in flavor from some of the cereal coffees on the market. If no coffee is used in the cereal preparations, the claim that they are not stimulating is probably true. As for the nutritive value, parching the cereals undoubtedly renders some of the carbohydrates soluble, and a part of this soluble matter pa.s.ses into the decoction, but the nutritive value of the infusion is hardly worth considering in the dietary."[56]

220. Cocoa and Chocolate Preparations.--Cocoa and chocolate are manufactured from the "cocoa bean," the seed of a tree native to tropical America. The beans are inclosed in a lemon-yellow, fleshy pod.

They are removed from the pulp, allowed to undergo fermentation, and dried by exposure to the air and light, which hardens them and gives them a red color. This method produces what is known as the "fermented cocoa." For the "unfermented cocoa," the beans are dried without undergoing fermentation. Fermentation removes much of the acidity and bitterness characteristic to the unfermented bean, and when properly regulated develops flavor. The original bean contains about 50 per cent fat, part of which is removed in preparing the cocoa. This fat is sold as cocoa b.u.t.ter. In the preparation of some brands of cocoa, alkalies, such as soda and potash, are used to form a combination with the fat to prevent its separating in oily globules. This treatment improves the appearance of the cocoa, but experiments show the alb.u.min to be somewhat less digestible and the soap-like product resulting not as valuable a food as the fat. Such preparations have a high per cent of ash. There is no objection from a nutritive point of view to a cocoa in which the fat separates in oily globules.

221. Composition of Cocoa.--The cocoa bean, when dried or roasted and freed from its husk and ground, is sold as cracked cocoa, or cocoa nibs.

From cocoa nibs the various cocoa and chocolate preparations are made.

Cocoas vary in composition according to the extent to which the fat is removed during the process of manufacture and the nature and extent to which other ingredients are added. An average cocoa contains about 20 per cent of proteids, and 30 per cent fat, also starch, sugar, gums, fiber, and ash, as well as theobromine, a material very similar to theine and caffein in tea and coffee, but not such an active stimulant.

Cocoa is not easily soluble, but it may be ground so fine that a long time is required for its sedimentation; or sugar or other soluble material may be added during the process of manufacture to increase the specific gravity of the liquid to such an extent that the same object is attained without such fine grinding. The first method is to be preferred. Cocoa and its preparations are richer in nutritive substances than tea and coffee and have this added advantage that both the soluble and insoluble portions become a part of the beverage. Owing to the small amount used for a cup of cocoa, independent of the milk it does not add much in the way of nutrients to the ration.

222. Chocolate.--Plain chocolate is prepared from cocoa nibs without "removal of the fat or other const.i.tuents except the germ." It differs in chemical composition from cocoa by containing more fat and less protein; it has nearly the same chemical composition as the cocoa nibs.

It is officially defined as containing "not more than 3 per cent of ash insoluble in water, 3-1/2 per cent of crude fiber and 9 per cent of starch, and less than 45 per cent cocoa fat."[71]

By the addition of sugar, sweet chocolates are made. They vary widely in composition according to the flavors and amounts of sugar added during their preparation. The average composition of cocoa nibs, standard cocoa, and plain chocolate is as follows:

============================================================== | COCOA | COMPOSITION OF | COMPOSITION OF | NIBS | STANDARD COCOA | PLAIN CHOCOLATE |--------------------------------------------- |Per Cent| Per Cent | Per Cent Water | 3.00 | -- | 3.09 Ash | 3.50 | 4.20 | 3.08 Theobromine | 1.00 | -- | -- Caffein | 0.50 | -- | -- Crude Protein | 12.00 | -- | -- Crude fiber | 2.50 | 5.02 | 2.63 Fat | 50.00 | 32.52 | 49.81 Starch and other| | | non-nitrogenous| | | matter | 27.50 | -- | -- ============================================================

223. Adulteration of Chocolate and Cocoa.--The various chocolate and cocoa preparations offer an enticing field for sophistication; they are not, however, so extensively adulterated as before the enforcement of national and state pure food laws. The most common adulterants are starch, cocoa sh.e.l.ls, and occasionally iron dioxid and other pigments to give color, also foreign fats to replace the fat removed and to give the required plasticity for molding.

224. Comparative Composition of Beverages.--Tea and coffee as beverages contain but little in the way of nutrients other than the cream and sugar used in them. The solid matter in tea and coffee infusions amounts to less than 1.2 per cent. When cocoa is made with milk, it is a beverage of high nutritive value due mainly to the milk.

COMPOSITION OF BEVERAGES[56]

============================================================================= | | | | | FUEL KIND OF BEVERAGE | WATER | PROTEIN | FAT | CARBO- | VALUE | | | | HYDRATES | PER LB.

------------------------|----------|----------|----------|----------|-------- | Per Cent | Per Cent | Per Cent | Per Cent |Calories Commercial cereal coffee| | | | | (0.5 ounce to | | | | | 1 pint water) | 98.2 | 0.2 | -- | 1.4 | 30 Parched corn coffee | | | | | (1.6 ounces to | | | | | 1 pint water) | 99.5 | 0.2 | -- | 0.5 | 13 Oatmeal water (1 ounce | | | | | to 1 pint water) | 99.7 | 0.3 | -- | 0.3 | 11 Coffee (1 ounce | | | | | 1 pint water) | 98.9 | 0.2 | -- | 0.7 | 16 Tea (0.5 ounce to | | | | | 1 pint water) | 99.5 | 0.2 | -- | 0.6 | 15 Cocoa (0.5 ounce to | | | | | 1 pint milk) | 84.5 | 3.8 | 4.7 | 6.0 | 365 Cocoa (0.5 ounce to | | | | | 1 pint water) | 97.1 | 0.6 | 0.9 | 1.1 | 65 Skimmed milk | 90.5 | 3.4 | 0.3 | 5.1 | 170 =============================================================================

CHAPTER XV

THE DIGESTIBILITY OF FOODS