THE CHEMISTRY OF FOOD

A MAN may eat his fill and yet be liungry. It i? not the' quantity but the proper quality in food that satisfies. It is not only true that what is one man's food is another's poison ; but it is also true that what is food at one season of the year, at one period of life, or in one climate, may be poison to the same individual at another season or age. or in another climate. The inhabitant of the tropic subsists and thrives on fruits on which the Ice- lander would starve ; while the blubber and oil that makes up the diet of the inhabitant of the frozen zones would be fatal to those who live under the burning sun of the equator. Even the same ]>erson requires a fmit diet in the tropics, and one of fats in the north region. The child requires food made up of different elements from that which best suits the adult; and the diet of a laborer in the open air must differ from that of the brain- worker, who takes little exercise, and wiiose work makes heavy draughts on the nervous system.

No one has luastered the art of cooking who does not know something of the chemical elements of foods, and the purpose they serve when taken into the system. It is particularly important that those who are compelled to practice rigid economy should know just what foods w^ill best supply the real needs of the family, and how the most real nourishment may be had for their money.

An adult takes into the system daily, through lungs and mouth, eight and a quarter pounds of dry food, water, and air necessary for respiration. The same amount is given off as waste througli the pores, lungs, kidneys, and intestines. Life and activity consume this amount &s fuel just as a lamp con* Bumes oil. Every movement, every breath, every heart-beat, every thought burns up a certain amount of fuel-material, and if the supply is not forth- coming, the machinery stops and death ensues. The better the oil the more perfect the light ; and the more perfectly the food is adapted to its wanta^ the more vigorous the body, and the more perfect the working of its intri- cate machinery of muscle, nerve, and brain.

Food is first masticated and then digested. In mastication it is not only moistened with saliva, but acted upon chemically in preparation for the more vigorous and thorough work or the stomach. It is a mistake to sup- pose that water or any of the various drinks taken at table are a substitute for saliva. They not only do not prepare food for the stomach, but force it into the stoniach unprepared, and, oesides, retard digestion by delaying tlie process until the water can be absorbed into the blood. For these rea- sons drinks should precede or follow a meal. Crusts of. bread and hard and firm food is wholesome, principally because it must be tlioroughly masti- cated before it can be swallowed.

When the food reaches the stomach it rouses into action, the gastric juice pours from hundreds of little points, the food is diluted and the more solv- ent parts dissolved, to be taken up by the thousands of little mouths which honeycomb the surface, and earned into the circulation to repair the waste of tissues. The oily jwrtions of food, and such as do not yiela to the action of the gastric juice, pass on and are subjected to the influence of the bile and pancreatic Huid, until all that is of value is absorbed, while the waste is rejected and passes off. (S92)

THE CHEMISTRY OF FOOD, 593

This mach of the digestive process needs to be known to make clear the Why of certain processes in cookery. As the juices of the stomach only act on the mrface of the food which passes into it, it is easy to see why light bread is more wholesome than heavy. The gastric and other juices can act only on the outside surface of a heavy lump of dough; but when made into light and porous bread, the outer surface is not only vastly increased, but the juices pour through thousands of avenues, and penetrate and act on every part. If the frugal housewife knew this, would she set the heavy, soggy loaf of bread before her children '*to save it?" Many a mother ig- norantly gives her child a stone when it asks for bread. • Fats of all kinds do not digest in tlie stomach. The gastric juice mingles with but does not dis.solve them. It is only after they have passed on and become subjected to the action of the bile and pancreatic fluid that they are taken up and made available as carbon for lung combustion. Fats, un- combined with other substances, act as emetics or cathartics and not as food. It is only when combined with other food that they are capable of being taken up by the absorbing vessels, and made to act as fuel to the system. A half pound of crude lard, unmixed with an^ other substance, would be rejected, but when thoroughly and skillfully mixed into a flakey crust will not derange the stomach, and will be assimilated and utilized. Remember that the use of more fat than can be perfectly blenrledy or any carelessness or imper* fection in the process, is sure to produce indigestion and work mischief.

Foods difTer in the time required for digestion. Some fruits refresh in- stantly, the juices being at once absorbed into the circulation. Some meats and vegetables yield almost immediately to the action of the gastric juice, and pass into the circulation. Others require a long time for digestion. The more subtle and delicate flavors and parts of food yield first ; then the «luten of the flour, the curd of the milk, the fiber of the flesh, reinforce the blood and supply muscular waste, while, later, the oily and sugary por- tions are worked over to repair waste or furnish fuel to keep up the heat of the body.

Food has chiefly two offices to perform : the repair of muscular waste, and the supply of the body with fuel to keep its heat up to 98**. Each of these is inaispensable to health and strength. The chief part of what ww eat is used by the lungs for fuel ; the rest, excepting small portions of min- eral substances, such as lime, potash, sulphur, etc., goes to the production of muscular and brain force. The great secret in the preparation of food that will prolong life and maintain a high state of health, is to adapt it to the peculiar conditions of those to be fed, — ^age, occupation, climate, and sea- son to be considered. Variety of food is nearly always at hand ; knowledge only is necessiiry to choose tliat best adapted to present needs.

The heat of the body is produced by the action of the lungs, which uses op the heat-producing food, as action of muscle or brain consumes the mus- cle-making material. The former is non-nitrogenous; the latter nitrogen- ous. Foods may be divided into three groups: the nitrogenous, in which nitrogen is the chief element, and which feed muscle oi)ly; the non-nitro- genous, chiefly carbon, which produce heat only ; and those in which both are united.

It has been proved by chemical analysis that the body requires four to five ounces for heat to one for muscle, and this gives us the key to the proper proportion of the elements in food, varying slightly, of course, with seasons, climates, occupation, and conditions.

The substance richest in nitrogen, the muscle-making element, is alba- men, found in its most perfect form in the white of an egg. The lean or Ted parts of beef, mutton, venis<m^ and chicken contain nearly as great a percentage^about fifteen per cent. The curd of milk, also, contains a largo percentage, as well as gram, pease, and beans. If muscles only were to be fed, these would be nearly perfect foods, but for one ounce that goes to tnuiscle, five canoes must go to heat, and this calls for carbon.

594 THE CHEMISTRY OF FOOD,

The carbon needed to keep up the bodily heat comes chiefly from starch, which is abundant in the vegetable kingdom. Grate a potato and wash in a succession of waters, allowing the sediment to deposit each time, and a floury substance will appear, perfectly white, and dry and crispy to the touch. This is starclt, and consists of round grains, too small to*^ be seen by the eye. One-half of the bulk of dry starch is cjirbon; the remainder is oxygen and hydrogen in exactly the proj>ortion as in water; and in that wonderful laboratory, the stomach, the carbon is eliminated from the starch, and the oxygen and hydrogen combine to form water.

The starch made fmm wheat is .seldom used as food. Sago, Tapioca, and arrowroot, so much uijcd fur puddings, are almost pure starch, with slight coloring matter taken from the niaterial. Corn starch is less agreeable in flavor, and makes a less firm jelly when cooked. These dessert dishes are eaj«ily digested, and contribute carbon, but do not feed muscle, except as thev are combined with milk, eggs, etc., in cooking, which contain a littie nitrogen and a good deal of carbon. This food, then, is not adapted to a working man or to growing children, who need to have their muscles fed. For persons of sedentary habits, especially for the aged, whose feebler res- piration needs a large supply of carbon to keep up beat, they are valuable oecause easily digested. For others they are of value only to supplement muscle-making footl as a dessert.

The following table (Prof. Yeomans) gives the proportion of starch in coni' mon grains:

Per Cent Starch Rice Flour, . . . 84 to a5 Indian Meal, . . . 77 to 80

Per Cent Starch. Barley Flour, . . . 67 to 70 ^Rye Flour, . . 60 to 61

Oat Meal, . . . . 70 to 80l Buckwheat, ... 52

Wheat Flour, . . . 39 to 77 1 Pease and Beans, . . 42 to 43

Potatoes (75 per cent water) 13 to 15.

The large variation in wheat flour is due to processes of grinding. Va- rieties of wheat only vary about five per cent, but the old process of mak- ing fine white flour, used only the middle or starchy parts of the kernel, rejecting the gluten (nitrogenous and muscle-feeding). The whitest and highest-priced flour was, therefore, least nourishing, containing the largest per cent of starch. Modern invention has, however, reversed this, and the best "new process" flour contains the largest proportion of gluten. The old argument in favor of Graham, that it contained a larger proportion of nitrogen, and better supplied the body with muscle-making material, no longer holds good. Analysis shows that the best "new process" flour and Graham are almost identical in these elements. The only advantage left for Graham is the action of the coarser particles of bran (the outer shell and indigestible} on the coatings of the stomach, which is often salutary, but ^metimes injurious to the delicate membranes. When flour and bread made from it contains one part nitrogen to four of carbon, it is nearly per- fect food, and will sustain li/e.

The substance which is of next importance in supplying carbon to the body is oil (which is chiefly carbon). The oils used for food are butter, lard, and fat of beef. Other oils, used sometimes in cooking, are nearly iden- tical with these. Thev contain about eighty per cent of carbon, butter hav- ing the least. In grains, oil varies, being nine per cent in corn meal, six in oatmeal, three and a half in rye, and one to two in wl-.eat. Oils and starch serve the same purjjose in the digestive process; both are useful to supply carbon; neither nourish muscle. Starch is easy of digestion, requir- ing one hour, while butter is converted into chvme in three and one-half, mutton-fat in four and a half, and beef-fat in five and a half hours. This furnishes the best of reasons why fats should be sparingly used, especially in warm and moderate weather, when asuflicient supplv of carbon is easily Becured from vegetable foods. Besides, it is a well established fact that ex- cessive use of fats in cooking cause an excessive secretion of bile, ar4 this^

THE CHEMISTRY OF FOOD. 595

In tarn, canses a sensation like hnnser and an increase of saliva. This is mistaken for real hunger. More food is taken, and indigestion and, later, dyspepsia result. An eminent authority says : **I believe it will be foupd the offending ingredient in nine-tenths of the dishes that disturb weak stem* achs." Dyspeptics need to reject not only foods in which fats are mixed, but those in which they are a natural element, such as the yolk of eggs, liver, milk, rich cheese, etc. Yolks contain twenty-eight per cent of ml, and milk over three per cent. One condition only calls for the use of fats in daily diet: Long-continued exposure to excessive cold. One pound of fat furnishes as much carbon as two and four-tenths pounds of starch, or seven and seven-tenths pounds lean meat. When the moisture of the breatb is converted to ice and freezes on the beard, the air has no watery vapor and is nearly |)ure, containing a large per cent of oxygen. To meet this in the lungs requires abundant carbon, and oils furnish this most readily.

The best bread for cold weather is that containing most oil. Corn bread ranks first, oatmeal next, rye third, and w^heat last. Of course compara- tively few are exposed to the rigors of winter in civilized life, and Ibrief exposure to cold is off-set by an increase of clothing, and ordinary diet fur- nishes a plentiful supply of carbon. For woodmen, soldiers, sailors, pilots, travelers, railroad men, and others exposed to long cold storms, especially when they can not exercise freely, should eat liberally of fat beef, yolks of <eggs, and butter. Butter is the least objectionable oi fats. Fat from salt pork and smoked bacon is less injurious than that from fresh pork. Beef fat IS also much more w^holesome than lard. Above all, let the cook remember that oils are physic, and next to poison, if not blended with substances which contain large quantities of starcn, such as rice, mealy potatoes, and bread made of fine wheat flour. An ounce of lard and a pound of flour thoroughly blended in a loaf of bread is digestible, but the same amount added to com meal (already rich in oil) would be fit food onl^ for a Greenlander. The proper proportion of oil in food in ordinary circumstances is illustrated in milk, which contains three and one-half parts oil in one hundred.

The next important element which supplies carbon is sugar, which is con- tained in greater or less quantity in aU vegetable' substances, and largely (five to six and one-half per cent) in milk. Sugar contains forty per cent carbon, the rest water. It seems to be first converted into fat, and then used in respiration. In moderate quantities it has no injurious effects. A part of sugar as ordinarily eaten passes into lactic acid, and aids digestion, but if too much is produced digestion is retarded.

There are two kinds of sugars in commerce, — cane and grape. The former is made from cane, maple sap, beets, corn-stalks, etc.; the other from plants which have an acid juice. Cane sugar contains twelve parts carbon to eleven of water; grape sugar twelve of carbon to fourteen of water. Sugars are changed by fermentation into carbonic acid and alcohol, but grape sugar is most liable to such fermentation, — cane sugar first becoming grape sugar by chemical combination with water. Pure cane sugar remains perfectly dry and unchanged in the air, while grape sugar attracts moisture, and becomes mealv and damp. Cane sugar dissolves more readily in water than grape, and hence tastes sweeter. Two jKJunds of cane sugar sweeten as much as five of grape. These facts give a hint to housekeepers of great value. Grape eugar, which is worth only two-fifths as much as cane, is used largely to adulterate the latter. The fine, floury "powdered" sugar is largely grape sugar, and is not only of much less value, but deteriorates more rapidly than pure cane sugar. Brown sugar, after standing for some time, absorbs water from the air, and becomes grape sugar. It is, therefore, the best economy to buy the best white granulated sugar.

There is another element of food wliich does not feed muscle, vegetable jelly called pectine. This and pectine acid particularly abounds in fruits and bernes. By the processes of ri5>enmg. tht\ vegetable'acids which aro en- closed in little c^lls, Xur^t ont, are diffused through the mass of fruit| and

596 THE OHEMISTBY OF FOOD.

manufacture pectine or jelly. Heat produces the same effect as ripening^ and cooking is, in fact, only a rapid process of ripening. This jelly, when combined with sugar, goes to make up a variety ot delicate articles, such as jellies and marmalades. They are nourishing, principally, on account of the sugar they contain, but are easily digested, cooling, and uelicious. It should be mentioned that nearly all fruits are rich in sugar, — a ripe peach contain- ing as much as an equal quantity of cane juice.

There are some other suhstances which a]ipear in less quantity in foods which seem none the less essential to huulth and life. One of these is phos- phorus, which is an element of brain and nerves, and is wasted by mental activity and nervous excitement. The brain-worker demands a diet rich in phosphorus, and in such a form us to be easily assimilated. The food that best sustains a laborer in the open air is not the best for those who live among the excitements and exhausting demands on the brain, that are the rule in city life. For the latter, eggs, most kinds of fish, oysters, lobsters, crabs, game, cheese, niul, among vegetables the potato; and these foods are just what are craved l»y city people.

Another element is sulphur, which is required in the growth of bone and cartilage, the hair and nails. Of this there is so much in the yolk of an egg^ that silver is blackened by contact with it. Curd of milk and cheese are also rich in sulphur.

Iron is alwavs present in healthy bipod, and its absence — paleness — is an indication of illness. Most articles of food contain iron ; in the juice of flesh, in eggs, and in milk it is abundant. Lime and salt arealso ingredients in all foooTthe fornier making bone, and the latter playing an important part in the creation of the digestive juices. Linui is found in all grains, particularly in wheat and in milk, in form of subphosphates. Bread and milk are for this reason an excellent diet for growing children, as they supply not only heat and nmscle, but lime that goes to supply the growth of bone. Salt also ex- ists in many articles of food.

Men and races grow in proportion to their skill in combining heat and muscle-producing foods. The hardy Scotch use oatmeal largely, which is rich in nitrogen. The Irish, who endure a large amount of hard labor on chea^ fare, eat potatoes, oatmeal, cabbage, and milk, while the lime and phosphates are said to be derived from the " hard" water impregnated with lime. The English add bacon (heat-producing) to beans, rich in nitrogen, and to rice, which abounds in starch (carbon), add milk and eggs, which feed muscle. The Italian eats macaroni, which is principally starch, with cheese, rich in nitrogen. The use of chemistry in cooking is to t«ach how to wpple- ment one kind of food by another which contains the essential elements which the first lacks. For Instance, venison contains fifteen per cent nitro- gen to fifty-two carbon, or as one to three and a half, while the ratio should be one to four or five. To make it perfect and satisfying food, we have only to supplement it with something rich in carbon, as wheat bread, oat- meal, potatoes, or rice. A farmer's dinner of salt pork and boiled cabbage is nearly perfect for an out-of-door laborer in cold weather. The cabbage is rich in nitrogen and the pork in carbon. It is a proper dinner dish, because it requires four and a half hours to digest, while a supper may be made on Tenison, which is digested in an hour. Beef has fifteen per cent of nitrogen, but is not so easily digested as venison, and is fit only for a breakfast or din- ner dish. Wheat bread does not contain nitrogen enough for a working- man's diet, and butter eaten with it does not supply the lack. Some kind of Jean meat is needed to make perfect food. The more active the life ou

THE CHEMISTRY OF FOOD. 597

to denseljMDOpulated coantries. A dozen large potatoes are equal to a pound of flour. Tne onion is very rich in nitrogen, — one onion being equal to three potatoes of ec^ual size in nutritive value.

Milk contains all the important elements of foo<l; yet adults need solid food. Add to milk eggs, rich in nitrogen, rice and sugar, rich in carbon, and you have a nutritiousdish, easily digested.

Butter-milk is a wholesome drink, particularly in summer, as the nutritive power of the milk is but little reduced by the removal of the butter, while the sourness, due to the formation of lactic acid, aids digestion.

Eggs contain a great deal of carbon, and are, for that reason, good food for cold weather. They are too concentrated for exclusive diet, and should be eaten with coarse food, or tliat which is composed largely of starch.

In making cakes, the oil of the yolks of eggs used makes the perfect bleni - ing of lard or butter imi>ossible, and hence unwholesome. For this reason aponge cake, which contains no butter, is' less objectionable.

Breads differ but little in these elements. Corn meal contains more oil and less nitrogen than others, and oatmeal is richest in nitrogen. The easy blending of the elements, and the tough gluten of wheat, make it tlie most available grain for bread. Wheat bread alone will support life longer than any other food except animal flesh. The proportion of nitrogen to car- bon is one to five, which is nearly correct for a sedentary person. For active, out-door life more nitrogen is needed, and is best supplied by lean meats.

The nutritive qualities of animals differ but little. Wild meats digest more easily than tame, though the time re<juired varies with the age and condition of the animal. Flesh is a stimulating diet because it is force-giv- ing and muscle-feeding. The animal has gathered from various sources and concentrated in its flesh the constituents which best meet the wants of our bodies in the most available form.

Applying the knowledge of the wants of the body, and of the elements of food to a bill of fare, and a wholesome breakfast aemands strength-giving and muscle-making food. Nothing is more quickly available than oee^teak, and it is most digestible broiled. It is a diet for real workers. Eggs are nutritive, but less stimulating. These provide for the muscles. For heat, starchy food is demanded, but bulk is not desirable for breakfast after a long fast. Bread and cakes of wheat flour are best for the purpose, and fruits, raw or cooked, furnish the mild vegetable acid, which aios digestion. If cof- fee is taken at all, breakfast is the time, so that the stimulating effect may pass away before the hour of rest comes. An infusion of genuine coffee, not a decoction, is not injurious in the morning to most persons, and is beneficial to those exposed to changes of temperature.

Nothing appeases the appetite sooner than the juice of flesh. The barley gives a color and flavor. Following soup is roast beef, which feeds the muscles, and after it come the puddings, which abound in carbon, to give the fuel necessary to keep up the animal heat. Last comes fruit to aid digestion, with its agreeable acids. In summer less carbon should appear on the bills of fare, and blanc manges, creams, fruit puddings and piej, berries, and ripe fruits should make up the desserts.

In making a feast, the wise hostess would consider well what has been the employment of the guests. A party of fox-hunters, or wood-choppers, or surveyors, would require an abundance of meats, but a collection of art- ists and scholars would relLsh better a variety of delicacies and novelties. A sleighing party will devour carbon, but those who have sweltered under a July sun long for cooline fruits and the leanest of meats. The time when a feast is given should decide whether food, easy or difficult of digestion, should appear on a bill of fare, though such consideration for the health of gueste 13 hardly to be expected of the average hostess.