541 UNIVERSITY OF ILLINOIS-COLLEGE OF SGI* 7 py l Stephen A. Forbes, Ph., D.Dean. DEPARTMENT OF CHEMISTRY ANALYSIS OF FOODS Coeps op Instruction in Chemistry. Arthur W. Palmer, Samuel W. Parr, Harry S. Grindley, Carleton ft. Rose, Clendon V. Miller, John L. Sammis, Robert W, Stark, Frank R, Frapril. James H. Walton, Jr. SPRINGFIELD. 11,1,.: Phillips Bros., State Printers 1899. Digitized by the Internet Archive in 2011 with funding from The Library ©fvGofligress http://www.archive.org/details/analysisoffoodsOOgrin ,*\ X V # THE NUTRITIVE VALUE AND COST OF FOODS. Food is a subject which at present is attracting much attention from all classes of people. It is a subject of vital importance to all, for the health, strength and welfare of human life largely depends upon the nutritive value and purity of foods. The best farmers of Illinois study carefully the best methods of feeding their farm animals. They know the composition of the different feeding stuffs and what foods to feed in order to produce fat, or what combination of foods to use for the best production of milk. They try to feed their cattle in a rational, scientific and economical manner. Is it not worth while to study carefully the nutrition of themselves and their families, as well as that of their live stock? Just as poor feeding stuffs produce only poo; farm animals, so poor human foods will produce people who are not capable of making the most and the best of themselves. We must learn more regarding the foods which we use. There can be no doubt that much of the disease of man is due to poor food, poor management in selecting the diet and to improper cooking of food. Further, man's ability to do work depends upon the food which he eats. A man that is fed upon a well selected diet which has been properly cooked can do more and better work, either mental or manual, than the man who has been supplied with food without regard to proper selection, and with a food improperly cooked. This is a fact which many of our people fail to realize but nevertheless it is true. Food for man, the cost of which makes up the large share of the cost of living of the great majority of people, and which has so much to do with the health and strength of every one is a subject of which a large proportion of our people have a very little definite knowledge. Is it not time that more at- tention should be given to this subject by the people of our State? In this country there has been expended much money, time and scientific labor in studying the foods used for animals, while the study of the foods used by man have been neglected and very little has been done upon a thorough study of such foods. However, tbis is a subject that from now on must and will re- ceive the attention which it deserves from our National and State Govern- ments, and our State Universities and Experiment Stations. Food of all kind serves two purposes in the body. In the first place it serves as fuel which burns in the body supplying heat for keeping up the temperature of the body and energy which is necessary for muscular and mental work. In the second place food supplies the body with material for building and repairing its tissues and fluids. In other words, the bones and the flesh of our body are made entirely from the food which we eat. From the same food we also obtain the energy to do both muscular and mental work. The body in some respects is like a machine which uses food for fuel. The body, like the machine, burns the fuel by the aid of the air, and as a result energy in the form of heat and motion is produced. However, the body differs from a machine, in the fact that the fuel, that is the food is used to build the body as well as to supply it with energy. This is not the case with the machine for it cannot be repaired by the fuel which it burns. In the ma- chine the fuel burns quickly giving carbon dioxide, water vapor and nitrogen which escape into the air, and at the same time those small portions of the 4 fuel which do not burn form ashes and cinders. In the human body carbon dioxide, water vapor and nitrogen are likewise produced by the burning of the food, but the combustion takes place much more slowly. The machine is- comparatively simple, constructed for one definite purpose; the human body, on the other hand, is most complex, and performs many different functions. Food materials as purchased consist of an edible portion and refuse. The edible portion comprises those parts which can be eaten, and include the flesh of meat, yolk and white of eggs, wheat flour and numerous other things which present themselves to our mind. The term "refuse" includes those parts of the food which can not be eaten, for example, bones, entrails, shells of oysters, bran of wheat, peelings of potatoes, and so forth. We make analyses of foods and feeding stuffs for the purpose of learning their value for nutriment and the proper ways to use them. In doing this,. we classify the food ingredient into different grotfps and give to each group a certain nutritive value. Although foods are so different in appearance,, chemical analysis shows that they are all made up of a comparatively small number of chemical compounds. These compounds are water and the so- called nutriments. In other words the edible portion of food is made up of water and nutritive ingredients, or nutrient. A nutrient is either a compound or a group of compounds which can be used by the body as food. The nutri- ents include protein or nitrogenous materials, fats, carbohydrates, and ash or mineral matter. As well known, examples of protein or the muscle-form- ing constituent of foods we have the gluten of wheat. The lean parts of meat and fish consists mostly of protein. The white of ee"g and casein of milk are other familiar examples of the nutrient protein. Fat is found abundantly in lard, fat meats and fat of milk or butter. It is also found as oil in corn, wheat and oats. As example of carbohydrates of food nutrients we may mention, the sugars and starches which occur in many grains and plants in large quan- tity but are found in meat and fish in only small amounts. The mineral matters which occur in foods consist of salts such as phosphate of lime and ordinary salt or sodium chloride. The first three classes of nutri- ents that is protein, fat and carbohydrates are all organic, that is they can be burned producing energy in the form of heat. In burning, these substances- are entirely changed into gases and leave no solid residue. On the other hand the mineral matters will not burn and are left behind as a residue when organic matter is burned. Now, let us consider for a few moments the part which each one of these nutrients play in nourishing the human body. Protein is the most expensive and the most important nutrient found in foods. The protein compounds are the only nutrients which contain nitrogen and they are therefore necessary for the repair of old and the building of new tissues. They are the material* out of which the greater part of the muscles of the body are formed. They are essential constituents of bones, tendons, nerve tissues, and all the vital fluids of the body. Every muscular and mental act of the body is carried on at the expense of some pix>tein material. In addition to all this work protein also produces heat. In order to satisfy these numerous demands for protein, the food of man must contain a liberal quantity of these nitrogen compounds. It has been shown by a number of dietaries made in this country that cur food as a rule do not contain enough of portein or flesh-forming substances. From these considerations, it is evident that we should make sure that a sufficient amount of this vital nutriment is always present in our foods. As we will see later, in studying Charts Nos. 2 and 3, lean meats and fish abound in protein. Cheese also contains a large quantity of protein. Among the vegetable foods beans, peas and oatmeal have a large proportion of protein. The nutrients known as fats and carbohydrates do not contain nitrogen. They are the heat producing foods. Starch, fat and sugar burn in the body and yield heat and power. A pound of starch, when it is completely digested by the body, produces the same amount of heat as if the starch were burned in a stove. The fats and carbohydrates not only produce heat but they may also form fat in the body which is stored as reserve fuel for future use. These nutrients alone can not produce muscle or sustain life because they do not contain nitrogen which is a necessary element of all life or living matter.. The mmerai matters or ash of foods are necessary food constituents. They are important because they assist in digestion, furnish material for the form- ation of bones and they also enter into the composition of all the vital fluids and every part and organ of the body. Tae facts which have been mentioned in the first few paragraphs of this paper may be more readily understood and fixed in the miud by referring to Chart 1, which is a reproduction of a chart prepared by Professor W. 0. Atwater, for the U. S. Department of Agricul- ture and published by the Office of Experiment Stations. Chart 1. nutrients of food and their uses in the body. Water. Edible Portion: Flesh of meat, yolk and white of eggs, wheat 1 r Protein. FOOD MATERIALS flour etc - Fats. AS PURCHASED. I . I Nutrients. \ Carbohydrates. I I Mineral I „ I Matters. Refuse: Bones, entrails, shells, J bran, etc. Protein— Forms tissue, -that is muscle, tendon and fat. 1 White of eggs, i. e., albumen, curd of milk, i. e., casein, lean meat, gluten of wheat, etc. Fats— Form fatty tissues. Fat of meat, butter, olive oil, oils of | All serve as fuel and yield corn and wheat, etc. I- energy in form of heat and muscular strength. Carbohydrates— Transformed into fat. Sugar, starch, etc. Mineral Matters— Aid in forming bone, assist in digestion, etc. Phosphate of lime, potash, soda, etc. .Food is that which taken into the body, builds tissue or yields energy. Food as was mentioned before serves two purposes. It supplies the body with material for building and repairing its tissues and fluids and it also serves as fuel which burns in the body supplying heat for keeping up the temperature of the body and producing energy for work. The value^of a food of the first purpose here mentioned is showned by its chemical composition, that is, by the amount of different nutrients which chemical analysis shows it to contain. However in order to show its value as a heat producing food it is necessary to make another determination. The power of foods to produce heat in the body is determined by burning them in a closed vessel called a calorimiter in such a way that all the heat is collected and the amount deter- mined exactly. For the purpose of comparing the heat producing powers of ■different foods we must select a unit of heat. The unit of heat usually taken is knowu as the calorie which roughly speaking is the quantity of heat re- quired to raise the temperature of one pound of water four degrees Fahrenheit. A pound of sugar or starch when burned under such conditions that all the heat is utalized will produce 1860 calories. In other words, a pound of sugar or a pound of starch if burned in such a manner that all the heat is used for warming water, would increase the temperature of 18G0 pounds of water four degrees Fahrenheit. A pound of fat will produce 4,225 heat units or calories; 2.25 times more heat thau a pound of starch. A pound of protein when burned in the body will produce the same amount of heat as a pound of starch, that is 1,860 calories. In determining the value of any food there is to be considered first its com- position, that it, will it furnish the proper amounts of nutrients needed by the system. In the next place, thei'e is to be considered the digestibility of food, that is the extent to which the nutrients are capable of being made use of when consumed as food. The palatability or agreeableness of the food to the taste and the price of food must also betaken into account. 6 The relative nutritive value of any food is shown by comparing its compos- ition with other foods. Charr 2, page 7 shows the composition of a number of the common food materials of Illinois in ordinary use. The different kinds of nutrients and non-nutrients are represented by bands and the broad black lines represent the number of calories of heat which the food is capable of furnishing to the body. It will be seen from this chart that as a rule the ani- mal foods and vegetables, that is fresh tomatoes, cabbage, onions, string beans, and so forth contain a large proportion of water while the cereals for example wheat flour, corn meal and rice contain only a small quantity of wa- ter and a large amount of nutrients. The meats are chiefly nitrogenous foods while the vegetable foods as a class are rich in carbohydrates. Cheese is a concentrated food containing much protein and considerable fat. Foods which haye the most fat and the least water have the highest fuel value. Butter and fat pork consist exclusively of fat and they therefore have the highest fuel value of any of the foods given here. Chart No. 3, also shows the composi- tion of the food materials of Illinois. Here however, the qualities of the dif- ferent constituents forming the food is expressed in per cents, that is as parts in one hundred parts of tha food. Thus beef round contains 7.26 per cent refuse, veal rib 19,00 per cent refuse, while milk, butter, wheat flour and so forth contain to refuse. Further beef round contains practically 61.00 per cent of water, fresh tomatoes 95.00 per cent while pure granulated sugar con- tains no water. CHART" 2 COMPOSITION OF THE FOOD MATERIALS OF ILLINOIS NUTRITIVE INGREDIENTS, REFUSE AND FUEL VALUE , NinRIEhTS . NON- NUTRIENTS FUEL VALUE ^^ ^^ PROTEin FATS CAPBO- MihERAL HYDRATES MATTERS EZZI3 n WATER REFUSE CALORIES NJTRIEMTS [TC P CT FUEL VALUE OF I LB Beef, rump Veal leg roost V///////, '////////////£ 10 20 30 40 50 60 70 80 90 400 600 1200 1600 2000 2400 2800 3200 3600 ft: Pork . hom roost ^^ Bocon E C'sco fisH Heri eggs y/////j=A\- Buttgr V/////////////k Cheese y /t=m -- M.lk ^^^tf^^^^^ Flour roller process ^SS^S^^ Oats rolled W/# m^ r---- W-------- ^ ------ Chart III. COMPOSITION OF THE FOOD MATERIALS OP ILLINOIS. Nutritive Ingredients, Be/use, and Fuel Value. Animal Poods. W CD Ms Pi CD 3 CD 4 6 r+ CD B* S3 C CD m Si CD £, h3 CD 8» H •=3 •C (3 cd a o ^ O.CD ■ Per ct. Per ct. Per ct. Per ct. Per ct. Per ct. Per ct. Per ct. 5.86 8.91 6.25 9.22 7.28 62.27 53.79 58.86 69.18 65.63 45.00 52.61 64.44 54.84 53.03 20.92 65.61 43.18 65.65 14.56 35.69 87.00 20^37 16.45 16.40 20.18 20.21 13.28 15.37 17.15 20.64 15.48 8.02 16.27 10.59 12.21 1.22 24.54 3.30 10.64 20.43 17.23 .76 3.11 32.69 11.09 7.89 20.41 24.57 61.34 7.57 4.82 9.05 80.90 34.50 4.00 2.45 2.99 5.00 .95 .77 .86 .99 1.32 9.99 .87 1.00 1.03 .79 3.78 .87 .57 .95 3.33 2.29 .70 31.96 37.65 34.49 21.93 27.09 55.96 27.33 26.04 42.08 40.84 73.14 24.71 15.98 22.21 85.45 64.32 13.00 833. 1172. 1033. 407. 553. 1626. Veal, leg roast 19.58 9.78 3.73 6.64 6.18 10.11 40.73 12.14 754. 652. 1245. 1625. 2738. 622. 400. 609. 3437 1948 Milk (average of American an- 325. VEGETABLE FOODS. 12.05 10.63 9.58 10.09 8.93 11.10 12.96 9.62 4.60 38.97 34.94 .22 13.66 13.56 9.44 15.31 12.38 15.94 11.25 12.19 17.25 10.13 10.80 1.10 1.80 3.95 7.84 1.67 .30 .13 11.08 11.35 .51 .57 72.71 71.90 75.54 64.82 75.40 71.73 75.44 64.24 65.26 49.18 51.91 99.68 .47 2.11 1.49 1.94 1.62 .93 .22 2.87 1.54 1.22 1.78 .10 87.94 89.37 90.42 89.91 91.07 88.90 87.04 90.38 95.40 61.03 65.06 99.78 1653 1666. 1747. 1821 1703- 1632. 1618 1889 2014. 1103 1190. 1854. VEGETABLES. 94.67 77.12 49.75 64.86 82.23 91.55 10.33 .37.86 1.01 1.33 .53 1.37 1.05 2.32 22.19 3.83 .22 .11 .05 .04 .07 .19 1.66 .32 3.64 4.41 1.53 11.41 8.14 5.20 62.27 7.66 .50 .64 .51 .71 .37 .76 3.55 .55 5.33 6.49 2.62 13.53 9.63 8.45 89.67 12.36 96 16.39 47.62 21.61 8.14 111 40 239 174 14S 1641. 49.79 227. FRUITS. Blackberries 87.15 82.86 76.82 75.77 56.35 59.49 89.07 81.95 46.15 56.41 1.29 1.83 .76 .57 .63 .21 .35 .59 .81 .72 .71 1.58 .11 .11 .10 .05 .31 .59 .41 10.39 13.10 7.94 12.56 5.66 6.48 10.02 16.60 14.21 6.77 .47 .64 .37 .39 .32 .17 .25 .27 .63 .31 12.85 17.14 9.18 13.63 6.71 6.91 10.93 18.05 16.06 7.80 247. 344 14.00 10.60 36.94 33.61 165. 249 121 Apples 127. Blueberries, canned 206. Huckleberries 345. 37.79 35.77 297 Oranges 139 9 In our work upon the study of foods at the University of Illinois, we have analyzed all these different kinds of food materials. In order that the results of the analysis of the common foods used may be more readily understood and fixed in the minds of those who are not familiar with the details of such work, we have prepared a collection of foods. The main part of the exhibit consists of what may be termed displayed analysis in which the starch, oil, water, and other substances contained in the food materials are shown in bottles. In this manner the actual constituents of wheat flour, bread, eggs, potatoes, meats and other foods may be seen at a glance. It will take only a few minutes to explain these analyses. The large bottle in Chart 4 contains 1,000 grams of rolled oats, from which, by chemical analysis, we have separated all of the four products in the proportion indi- cated by the quantities given in each one of the other bottles. From a quan- tity of rolled oats equivalent to that which is contained in the first bottle we have separated 648.2 grams of carbohydrates that is 64 82 per cent.' This quantity of starch is shown in the second bottle. Fromthe same quantity of rolled oats we have separated the quantity of protein shown in the third bottle. This represents 153.1 grams of protein or 15.31 per cent. That is 100 parts, or 100 pounds of rolled oats contain 15.3 parts, or 15.3 pounds of protein. In the same manner, by means of chemical analysis, the quantity of water contained in the fourth bottle has been removed from the 1,000 grams of rolled oats. The fifth bottle contains 78.4 grams of fat, which represents 7.8 per cent of the rolled oats. And if we should burn all of the rolled oats in the large jar there would be nothing left but the residue shown in the sixth bottle. This is the ash or mineral matter and it weighs only 19.4 grams, which is equivalent to 1.9 per cent. 10 In the same manner we have in Chart 5 the displayed analysis of corn meal. Notice the difference between the corn meal and rolled oats. 1,000 grams of corn meal contain only 39.5 grams of fat, while 1,000 grams of rolled oats contain 78.4 grams. There is twice as much in the case of rolled 11 oats. The differences in the quantities of pi*otein is also quite noticeable. In the case of rolled oats there is 153 grams of protein and only 94.4 grams in the corn meal. Ta the same way further comparisons of interest could be made but we have not the time at present to do so. 12 As far as chemical analysis is concerned the rolled oats is a more nutritious and valuable food than corn meal. But chemical analysis does not show all that is necessary regarding the desirability of one food above another. In all cases the individuality of the consumer must be taken into consideration. The food must have a pleasant taste and agree with the consumer. Some people can not eat some foods which are in every respect healthful and bene- ficial to most people. These are peculiarities which can not be accounted for at present. In determining the value of foods, the digestibility must also receive atten- tion. The value of food, for the support of the body depends not only upon the consumption and palatibility, but also upon the quantity of the nutrients which the body can take up from the food and use for its support. Thus far the University of Illinois has made no experiments upon the di- gestibility of the common foods of thjs state, but is now commencing an ex- tended study of the digestibility of the common foods of this State. The United States Department of Agriculture, under the direction of the Office of Experiment Stations and Prof. W. O. Atwater, has made a number of exper- iments upon the digestibility of milk, eggs, bread, potatoes and other animal and vegetable foods. From them some general deductions have deen drawn. Leaner meats are probably more easily digested than those containing more fat. Generally speaking, it has been found that the protein of vegetable foods is less digestible that that of animal foods. For instance, one-fourth or more of the protein of potatoes and beans may escape digestion and thus be useless for nourishment. It is ordinarily assumed that the small amount of carbohydrates in meat and fish is entirely digested. Carbohydrates other than fiber, which make up the larger part of the vegetable foods, are very digestible. The fat in both animal and vegetable foods differs in digestibility under varying conditions. Finally, in determining the value of a food we must also consider its cost. In determining the economical value of food materials we must compare their cost as bought with their composition or the quantities of nutrients which they contain. If a food contains only a small amount of nutrients that is protein, fat and carbohydrates, and is high in price, it is evident that it is not an economical food, but on the other hand it is really an expensive food. For example, in Chart 6 notice the price and composition of lemons. Here we obtain a very small quantity of nutrients and at the same time pay a high price for the same. Lemons at this price are an expensive food material. Foods which supply a large quantity of food constituents at a reasonable price are evidently cheap and of the greatest value from an economical standpoint. Again, referring to Chart 6, notice what a large quantity of nutrients are obtained for twenty-five cents from wheat flour, graham flour and corn meal. The cheapest food is that which supplies the most nutrient for the least money. The most economical food is that which is the cheapest and the same time best adapted to the wants of the body. Chart 6 shows the relative cost of the foods of Illinois and the amounts of nutrients obtained in different food materials for twenty-five cents. In the first place we have the name of the food, in the second column we have the price per pound of the food expressed in cents. In the third column we have the weight of the food expressed in pounds or decimals of a pound which could be obtained for twenty-five cents. In the fourth, fifth and sixth col- umns are given the weights of protein, fats and carbohydrates respectively, which would be obtained for the same amount of money. In the last column is given the fuel value expressed in calories. These figures represent the fuel value that is the power which the nutrients bought for the sum mentioned above have of furnishing the body with heat and energy. 13 Chart 6. RELATIVE COST OF THE FOODS OF ILLINOIS. Amounts of Nutrients Obtained in Different Food Materials for Twenty-five Cents. a ■a to o 3 Twenty-five Cents Will Buy. Kind of Food Material. i-3 m 2 l " i5 go £.0 : Cu o 2 5' 1 X a p a P < re Cents. Pounds. Pounds. Poi nds. Pounds. Calories. 10.0 13.0 10.0 10.0 10.0 8.3 13 1-1.0 2.3 25 16.0 3.0 6.1 3.0 6.1 2.0 8.3 8.3 5.0 5.0 .5 6.0 1.3 4.0 2.5 3.0 5.0 9.0 2.0 5.0 7.0 14.0 2.5 1.9 2.5 2.5 2.5 3.0 1.9 2.3 10.9 1.0 1.6 8.3 4.1 8.3 4.1 12.5 3.0 3.0 5 5.0 50.0 4.2 19.2 6.2 10.0 8.3 5.0 2.8 12.5 5.0 3.6 1.8 .49 .30 .34 .37 .52 .24 .42 .28 .36 .01 .39 1.13 .41 1.13 .44 1.18 .46 .34 .30 .41 .91 .35 .51 L.84 .63 .21 .44 .81 .55 .09 .02 .15 .02 .49 .24 .01 2160. 2288. 4457. 2162. 3143. 8220. 3440. 1400. .55 3549. Butter 3437. .05 6.03 2.02 5.97 2.13 9.44 1.94 2.26 5.00 .18 2.21 .06 1.19 .50 .52 .64 .52 .37 .86 .40 .45 .10 3149. 13721. 4612. 13820. 4^79. 21838. 5460. 4854. 9300. .05 .66 .02 .2« .07 .23 .32 .06 .05 .03 .04 .02 .01 .01 .05 .01 .01 .01 .02 .03 .04 .04 .01 .01 .01 .01 480. 5550. 16S. 4608. 1079. 1480. 1884. 1235. 963. 1688. 830. 896. 218. It is evident that at the prices given the fruits are the most expensive sources of protein and energy. For example look at the results in the case of rasp- berries, blackberries, apples, peaches, pears and lemons. Notice in all cases what a small weight of the nutrients that is protein, fat and carbohydrates we get for the sum of twenty-five cents. The next most expensive foods as judged by the results are the vegetables which, however, are not nearly as expensive as the fruits aud furnish for the same cost more protein and energy. The meats as a class of food furnish more protein and also a little more energy than most of the vegetables for the same amount of monev. However, the cereal foods are the least expensive and furnish much more energy and also more muscle-forming material. 14 In conclusion, I want to say if there are any members of this audience that are interested or would like to study this subject of foods, I advise them to send to the United States Department of Agriculture for the Farmer's Bulle- tins upon this subject. There is much to be learned from these bulletins and the Department is glad and also desirous of reaching as many people as possi- ble by this means. Further, if you are interested in this work I would be pleased to have you give me or send me your name and address or the name and address of any one that you know to be interested. The University of Illinois has now in press bulletins upon this subject that will be of much interest to the people of this State who wish to give more thought to this subject. H. S. Grindley, Associate Professor of Chemistry, University of Illinois. LIBRARY OF CONGRESS °014 338 190 £