FOOD MATERIALS 1020 



certain amount of "refuse." This is true in many foods, as apple and potato 

 parings, corn cobs, bones of meat, etc. 



Table I gives the percentage composition and the number of ounces of 

 foodstuffs per pound of some of our more common food materials. 



Discussion of Table I. — The data concerning these food materials 

 refer to each "as purchased." The first column under "per cent composi- 

 tion" gives the average amount of refuse to be expected from the food 

 indicated. It should be noted that the percentage of refuse is generally 

 high in meats, fish and fresh vegetables. The prepared food products, 

 such as butter, cheese, flours, sugar, contain little or no refuse; these are 

 the most concentrated foods that the ingenuity of man has produced. 



The percentages or proportions of water, protein, fat, carbohydrate 

 and mineral matter that make up the "edible portion" of foods are very 

 instructive. 



Every housewife knows, even if the chemist did not tell her, that fresh 

 fruits and vegetables contain the most water of any of our food materials, 

 but she may not realize that meats also contain the astonishing amount of 

 water indicated in the second column. 



Examination of the third and fourth columns shows that the animal 

 foods are essentially our protein and fat foods, with the cereal products a 

 close" second in proteins. Note, however, that olive oil, as well as refined 

 fat, is 100 per cent fat. 



The fifth column shows that animal foods, with the exception of milk 

 and cheese, contain no carbohydrate ; that the vegetable kingdom furnishes 

 our carbohydrate foodstuffs, with the cereal products containing from 50 

 to 75 per cent carbohydrate. 



The sixth column shows the percentages of mineral matter contained 

 in these foods. It should be noted that the high percentages of mineral 

 matter in bacon, butter, cheese, are due to the added salt in their manufac- 

 ture. Animal foods generally are more or less rich in mineral matter; but 

 the mineral matter contained in fruits and vegetables is considerable, and 

 seems best adapted to keep the body in health. Witness the dread disease, 

 scurvy, which ensues when vegetables are excluded from the diet. 



The number of ounces of foodstuffs per pound yielded by each food 

 material is given in columns 7 to 11. These data have been worked out in 

 terms of protein, fat, carbohydrate, mineral matter and the total. The 

 results are given for the convenience of the housewife who wishes to calcu- 

 late just how many ounces of the various foodstuffs, per pound of food 

 material, she is purchasing and is feeding to her family in any given length 

 of time. 



Fuel Value of Foodstuffs. — As has already been said, protein is essen- 

 tially a tissue builder, but it may be burned in the body as an energy food; 

 fats and carbohydrates are essentially energy foods. 



Just as the fuel value of coal is measured by the quantity of heat that 

 is given off when a given weight of it is burned, so the fuel value of a food- 



