


AVAILABILITY AND FUEL VALUE OF FOOD MATERIALS. 79 
for calculating protein from the nitrogen of frtits is found to 
be 5.80. 
_ In ordinary tables of percentage composition the values for 
protein in vegetables and fruits are calculated by use of the 
factor 6.25, which evidently gives too large results. It nat- 
urally follows that the figures for carbohydrates, which are 
obtained by difference, z. e., by subtracting the sum of the 
percentages of protein, fat, ash and water from 100, are too 
small by a corresponding amount. It is easy to compute the 
quantities of protein according to the factors above assumed 
from the quantities according to the factor 6.25 by multiplying 
by certain constant values. Thus protein as N. < 6.25 may be 
converted to protein as N. X 5.70 by multiplying by .g12 and 
to protein as N. X 6.00 by multiplying by ..g5o0. 
The following table gives the factors here proposed for cal- 
culating the amounts of protein in different groups of food 
materials from the total nitrogen. In addition the factors for 
changing protein as N. X 6.25 to protein as N. X 5.70, 6.00, 
etc., are given. Where protein is changed from one basis to 
another, however, the difference between the old and the new 
value must be added to the carbohydrates. 
, TABLE 2. 
Proposed nitrogen factors for the protein of different groups of 
food materials. 

Factors for computing 
Factors here protein according to 
KIND OF FooD MATERIAL. proposed. proposed factors from 
protein as N. X 6.25. 

Animal foods, 3 “ = - > 6.25 — 
Wheat, rye, barley, and their manufac- 
tured products, - - - - 5.70 .gI2 
Maize, oats, buckwheat, and rice, and 1 
their manufactured products, - - 6.00 . 960 
Dried seeds of legumes, - - - 6.25 — 
Vegetables, - - - - - - 5.65 . 904 
Fruits, - - . = - - - 5.80 .928 


FATS AND CARBOHYDRATES—FUEL INGREDIENTS. 
The fats and carbohydrates in the food may be considered 
together in view of their similarity of use in the body. ‘Their 
function is mainly that of fuel to yield energy for warmth and 
