

AVAILABILITY AND FUEL VALUE OF FOOD MATERIALS. 93 
corresponding ether extracts are somewhat smaller. In esti- 
mating a factor for the heat of combustion of the fat in different 
kinds of food materials it may be assumed that the error intro- 
duced by the fact that ether extract represents other materials 
than fat which have a lower heat of combustion is offset by 
the incomplete extraction of fat, so that these two errors tend 
to compensate each other. In other words, taking the ether 
extract as a measure of the fat of food materials we may assume 
a heat of combustion of 9.5 caloties per gram for all animal 
foods except dairy products, the heat of combustion of which 
appears to be about 9.25 calories per gram, while the vegetable 
fats and oils may be assumed to have a heat of combustion of 
g.3 calories per gram. 
The heats of combustion of different kinds of fats and oils as 
found by various observers and the factors here assumed for the 
fat of different groups of food materials are shown in Table 7. 
AAR LEK: 
Average determined heat of combustion of fats and oils and assumed 
factors for fat of different groups of food materials. 



HEAT OF COMBUSTION 
PER GRAM. 

KIND OF MATERIAL. 
, Assumed 
Determined. | 6+ calculated. 


Calories. Calories. 


Beef fat, - - - - - = 4 - Qg.50 — 
Beef, ‘‘ ether extract,”’ . - H: : “ 9.24 — 
Mutton fat, - - - - - rm : Gust — 
Mutton, ‘‘ ether extract,’’ - - ~ - = 9.32 ere 
Pork fat; - - - - - - - : 9.50 — 
Pork, *‘ ether extract,” - . ‘ - 9.13 — 
Ar. L - = - - - - - 9.59 — 
Cottolene, - - - - - - 9.32 — 
Butter fat, = = - : = : : Q.27 — 
‘Wheat oil, - - - - - . -— 9.36 — 
Wheat, ‘‘ether extract,” - « : - ~ g.07 — 
Rye oil, - - - - ~ a - = Q.32 — 
yer). ether extract,” - ~ 2 - - 9.20 — 
Maize oil, - - - - - Ee = : 9.28 — 
Oats, ‘‘ether extract,” . - - - 8.93 = 
Barley, ‘‘ether extract,” - ete t= - - G07 = 
Nut oil (except cocoanut), es eae : é 9.49 — 
Olive oil, - - 2 = - - - - 9.47 aos 
Cocoanut oil, - = - ~ FS - - Q707 — 
Hato meat. ust, ¢ges, etc.,) . - - - - ae 9.50 
Fat of dairy products, - - - - . hae: 9.25 
Fat of cereals, - - - - - 2 ; = 9.30 
Fat of vegetables and fruits, = - - - - ie 9.30 


