go STORRS AGRICULTURAL EXPERIMENT STATION. 

The heats of combustion of vegetable proteids must be esti- 
mated largely from those of gluten, glutenin, gliadin, legumin, 
and plant fibrin, which are the principal proteid compounds. 
of vegetable origin of which we find the heats of combustion 
reported.* Asparagin may be taken as a type of the non- 
proteids of vegetable foods, with a heat of combustion of 3.45. 
calories per gram. ‘The heats of combustion of the protein of 
vegetable food materials will depend chiefly upon the propor- 
tions of proteids and non-proteids. In computing the heat of 
combustion of the protein of cereals we may assume 4 per cent. 
of the nitrogen of cereals as occurring in non-proteid com- 
pounds (see page 76). ‘The proteids of cereal foods may be 
assumed to have a heat of combustion of not far from 5.9 
calories per gram. In other words, about 96 per cent. of the 
weight of the protein of wheat flour, maize meal, buckwheat, 
etc., would have a‘total energy value of 5.9 calories per gram 
and the remaining 4 per cent. a value of 3.45 calories per 
gram. This would make the heat of combustion of one gram 
of protein of cereal food materials approximately 5.80 calories. 
per gram.+ 
Concerning the heat of combustion of the dried legumes we 
have little information. Assuming that 96 per cent. of the 
nitrogen of the dried legumes is in proteid and 4 per cent. in 
non-proteid combination, and that the heat of combustion of 
the proteids is that of samples of legumin which have been 
burned in the bomb calorimeter, namely, 5.8 calories per 
gram, we may assume the heat of combustion of one gram 
of protein of these materials to be not far from 5.70 calories. 
per gram. { 
a ee ee ee ee We * 

* See Table 6. 
+ The details of the computations are as follows: 
Ig. N. = .96 g. in proteids and .o4 g. in non-proteids. 
Then .96 x 5.70 = 5.47 g. proteids x 5.90 = - - 32.3 calories, 
and .04X* 4.70= .19 g. non-proteids x Rey ee .6 calories, 
or 5.66 g. protein = - - - - 32.9 calories, 
and I.oo g. protein = 5.81 calories. 
{ The details of the computations are as follows: 
Ig. N. = .96 g. in proteids and .o4 g. in non-proteids. 
Then .96 x 6.25 = 6.00 g. proteids x 5.80 = - - 34.8 calories, 
and .04xX4.70= .19 g. non-proteids x a5) === .6 calories, 
or §.6.19-g. protein = - - - A OSSRR calories, 
and 1.00 g, protein = 5.72 calories, 

