CHEMICAL ANALYSIS OF FOODS 



11 



nutrients of foods are classified in the following 

 manner : 



Moisture. 



FOOD 



Dry Matter 



PROTEIN, 



Nitrogenous Matter 



or 

 Crude Albuminoids 



Non-nitrogenous 

 Matter 



[ALBUMINOIDS 



J (Proteids). 



^Amides. 



TOIL. 



CARBOHYDRATES. 



Fibre. 



Ash. 



The above nutrients are estimated as follows : 



Moisture. The finely ground food is heated in a 

 steam-oven till it ceases to lose weight ; the loss on 

 heating gives the amount of moisture in the food. 



A rapid method of estimating the moisture content of 

 cereal grains, etc., has recently been devised by Brown 

 and Duvel of America. With their patent moisture tester 

 the result may be obtained in half an hour. This is done 

 by taking a certain weight of grain, placing it in a 

 distillation flask with mineral oil, and distilling the 

 water off. The steam driven off in this way, after being 

 condensed, is led into a flask, which is graduated in 

 such a way that the moisture content can be read off at 

 once. The necessary temperature for distillation varies 

 from 170 C. to 190 C, according to the particular seed 

 or grain that is being tested. 



Nitrogenous Matter (Protein). A small quantity 

 of the finely ground food is taken and heated with 

 strong sulphuric acid to convert the organic nitrogen 

 into ammonia. Caustic soda is then added to the 

 solution, when the ammonia is distilled off and collected 



