SECTION VII. 



NITROGEN FREE COMPOUNDS. 



The compounds we are about to study are made up of the 

 elements carbon, oxygen and hydrogen, i. e. they are free from 

 nitrogen, and are called the nitrogen free compounds. These 

 compounds are nitrogen free extract, carbohydrates, crude fiber 

 and fats. 



Nitrogen Free Extract. — As previously stated the compounds 

 of this group are made up of carbon, hydrogen and oxygen. 

 There are a great many substances with which we are familiar 

 that come under this group of substances, such as starches, 

 various sugars, vegetable gums, and organic acids. The most 

 important group of nitrogen free extract substances are the 

 carbohydrates in which the hydrogen and oxygen are present 

 in the proportion of water, namely, two parts of hydrogen and 

 one of oxygen. The starches and sugars are the carbohydrates. 

 Potato starch and corn starch are some of the common starches. 

 Examples of the sugars are, the common white sugar (sucrose) 

 used at the table and corn syrup which sugar content is main- 

 ly glucose, and manufactured from starch. Various mixtures of 

 sucrose and glucose prevail among the sugars. Sucrose however 

 is the most important sugar as it is found in many of our plants 

 as sugar cane, sugar beet, sweet potato, corn plant, sorghum, 

 roots and some grasses. 



Vegetable Gums are found in beet pulp, gum arabic, wood 

 gum of wood and straw, and in the stems and leaves of plants. 

 Most, if not all, of our feed stuffs contain vegetable gums. 



Organic Acids occur in fruits, silage, and sour milk. Exam- 

 ples of these acids are citric acid of lemons, acetic acid of 

 vinegar, malic acid of apples, lactic acid of milk, and acetic and 

 lactic acids of silage. 



The nitrogen free extract is often termed carbohydrates al- 

 though from the previous statements we know that such practice 

 is not correct. The chemist determines nitrogen free extract by 

 subtracting the sum of the protein, fats, crude fiber, water and 

 ash from loo. 



