FATS AND OILS 19 



11. Estimation of Amido -nitrogen in 

 Asparagine. (NH2.CO.CH2.CH(NH2).COOH.) 



One gram of asparagine is boiled with 20 c.c. of a 

 5 per cent, solution of hydrochloric acid for one and a half 

 hours with reflux condenser, the solution cooled, almost 

 neutralised with NagCOg, and transferred to an ammonia- 

 distilling apparatus (see Figs. 2 and 3, pp. 12, 13). Three 

 or 4 grams of magnesia are then added directly to the 

 liquid in the flask, and the ammonia distilled over 



N 

 into 30 c.c. — H2SO4 diluted with about an equal 



volume of water. 



After half an hour the receiving vessel is removed, 



the end of the delivery tube washed into it, and the 



N 

 excess of acid determined by titration with — alkali. 



N 

 The number of cubic centimetres of — acid neutralised 



2 



by the ammonia being obtained, the percentage of 



amido-nitrogen in asparagine can be calculated.' 



Asparagine contains half its nitrogen in the amido 



form, and the percentage of amido-nitrogen is therefore 



14x100 



— = 10-6. 



132 



NH2.CO.CH2.CH(NH2)COOH + H,0 



= C00H.CH2.CH(NH2).C60H + NH3. 



Aspartic acid. 



{c) Fats and Oils. 



12. Quantitative Estimation of Fat or Oil. 



The natural fats and oils (excluding the essential oils) are the 

 giycerides of the higher saturated or unsaturated fatty acids. 

 Owing to their high feeding value as producers of heat and 

 energy, the determination of the percentages of these compounds 



