6r Tn the binrct test. Note carcfullv tin- color, which is dis- 

 tinctive for peptone-. Try the biuret te-t mi the same volume t a 

 dilute alliiiinin -..lution. in order t compare the color with that given 

 li\ peptone-. Kix carefully in \oiir mind the difference. 

 .. Kepcat experiment ?<i. Ke-ult ? 



Try al-o precipitation ly picric acid, tannic. acid. ()5'< 

 :ilo-h"l. sat. 1 1 -i 1 . .;'< CuS< >, and _" , lead acetate as before. 



isihility. Determine whether "Witte's 1'eptone" solution 

 \\ill ditl'u-c through parchment or colloilion within a period of two 

 hours. 



nipare in a tahle the reaction- of peptone and egg albumin. 



l\ . PLANT I'U( >TEINS. 



I'reparation of an <//M>/; ( >/-.S-<>//</'/<' protein (i/liadiin from 

 u heat tl< >ur. hi -ur o -ntain- chiefly starch, gliadin. glutenin. albumin. 

 -l"bulin. and a prok-.^e. l ; ..\amine some wheat flour under the 

 nik-p '-cope and apply the Iodine test. Result." 



i'S. Ap]>ly Millon'v te-t to flour in a test-tube. l\e-ult? 



< iliadin may be extracted by alcohol. To a -mall amount of 

 flour in a bottle add xnne (about y cc. I 70' > alcohol, and shake 

 at interval- during oiie hour. Then filter and u>e in the follouing 



ts. 



70. |-'.\ ;ipi >ratc a -mall portion in a di>h over the water bath, 

 the scales of gliadin. Are they -oluble in water? Determine 

 tin- by -baking with water in a te-t tube, removing the scales and 

 te-ting the water by the biuret te>t. 



-\. Adil icx ' alcohol in excess to a small amount of the 70'. 

 ale. 'hoi -nlutioii. |\e-ult ? 



7_*. I 'our -onie of the alcohol -olution of gliadin into water. 

 Result: 



7^. Meat to ln.ilin--. An\ coagnlati'ii? 



7). that gliadin differ- from egg albumin in many important 



pert-. Yet if i- a protein. Try the xanthoproteic and Millon's 

 te-t- with -OUH- dr\ gliadin -cale-. 



EXTRACTIVES 



'}(.-] llii- heal are included a large number of -nlistance- -uch 

 thi- alkaloid-. ghio>-jde-. ]igment-. purin bases, urea. etc.. too 

 nunii rmi- to be con-idered in detail in the laboratorv. 



is 



