COMPARISON OF BEEF AND YEAST EXTRACTS. & 



A. P. 796. A three and one-half year old grade Shorthorn, very thin. The 

 animal had been kept on maintenance rations for six months and was thin at 

 first. 



A. P. 797. A yearling grade Hereford in medium condition, i. e., a conditidu 

 for maximum growth without the laying on of fat. 



The two yeast extracts examined were prepared in England from 

 waste brewery yeast, the process of manufacture as observed by the 

 writer being as follows: Exhausted brewery yeast was thoroughly 

 washed in large vats with cold water to remove all of the beer and 

 impurities and was then heated to produce a rupture of the yeast cells, 

 after which it was evaporated in a vacuum cooker until the con- 

 sistency of a paste was reached. At this point the water content was 

 approximately 25 per cent. The extract in this consistency was 

 forced through pipes into suitable containers before cooling. Some-: 

 times these extracts were flavored with celery seed or other condi- 

 ments. While extracts prepared in this manner have the same general 

 appearance and odor as meat extracts, the color of the two extracts 

 examined was somewhat lighter than that of a typical beef extract, 

 and on careful comparison a difference in odor could be detected. 



METHODS OF ANALYSIS. 



The data reported in Table 1 were obtained as follows: The solids 

 were determined b}^ heating 2 grams of the extract in a platinum dish 

 for ten hours at TO C. in a vacuum of 26 inches. The samples were 

 heated in an electric muffle at low redness to determine the ash and the 

 chlorin was estimated by the Yolhard process. The phosphoric acid 

 was estimated by the Neumann method 5 and the usual volumetric 

 process. The organic phosphoric acid was determined according to 

 Siegfried and Singewald. c The ether extract was determined by the 

 official method. The insoluble nitrogen was not determined, as the 

 solutions of the extracts were practically clear. The total nitrogen 

 and the amino nitrogen were determined by T. C. Trescot, using the 

 Kjeldahl-Gunning process.^ The proteoses and peptones were sep- 

 arated from the amino bodies by the tannin salt method. 6 For purin 

 bases the modified Schittenhelm method f was employed. The krea- 

 tin and kreatinin were estimated by the author's modification of the 

 Benedict-Meyer methods The acidity was titrated with tenth- 

 normal sodium hydroxid, using a very dilute solution of the extracts 

 and phenolphthalein as the indicator. 



U. S. Dept. Agr., Bureau of Chemistry Bui. 107, Revised, p. 23. 



& Zts. physiol. Chem., 1902 37 : 115. 



c Loc. cit. 



a U. S. Dept. Agr., Bureau of Chemistry Bui. 107, Revised, p. 7. 



e U. S. Dept. Agr., Bureau of Chemistry Bui. 99, p. 182. 



f TJ. S. Dept. Agr., Bureau of Chemistry Bui. 114, p. 41. 



9 J. Amer. Chem. Soc., 1909, 81 : 692. 



