2 COMPARISON OF BEEF AND YEAST EXTRACTS. 



etc. When, in the commercial manufacture of meat extracts, the 

 product is prepared from the liquor in which the meat for canning 

 is cooked the coagulable and insoluble protein is largely removed. 

 About 4 per cent of the beef consists of water-soluble protein, but a 

 portion of this is removed as coagulable protein on heating and 

 filtering. The amino bodies are water soluble ; also the mineral matter, 

 consisting largely of sodium, and potassium phosphates. It is evident 

 that all of the insoluble portions of the meat and some of the soluble 

 substances are not utilized in the process of manufacturing the 

 extract. The same is true to a more limited extent of yeast extracts. 

 The yeast used for extract manufacture has a varying water content, 

 which averages 75 per cent. The organic matter consists of albumins, 

 nucleoproteins, etc. The nucleoproteins are split during the manu- 

 facturing process into nucleic acid and protein, and the nucleic acid 

 is further broken up into xanthin bases, pyrimidin bases, and phos- 

 phoric acid. Both varieties of extracts are generally considered to 

 be valuable because of their flavoring and stimulating action rather 

 than because they possess any marked food value. It is rather diffi- 

 cult to judge of the age of an extract, and Siegfried and Singewald 

 have suggested that this can be done by determining the relation of 

 the total to the organic phosphorus, the organic phosphorus being 

 highest in the fresh extract, where it comprises one-tenth of the t'otal 

 phosphoric acid. 



DESCRIPTION OF SAMPLES. 



The beef extracts, the analyses of which are here reported, were 

 obtained from P. F. Trowbridge, of the Missouri Agricultural Ex- 

 periment Station. They were prepared as follows : Five kilos of lean 

 round beef were thoroughly ground and mixed, then extracted, washed 

 with cold neutral water, and finally squeezed through cheese cloth. 

 This process was repeated from eight to ten times, until the last wash- 

 ing gave no Biuret reaction. The filtrates were united, filtered, and 

 concentrated on the water bath. The coagulum was removed by fil- 

 tration several times and the evaporation continued until the extract 

 became a semisolid mass, when it was placed in sample bottles for 

 analysis. No preservative was added, the per cent of salts present 

 being sufficient to prevent any decomposition of the sample. Mr. 

 Trowbridge reports the condition of the animals from which the 

 samples were obtained as follows : 



A. P. 794. A grade Hereford one and one-half years old and thin; for six 

 months had been held to a slow gain of one-half pound per day and at the time 

 of slaughter was better than medium, but not fat enough for prime beef. 



A. P. 795. An old bull, sample of round, from Swift & Co., Kansas City. 



Zts. Nahr. Genussm., 1905, 10 : 521. 



