COMPARISON OF BEEF AND YEAST EXTRACTS. 7 



and peptones, which are valuable as food. The question of the pres- 

 ence of true peptones in these preparations is unsettled, though it is 

 difficult to understand how albumoses and amino acids can both be 

 present and no peptone. The dipeptid and polypeptid content of 

 these products have not been investigated, and as the peptones and 

 peptids are so closely related, if not identical, it seems justifiable to 

 consider that peptones are present at least to a slight extent in beef 

 extracts. 



SUMMARY. 



(1) The yeast extracts contain approximately 1 per cent of ether- 

 soluble material, the beef extracts larger amounts. No cholesterol 

 was found in the ether extracts. Sarcolactic acid was found in the 

 beef extracts examined, but not in the yeast samples. 



(2) The phosphorus of beef is largely water-soluble, consequently 

 a considerable per cent of the ash of beef extracts is composed of 

 this constituent. Approximately one-half of the sulphur of beef is 

 water-soluble. Yeast extracts derived from yeast rich in phosphorus 

 also contain a large amount in the ash. The total amount present 

 is larger than the ash content, showing that some phosphoric acid 

 is volatilized on ashing. The organic phosphorus determined by the 

 Siegfried-Singewald method gives approximately the 1 : 10 ratio 

 compared with the total as suggested by those authors. 



(3) The total nitrogen of the beef extracts on the water-free and 

 fat-free basis averages 11.82 per cent, that of the yeast extracts 

 averages 7.44 per cent. The amino nitrogen figures for the beef 

 preparations are nearly double those of the yeast extracts. 



(4) Although the water-soluble nitrogen of beef, which constitutes 

 25 per cent of the total nitrogen, consists of approximately two-thirds 

 protein and one-third amino nitrogen, the samples of beef extracts 

 analyzed average 72 per cent of amino nitrogen and 28 per cent of 

 protein nitrogen. 



(5) The general appearance and odor of the two varieties of ex- 

 tracts are very similar. As a food both are extremely limited in 

 value. The beef extracts contain more of the nitrogenous extractives 

 than the yeast preparations, otherwise their general composition is 

 much the same. 



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