Wright. — Nitrogenous Constituents of Meat-extracts. 



Art, II. — On certain Changes in the Composition of the Nitrogenous Con- 

 stituents oj Meat-extracts. 



By A. M. Wright, F.C.S. 



[Read bcjore the Philosophical Institute of Canterbury, 2nd November, 1910.] 



During the processes of manufacture of meat-extract considerable changes 

 in the composition of the nitrogenous constituents take place. In the first 

 place, the meat from which the extract is prepared is in contact with hot 

 water for some time, and this, in conjunction with the sarcolactic and other 

 flesh acids, and with the salts present in muscular tissue, causes a certain 

 amount of hydrolysis to take place. The collagen of the muscle-fibre on 

 hydrolysis yields gelatine, and by further hydrolysis soluble gelatin and 

 other gelatinoids ; similar action on the albumin yields small amounts of 

 albumoses. Secondly, during the concentration of the extract-liquor by 

 evaporation further changes in composition take place. 



A liquor showing the following analysis was concentrated : — 



Pel Cent. 



Moisture 



Organic matter 



Mineral salts 



Acidity, as lactic acid 



Total nitrogen 



Insoluble and coaguable proteids 



Proteoses 



Peptone-like bodies and polypeptides 



Total meat bases 



Ammonia . . . . 



Calculating these results to correspond with 



20 per cent, of watei-, the following composition is shown : — 



Moisture . . . . . . . . . . 20-00 



Organic matter . . . . . . . . 65-60 



Mineral salts . . . . . . . . 14-40 



Acidity, as lactic acid . . . . . . . . 8-00 



Total nitrogen . . . . . . . . 7-82 



Insoluble and coaguable proteids . . . . 2-65 



Proteoses .. .. .. .. .. 13-34 



Peptone-like bodies and polypeptides . . . . Nil 



Total meat bases . . . . . . .. 14-19 



Ammonia . . . . . . . . . . 0-85 



After concentrating the liquor in the usual way by open-pan evapora- 

 tion for forty-eight hours at 212° Fahr. the composition of the resulting 

 extract calculated on a 20-per-cent. -moisture basis is as follows : — 

 Moisture . . . . . . . . . . 20-00 



95-02 

 4-07 

 0-91 

 0-50 

 0-488 

 0-165 

 0-838 

 Nil 

 0-886 

 0-054 

 extract containing 



