3 Transactions. 



It is thus apparent that some considerable change had taken place in 

 the composition of the material. 



A portion of the same original liquor was concentrated under a partial 

 vacuum of 15 in. at 180° Fahr. for three hours and a half, and the com- 

 position of the resulting extract calculated to a 20-per-cent.-moisture con- 

 tent shows : — Per Cent. 

 Moisture .. .. •• •• .. 2(>0() 



Organic matter . . . . . . . . 63-04 



Mineral salts . . . . . . . . 16-96 



Acidity, as lactic acid . . . . . . . . 8-20 



Total nitrogen . . . . . . . . 7-86 



Insoluble and coaguable proteids . . . . 2-63 



Proteoses . . . . . . . . . . 13-08 



Peptone-like bodies and polypeptides . . . . 0-31 



Total meat bases . . . . . . . . 13-76 



Ammonia . . . . . . . . . . 1-08 



It is seen that when the liquor is evaporated under vacuum there is 

 some change in the composition of the resulting extract — the proportion 

 of the organic matter decreases, while the mineral salts increase ; other- 

 wise the composition of the vacuum-evaporated extract is very nearly 

 that of the original liquor calculated to a 20-per-cent. -moisture content, 

 the acidity, insoluble and coaguable proteids, proteoses, and total meat 

 bases being present in about the same amounts in each case. In the original 

 liquor there were no peptone-like bodies, whereas in the vacuum-con- 

 centrated extract there were found 0-31 per cent, of these substances. 



The extract concentrated in the open pan is very different in composi- 

 tion from either the original liquor or the vacuum extract : the proportion 

 of the organic matter has decreased, and the mineral salts increased con- 

 siderably ; the total nitrogen remains about the same, but the forms in 

 which the nitrogen is present have undergone considerable change ; about 

 three-fifths of the insoluble and coaguable proteids have been rendered 

 soluble and converted to other nitrogenous substances ; there is a decrease 

 in the amounts of proteoses and meat bases ; while against these decreases 

 there is found 8-69 per cent, of peptone-like bodies which are absent in the 

 original liquor, and present in the vacuum extract to only 0-31 per cent. 

 The acidity has increased by over 2 per cent. 



The peptone-like bodies and polypeptides are bitter in taste, and it is 

 found that extracts containing relatively large amounts of these bodies 

 have a decidedly bitter taste. Samples containing 16-58 per cent., 12-02 per 

 cent., 14-65 per cent., and 13-43 per cent, of peptone-like bodies were found to 

 be bitter, while in samples containing 8-44 per cent., 8-60 per cent., 8-69 per 

 cent., and 5-09 per cent, of these bodies no bitter taste could be noticed. 



As but very small amounts of peptone-like bodies are present in vacuum- 

 concentrated extract, and but little change in the composition of nitrogenous 

 bodies is found, it is probable that the prolonged action of heat on the nitro- 

 genous material in the presence of the normal flesh acids and salts, the 

 amount of which increase as the evaporation proceeds, is the cause of the 

 marked change in composition found in the open-pan-concentrated extract. 

 The so-called "burned" flavour sometimes found in meat-extracts is 

 doubtless due to the same cause, for in vacuum-concentrated extract no 

 such undesirable flavour is noted. 



For permission to publish these results the author desires to express his 

 thanks to the Christchurch Meat Company (Limited), in whose chemical labora- 

 tory most of the work in connection with this investigation was carried out. 



