8 



BULLETIN 632, U. S. DEPARTMENT OF AGRICULTTJBE. 



acids were present. These insoluble acids were separated into the 

 solid and liquid acids by means of the lead-ether method (17, p. 45). 

 The mixed acids were found to consist of solid acids 17.54 per cent 

 and liquid acids 75.84 per cent. 



The physical and chemical properties of the insoluble acids and the 

 solid and liquid acids, were determined with the results shown in 

 Table II. 



Table II. 



-Physical and chemical properties of insoluble, solid, and liquid acids 

 of tomato-seed oil. 



Physical and chemical 

 properties. 



Insoluble acids. 



Solid acids. 



Liquid acids. 



Color Pale golden yellow; 



partly solid. 



Odor Fatty, nutlike 



Taste Sweetish, fatty 



0.9100. 

 1. 4655. 



Specific gravity at 25° C J 

 Index of refraction at 

 25° C 



Congealing point | +21.5° C. to +20.5° C 



Neutralization value ' 180 



Iodin value 104.3 



Snowy white, flaky j Pale golden yellow. 



Fatty I Pleasant, nutlike. 



Fatty, tallowlike I Sweetish, nutlike, be- 

 coming slightly bitter. 

 0.9013. 



Melting point, 53.5° C. .. 

 204 



1.4654. 



192.3 

 130. 



The solid acids, comprising 17.54 per cent of the oil, probably 

 consist largely of palmitic and stearic acids with neutralization 

 values of 219.1 and 197.5, respectively. The neutralization value 

 204 would indicate a mixture of these two acids. Although the melt- 

 ing point of crude solid acids is considerably lower than either 

 palmitic or stearic acids, which melt when pure at 62° C. and 69° C, 

 respectively, it is very probable that this is due to the presence of 

 impurities. 



Calculating from the neutralization value 204, the mean molec- 

 ular weight of the solid acids was found to be 275. This indicates 

 the presence of palmitic and stearic acids, since the molecular weight 

 of these acids are 256 and 284, respectively. 



In order to ascertain the approximate proportions of these two 

 acids in the mixed solid acids, a calculation was made according 

 to the method suggested by Lewkowitsch (10, v. 1, p. 515), using as 

 a basis 275, the mean molecular weight of these solid acids. By 

 this method, the percentage of palmitic acid was found to be 67.8 

 and of stearic acid 32.2. 



Since 17.54 per cent of the original oil consists of solid acids, the 

 oil therefore contains palmitic acid 11.88 per cent and stearic acid 

 5.64 per cent. Because the palmitic and stearic acids exist in the oil 

 as palmitin and stearin, it is necessary to reduce the above figures 

 to terms of these glycerids. The glycerid palmitin contains 95.29 

 per cent of palmitic acid, and the glycerid stearin contains 95.73 

 per cent of stearic acid. J$y calculation, therefore, it is found that 



