132 Journal of Agricultural Research vol. xx. No. » 



CHARACTER OF FIXED OIL, AND CERTAIN OF ITS CONSTITUENTS 



It has been reported that the seed of Chinese colza is used in China for 

 its fixed oil, and such use has also recently been made of the seed im- 

 ported into this country. A study of the fixed oil showed that it was 

 present in very large amounts, up to 50 per cent or more, and that its 

 composition was similar to that of rape oils. It was a light yellow oil 

 and apparently was of an excellent quality. The oil expressed from the 

 seeds showed the characteristics given in Table V. 



Table V. — Characteristics of fixed Chinese colza oil l 



Density, 25 C 



Iodin No. (Hanus) 



Saponification No 



Percentage of insoluble acids and unsaponifiable matter 



Percentage of soluble acids 



Neutralization value of insoluble acids 



Mean molecular weight of insoluble acids 



Refractive index, 25 C 



Iodin No. insoluble acids 



Percentage of solid acids 



Percentage of liquid acids 



Iodin No. solid acids 



0. 9097 

 100.3 

 173-8 



96. 1 



.07 

 172. 6 



325-0 



1. 4695 

 104. o 



19-52 

 75.82 

 55-2i 



'Analysis by L. B. Burnett, formerly of the Oil, Fat, and Wax Laboratory, Bureau of Chemistry 

 United States Department of Agriculture. 



CHEMICAL CONCLUSIONS 



i. The volatile oil yielded by Chinese colza has been identified as cro- 

 tonyl isothiocyanate, an oil formerly found in rape. Crotonyl isothio- 

 cyanate is slightly lighter and allyl isothiocyanate slightly heavier than 

 water. The boiling points of the oils and other physical constants re- 

 ferred to in Table II permit ready differentiation. 



2. The yield of volatile oil varied from about 0.4 to 0.6 per cent, while 

 true mustards, with the exception of Sinapis alba, yielded from about 

 0.7 per cent up to more than 1 per cent of volatile oil of different com- 

 position. 



3. The fixed or fatty oil expressed from the seed showed the general 

 characteristics of rape oils, these being slightly different from the fixed 

 mustard oils. The iodin value, for instance, was about 100 or below 

 in case of rape oils and the Chinese colza oil, while it was above 100 in 

 the case of oil expressed from different mustard species. These oils 

 were obtained under similar conditions and were unrefined. Methods of 

 refining may change the iodin value. 



4. The yield of fixed oil varied from about 40 to 50 per cent, whereas 

 the true mustards examined usually contained less and rarely, if ever, 

 more than 40 per cent of a fixed oil. 



