28 CAROTINOIDS AND RELATED PIGMENTS 



the structure of carotin using 150 grams of the pigment isolated from 

 carrot meal by extraction with petroleum ether. His efforts led only 

 to the production of amorphous products, all of high molecular weight. 

 The constitution of the pigment thus remains to be determined. 



Euler and Nordcnson (1908) also isolated carotin from carrots in 

 quantity sufficient for analysis. Their results confirm the Willstiitter 

 formula. The purified crystals from 25 kilos of fresh carrots were 

 found to contain xanthophyll, which was identified by the color of 

 the crystals and their solubility properties. Palmer and Eckles 

 (1914g) have also shown the presence of xanthophyll carotinoids in 

 the carrot root by the Tswett (1906c) chromatographic method of 

 analysis, but van Wisselingh (1915), using microchemical crystalliza- 

 tion methods, did not observe any. xanthophyll crystals. 



It appears that anthocyanins, also, may accompany carotinoids in 

 the carrot root. Wittmack (1904) has described a red variety of 

 carrots (Daitcus carota, var. Boissieri Schweinfurth) which contains 

 both carotinoids and anthocyanin. 



Many other investigators have isolated carotin crystals from car- 

 rots without, however, submitting them to chemical examination. 

 According to Schimper (1885) and Courchet (1888) carotin exists in 

 the carrot tissue in crystalline form. Van Wisselingh (1915), how- 

 ever, has shown that the little tubules which Schimper and Courchet 

 observed are not true crystalline forms. The author, also, has never 

 observed any but granular deposits of carotin in sections of the fresh 

 carrot tissue. 



Carotinoids in Other Roots 



Very few other roots have been examined for carotinoids although 

 several which are widely used as food are characterized by their 

 yellow color, e.g., the yellow parsnip root (Pastinaca sativa), and the 

 sweet potato (Ipomoea batatas) , especially the highly colored varieties 

 grown in the southern part of the United States, popularly called 

 Yams. The pigments of these' roots should be examined. 



Formanek (1900) has studied the pigment of the red beet (Beta 

 vulgaris) , and believes that the red pigment changes into a yellow one 

 under certain conditions. The absorption bands of the latter are iden- 

 tical in -position with those of carotin. Formanek's red pigment 

 showed only one absorption band in the yellow part of the spectrum 

 and is undoubtedly an anthocyanin. Its apparent transformation into 

 carotin cannot at present be explained. 



