METHODS OF ISOLATION OF CAROTINOIDS 215 



tinoid from blood scrum by ether was a criterion of its xanthophyll 

 character. The instances of carotin extraction from human blood 

 serum which the writer has already mentioned show, however, that 

 this is not a safe basis for judging the character of the pigment 

 present. 



Isolation of Lycopin 



Several investigators have described the isolation of lycopin, which 

 is the characteristic red pigment of tomatoes, red peppers, the pulp 

 of the watermelon and a number of tropical fruits. The method to 

 be described here, however, is that used by Willstiitter and Escher 

 (1910), who first showed that this pigment is a true isomer of carotin. 

 These investigators first attempted to use the fresh fruits as the 

 source of pigment, but when they found that 135 kgs. of tomatoes 

 yielded only 2.6 kgs. of dry matter from which only 2.7 grams of 

 crystalline lycopin could be obtained, they decided on a canned 

 preparation of concentrated tomato soup of Italian make as better 

 suited for their work. 



Starting with 74 kgs. of the condensed tomato puree, it was first 

 dried in 8 kg. portions by shaking with 4 liters of 96 per cent alco- 

 hol, collecting the coagulum and repeating the operation with two 

 or three liters more of the alcohol. The coagulum was now pressed 

 as dry as possible and finally dried completely on the steam bath 

 before grinding to a powder. The total yield of dry powder was 5.6 

 kgs. This was completely extracted with carbon disulfide in a con- 

 tinuous extractor and the extract evaporated to dryness using dimin- 

 ished pressure as far as possible, and finally at a temperature of 40 C. 

 in a water bath. The residue was now treated with 3 volumes of 

 absolute alcohol, transferred to a suction filter and washed with petro- 

 leum ether. The yield of crude pigment amounted to 11 grams. The 

 purification of the pigment was accomplished in much the same man- 

 ner as carotin is purified. 



Isolation of Fucoxanthin 



The characteristic algse pigment, fucoxanthin, whose chemical rela- 

 tion to the carotinoids was discovered by Willstiitter and Page (1914) 

 was isolated in quantity by them in the following manner. Fifteen to 

 20 kgs. of the fresh algae (Phaeophycea) were extracted with 40 per 

 cent acetone, using 2 liters for each kg. of algao. This extract was 



