I LYCOPENE 119 



NHaOH 



CH3 CH3 CH3 CH3 



HON=CH- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CHCH=C- CH=CH- CH=NOH 



Bixindialdehyde dioxime 



Dehydration 



CH3 CH3 CH3 CH3 



I I I I 



NC- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CHCH=C- CH=CH- CN 



Hydrolysis 



CH3 CH3 CH3 CH3 



I I I I 



HOOC- CH=CH- C=CHCH=CH- C=CHCH=CHCH=C- CH=CHCH=C- CH=CH- COOH 



Norbixin 



The observation of Strain^i, ^j^^^ ^j^g ozonisation of lycopene also gives 

 rise to levulinic aldehyde and levulinic acid, is also in accord with the formula 

 given above. 



CHo CHo 



Numerous early investigations deal with the formation of carotenoids in the 

 plant during the ripening process. Thus Duggar^^ showed in 1913 that the red 

 tomato pigment is no longer formed at temperatures above 30°, a yellow pigment, 

 probably a flavone or fiavanol, being produced instead. The agents responsible for 

 the formation of lycopene are not, however, destroyed at 30° since yellow tomatoes 

 ripened at 30° again acquire a red colour due to lycopene on being restored to a 

 lower temperature. Some authors consider light to be a necessary agent for the 

 ripening process^^ ; according to Duggar, however, the ripening process is indepen- 

 dent of light but requires the presence of oxygen. The investigations of Duggar 

 were repeated and confirmed by Karrer and co-workers^*. 



KuHN and Grundmann^s, in 1932, examined the tomato pigment at different 

 stages of ripening by means of adsorption analysis. They obtained the following 

 figures for fresh fruit grown in the open. 



References p. 165-iyo. 



