CAPSICUM 



123 



characteristic, thickened margin ; they were originally attached to 

 the dissepiment, but are frequently found loose in the cavity. 



Capsicum fruits have a characteristic but not powerful odour, and 

 an extremely fiery pungent taste. The latter resides principally in 

 the membranous dissepiment that divides the fruit into two cells. 



The student should observe 



(a) The shape and size of fruit and peduncle, 



(b) The dissepiment and its pungent taste, 



(c) The shape of the seeds. 



Constituents. The most important constituent of capsicum fruit 

 is the pungent principle, capsaicin (0'02 per cent.), first isolated 

 by Thresh (1876) in colourless, odourless crystals. It also contains 



FIG. 68. A, Zanzibar ; B, Sierra Leone ; c, Japanese 

 chillies ; D, Bombay . capsicums. Natural size. 

 (Chemist and Druggist.) 



a minute quantity of a liquid alkaloid which is not pungent, a 

 fixed oil, and red colouring matter ; the seeds may contain traces 

 of starch. 



Capsicum fruits yield about 5 (not over 7) per cent, of ash and from 

 20 to 25 per cent, of alcoholic extract, known in commerce as capsicin ; 

 the same name has also been applied to an ethereal extract as well as 

 to a soft red substance extracted by ether from an alcoholic extract. 

 All of these contain capsaicin associated with fixed oil, colouring 

 matter, &c. 



Capsaicin (capsacutin) is secreted by the epidermis of the dissepiments of 

 the fruit, between the outer cell wall and the cuticle. 



Thresh assigned to it the formula C 9 H 18 2 , which has been corrected to 

 C 18 H 27 NO 3 . The crystals melt at 65 and at higher temperatures are volatile, 

 the vapour being extremely irritating ; they are phenolic in character, dissolving 

 in dilute solution of potassium hydroxide, but being reprecipitated by a current 

 of carbon dioxide. The pungency is not affected by the alkali but is destroyed 

 by oxidation with potassium bichromate or permanganate. Much interest is 



