SECTION IX 

 STARCHES, GLANDS, HAIRS, &c. 



STARCH 



(Amylum) 



Source, &C. The official varieties of starch (Amylum, B.P.) are 

 those obtained from wheat, Triticum satlvum, Lamarck, from maize, 

 Zea Mays, Linne, and from rice, Oryza satwa, Linne (N.O. Graminece). 

 Wheat is largely cultivated in temperate climates, whilst maize and 

 rice are grown chiefly in warmer or subtropical countries. 



In preparing the starch from the fruits, it is essential in the first 

 place that the cells containing it should be ruptured in order to liberate 

 the starch grams, and in the second place that the starch grains thus 

 liberated should be separated from other matters, both soluble and 

 insoluble, that accompany them, especially from the nitrogenous gluten 

 which often clings to them pertinaciously. The cells are ruptured 

 by grinding the softened grain to a pulp, and the gluten is removed 

 by one of the following processes, viz. : 



(a) A mixture of crushed gram and water is allowed to undergo 



putrefactive decomposition ; the gluten is decomposed, 

 lactic, acetic, and other acids being produced and re- 

 moved by washing. 



(b) The crushed grain is mixed with a dilute solution of caustic 



soda by which the gluten is dissolved. 



(c) The grain is crushed and mixed with water to a dough from 



which the starch grains are washed by kneading it in 

 a stream of water, leaving a mass of gluten behind. 



The starch is purified by washing, straining and allowing the milky 

 liquid containing starch grains in suspension to clear, by which a more 

 or less complete separation into pure starch and starch mixed with 

 varying amounts of cell-debris is effected. It is finally dried, during 

 which the moist mass gradually splits up into angular fragments. 

 These are then ground to form starch powder. 



