264 Proceedings of Indiana Academy of Science. 



due to popping corn is tliat whicli tlie starcli undergoes forming soluble 

 stai-ch and dextrin. This is shown by the increase in blue color given by 

 the iodine test for starch as well as by the increased solubility of starch 

 and dextrin when extracted by cold water. 



It was found also that there is considerable increase in the amount of fat 

 extractable with ether after the corn is popped. This is probably due to the 

 thorough disruption of the cellular structure making more complete ex- 

 traction possible. It was noted too that there is a slight increase in the tiber 

 content when corn is popped. The action of malt diastase on the popped 

 corn shows that over half of the starch has been converted to a form capable 

 of reducing Fehling's solution. 



It is well known that a large amount of steam escapes when corn is 

 popped but it is usually considered that this comes only from the moisture 

 contained in the corn. This does not seem to be entirely the case. Since 

 the loss in weight on popping is slightly greater than that of the moisture 

 in the corn, and since there is no carbon dioxide gas produt-ed. the exces- 

 water may come from a partial breaking down of the starch molecule to a 

 less complex structure through the loss of water of constitution as shown 

 in the table which follows : 



Table 3 Showing the Loss of Water of Constitution in Popped Corn 

 Percent Percent Percent of 



The change taking place seems to be one of hydrolysis due to the action 

 of steam under a considerable pressure. The cellular starch wall is very 

 elastic permitting of wide distention, and loss of some cell granules, without 

 breaking. Other corn grains split open without much cell elasticity being 

 shown. 



Summary. 



I. The amount of moisture is not the determining factor in popping of 

 corn except in cases of extremes wet or dry samples. 



II. The time consumed in popping corn is an important factor; when 

 heating has been too rapid the corn does not have a chance to become 

 dextrinized throughout the grain, when heating is too slow the moisture 

 content becomes too low to explode the grain. 



III. Photomicrographs of popped corn show the cells to be greatly 

 enlarged and a considerable part of them disrupted releasing some starch 

 .granules which may be stained blue with iodine solution. 



IV. Popping corn increases the ether soluble fat, also the soluble starch 

 and dextrin and deci'eases the starch while the fiber is slightly increased. 



V. The popping of pop com seems to be caused by the multiple cell ex- 

 plosion of steam derived from water of constitution and from hygroscopic 

 moisture. 



