264 Proceedings of Indiana Academy of Science. 
due to popping corn is that which the starch undergoes forming soluble 
starch 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. 5 
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 fiber 
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 produced, the excess 
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 
Pereent Pereent Percent of 
Sample No. Moisture Loss on Water of 
Popping Constitution 
A 7.96 8.68 0.72 
B 10-21 ay rfl 1.50 
© 8.56 9.60 1.04 
D 14.31 15.50 1.19 
E 14.04 14.50 0.46 
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. 
Ill. 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 decreases the starch while the fiber is slightly increased. 
VY. The popping of pop corn seems to be caused by the multiple cell ex- 
plosion of steam derived from water of constitution and from hygroscopic 
moisture. 
