What Puts “Pop” in Pop Corn. 263 
the volume of the popped corn shown in Photograph I below. When 
popped in lard it was found that popping started at 340° F and _ pro- 
ceeded rapidly when a temperature of 380° F had been reached. If less 
time than 3 minutes was consumed in popping the volume would be lessened 
because many kernels would be only partly popped while if a greater time 
was used the corn would be dried out too much and good popping made 
impossible. 
Effect of Moisture on Popping. 
An attempt was made to subject a series of samples of the same corn to 
extremes of moisture and dryness and then test their ability to pop. The 
results of these tests are given in the table below. 
Table 2 Showing the Relation o, the Moisture to Popping of Corn 
Sample Percent Percent 
Duplicate Moisture Pop 
1 iti) sat 93 .0 
2 16.23 87.0 
3 18.92 85.0 
4 24.3 84.0 
5 Pale ch 60.5 
6 20.84 25.0 
7 A 4.0 
It will be noted from Table 2 that the moisture content is not a prime 
factor in popping of corn except when extreme limits are reached. 
There is a difference in the appearance after it is popped and the way of 
popping between high and low moisture corns. The former gives a muffled 
sound when popping whereas the latter pops with a loud sharp report and 
emits very little fragrance compared to the former. The photographs 2 and 
3 will serve to show the moisture effect on popping and the appearance of the 
popped grains. 
Effect of High and Low Protein on Popping. 
It was surmised that the great differences noted in popping might be due 
somewhat to the horny protein layer surrounding the starch in some 
samples, hence the protein contents of the samples were obtained, but this 
clue was found false as shown in Graph I, in which the protein, moisture 
and percent of pop are graphically illustrated and no relation seems to be 
apparent between the percent of popping and the protein content. 
Microscopical and Chemical Studies. 
In order to study the changes going on within the cells it was thought 
worth while to make some photomicrographs of a cross section of the pop 
corn grains both before and after being popped. ‘These differences are 
shown in photomicrograph 1, 2, 3 and 4. It will be noticed that the cell 
walls and the contents of the cells are very greatly expanded and more 
clearly defined in the popped corn than in the unpopped indicating exten- 
Sive molecular rearrangement in the cellular structure. 
The chemical analysis seems to indicate that the most pronounced change 
