WHAT PUTS “POP” IN POP CORN? 
R. H. Carr and E. F. Rretey, Purdue University. 
4 7) 
“What puts the ‘pop’ in pop corn?” is a question which is often joked 
about and one which seems never to have been considered seriously enough 
to lead to any investigation. Some think the subject is.,not worth study 
while others look upon it as one of the mysteries of nature which can never 
be unfolded and to them it is in the same class as the question, “Why is 
the grass green”? Pop corn has been a very popular food from very early 
times and is becoming more common as improved methods of preparation 
render it more and more appetizing. 
Theories of Popping. 
The writer formerly was led to think the cause and degree of popping was 
in proportion to the hygroscopic water contained in the corn when heated, 
but a little investigation convinces one that popping is quite independent of 
the water content except between very wide limits, besides other kinds of 
corn such as dent or sweet do not pop wide open at any moisture content. 
Some have thought the action to be similar to that of Professor Anderson’s 
puffed corn or wheat, etc., in which the outer covering holds tenaciously 
enough to expand without breaking. This, however, is not the case with pop- 
corn as it is possible to drill holes in the grain or slit the sides of the hull 
with a sharp knife and still have the grain pop wide open on being heated 
in a proper way. 
Scope of Investigation. 
The study of this subject is still going on but the points investigated so 
far concern mainly the mositure and protein contents, percent of popping, 
time of heating for best popping, microscopical appearance of popped and 
unpopped corn and changes in composition after popping. 
The 50 corn samples tested were secured from various sources. Many 
were from the farmers who grew the corn, some were obtained in grocery 
stores in different Indiana towns. They were mostly of the rice corn 
variety. Some of the samples are known as Australian Hulless, and some 
as California Golden. The percent of moisture, pop and protein content of 
the samples are given in the table which follows: 
