food of maw studies. 22x) 



Effects of Popping upon the Chemical Composition 

 of Indian Corn. 



The physical effects of heat upon the dried kernels of certain 

 varieties of Indian corn is well known. Not only does the corn 

 acquire a marked flavor, agreeable to the average palate, but the 

 kernels expand enormously, while the texture is radically 

 changed so that it is easily masticated. Some varieties of corn 

 when thus heated swell quietly without bursting the outer cover- 

 ing; others, like the sweet corn, expand explosively, but without 

 breaking the outer skin ; still others suddenly burst open with 

 sharp detonations, exposing the clear white of the starchy 

 endosperm. The latter varieties have thus received the dis- 

 tinctive name of "pop-corns." 



The expansive force which results in popping was formerly 

 believed to be due to the vaporization of the volatile oils present. 

 Storer,* however, states that corn from which the oils had been 

 extracted with ether continued to pop well. Brewer, t Wilbert,t 

 Sturtevant ** and others, attribute the popping to the rupture 

 of the individual starch grains, due to the formation of steam. 

 In proof of this statement mention is made of the fact that 

 even the best varieties, if too old or too dry, will not pop unless 

 the grains are previously soaked and then dried for 4 to 12 hours, 

 when the popping qualities are regained.*** The effects are 

 most marked in those varieties of corn in which there is a large 

 amount of the dense corneous endosperm. 



The chemical changes, although less manifest, are of interest. 

 Experiments made at this Station and recorded below indicate 

 that the physical changes are more important than the chemical. 

 Three varieties were examined : 



No. 6934. Popcorn. Purchased in Orono. 



No. 6936. Yellow Canada corn. From Bangor seedsman. 



No. 6938. White Corey sweet corn. Purchased in 

 Bangor. 



The popping was done over a coal furnace fire in an ordinary 

 wire popper. While it was thoroughly done, great care was 

 taken to avoid scorching. The analyses of these corns, before 

 and after popping, are given in the table on the following page. 



* Stover, D. A. Bui. Bussey Inst., 3 (1904), pp. 77-79. 

 t Brewer, Wm. A. Tenth Census United States, Vol. 3, p. 103. 

 t Wilbert, M. I. Amer. Jour. Phar. 75 (1903), No. 2, pp. 77-79. 

 ** Sturtevant, E. Lewis, Bui. Torrey Bot. Club, 21 (1894), p. 522. 

 *** Kraemer, Henry. Science, 17 (1903), pp. 683-694. 



