With butter, natural, cheese, or sweet, popcorn is one of favorite snacks. But why do they explode to the point of becoming crunchy? In fact, they have prompted various studies ranging from the chemistry of their components to the social and cultural aspects of their existence, but let’s delve deeper into their science.
According to the study ‘Popcorn: critical temperature, jump and sound,’ the characteristic sound of popcorn is the result of the release of water vapor, not the noise of the shell breaking. The inside of the corn kernel acts as a sound amplifier, making the pop audible to humans.
What makes popcorn explode?
According to science, corn is composed of starch and proteins inside, covered by a thin layer called the pericarp. When we heat the grain, we attempt to evaporate the water within it. When the interior temperature of the corn reaches the boiling point, the corn’s proteins and starches soften, and the contained moisture turns into steam.
The pressure inside the corn kernel, which is seven times greater than the outside pressure, allows the starches and proteins of the grain to expand, leaving a crispy and light surface. The starch inside melts and comes out under pressure, causing it to burst when it cools upon contact with the air, forming the fluffy flakes we know as popcorn. This process starts at a temperature of 177 degrees Celsius.
What gives popcorn its characteristic aroma?
Freshly made popcorn emits a very distinctive aroma. We can all quickly identify this smell. The most significant compounds in the smell of popcorn are:
- 2-acetyl-1-pyrroline: The toasted smell of popcorn, similar to the smell of hot, buttered popcorn. Interestingly, this compound is also responsible for the aroma and flavor of white bread or basmati rice.
- (E,E)-2,4-decadienal: The greasy or fried smell of popcorn. It is a substance found in butter, meats, fish, etc. The concentration of this substance in foods influences its smell, sometimes resembling citrus in certain cases.