Tuesday, February 10, 2009

Goodness gracious great balls of popcorn!

Popcorn may be the most amazing snack in existence today. Not only is it small, white and fluffy, it’s also pretty high in fiber and low in calories… and it tastes great covered in salt. I’ve always had a few questions about this crazy awesome snack, but never made the time to look any of it up…
Anyway, I finally did that and thought it’d be fun to share what I found…

The physics and chemistry behind how popcorn ‘works’ is almost as enjoyable as it’s puffy texture. The actual origin of popcorn dates back to the time of the Native Americans long before European settlers ever arrived. The oldest popcorn ever to be discovered was found in the “Bat Cave”, located in central New Mexico and is believed to be around 5600 years old.
Popcorn has a hard ‘outer shell’ (called the pericarp) which traps moisture inside the kernal (the seed of the corn plant). Inside this hard outer pericarp is a tiny corn embryo surrounded by some starchy material and water.

When you heat popcorn by using a microwave, hot air or oil, you are essentially heating the water inside until it boils. This boiling water produces steam and a pressure inside the kernal which, when it gets hot enough, causes the popcorn kernal to explode violently and turn itself almost completely inside out.

The ‘white stuff’ you see of the popcorn is the starchy material that the embryo of the plant would have used for energy to grow had this little guy not exploded in your microwave.

A recent study by Hamaker et. al (2005) was designed to determine how pericarps with different internal structures might lead to bigger, fluffier popcorn with a smaller percentage of unpopped kernels. It is known that the pericarp is mostly made up of two different compounds, cellulose and arabinoxylan.

This study essentially found that, while the pericarps of the many different varieties of popcorn tested have essentially the same amounts and ratios of both compounds, the manner in which these chemicals interact during heating varies from strain to strain. In the better popping kernels, these compounds would organize themselves into stronger crystal-like walls around the rest of the seed which would help contain the moisture until the pressure became too great from heating and the kernel exploded. In kernels with less than desirable popping performance, these compounds would not organize so tightly and leave 'holes' in the pericarp wall. These 'holes' allow the boiling water inside the kernel to simply escape to the outside air allowing no pressure to build up inside the seed and no delightful explosion to take place.

1 comment:

  1. I remember doing an experiment on popcorn when I was in third or fourth grade. We popped some kernels which appeared to be normal and then we proceeded to poke a hole in the kernel with a pin. When the covering had a hole in it, it did not pop. I knew it was because the pressure could not build up inside the kernel, but at that age, that's pretty much all the information you can handle.