When making microwave popcorn I have always felt frustrated to reach in and find a handful of unpopped kernels at the bottom of the bag. I have never understood why these select kernels did not pop while others did. Looking for a solution to pop all my kernels, I learned the art of how microwave popcorn pops.
On every website that google search has led me to, each one tells me: popcorn is a special kind of corn. What makes this kind of corn special? The most obvious difference between popcorn and other corn is that is pops. Other than its “pop-ability” , popcorn kernel contains a drop of oil and water mixed with a starch. This drop, contained by the endosperm, is surrounded by a hard outer coating, or the pericarp. When the oil and water inside are heated, it turns into steam. Pressure from the expanding steam builds inside of the kernel. At approximately 180 °C, the popcorn kernel has reached its maximum amount of pressure and the kernel pop. When popcorn pops, the outer shell of the kernel is basically turning inside-out.
Now that I know the science of how a popcorn kernel pops, I am curious to know why some of the popcorn kernels do not pop. Bruce Hamaker of Purdue University hypothesizes that the answer to all unpopped kernels is in the chemistry of popcorn. In his study, Hamaker looked at 14 genetic varieties of yellow popcorn. He analyzed how they popped and counted the number of unpopped kernels from 4% to 47%. The popcorn kernels that had little leftover kernels were discovered to have a stronger outer shell.
A popcorn kernel’s shell is made up of cellulose. The stronger kernels were found to have a more ordered crystalline arrangement of cellulose molecules. If the shell of the kernel is strong, then the pressure will be held in longer, maximizing moisture retention. This causes a complete pop for more kernels. A weak popcorn shell can permit the oil and water inside the kernel to evaporate into the bag, which means that the pressure built up in the kernel may not be strong enough to cause a pop.
So how can I guarantee that all the shells of my popcorn kernels are strong and pop-ready? The answer is chemical modification. Researchers are working on creating a popcorn with the stronger crystalline cellulose structure. The genetically modified popcorn will possess the same process of popping, it will just have a different chemical makeup. There is even a new corn plant being genetically engineered to produce this kind of popcorn with a strong shell.
As an avid popcorn consumer I am reassured to know that someone shares the same unpopped kernel struggle as me. Thankfully they felt so strongly that they have set out to find a solution. I am happy to know that one day, maybe in the next 3 to 5 years, I will be able to fully enjoy the entire bag of kernels as a popped salty snack and no kernel will go unpopped.
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