Popcorn polyphenol power

Popcorn does not exactly have a reputation as a health food. This is largely because of the way it has been prepared at carnivals and movie cinemas around the world. A report in 1994 from the Centre for Science in the Public Interest claimed that, “A medium-size buttered popcorn contains more fat than a breakfast of bacon and eggs, a Big Mac and fries, and a steak dinner combined.” This is not a ringing endorsement but now a study has said that popcorn may not be so bad after all. To understand how this can be true we need to remind ourselves what popcorn is.

Popcorn is made from the kernels of the maize (corn) plant. Each kernel of popcorn contains a certain amount of moisture and oil. Unlike most other grains, the outer hull of the popcorn kernel is both strong and impervious to moisture. The starch inside the corn kernel consists almost entirely of a hard, dense type. As the oil and the water used to cook the kernels are heated past the boiling point, they turn the moisture in the kernel, which has a moisture-proof hull, into a superheated pressurized steam. Under these conditions, the starch inside the kernel softens and becomes pliable. The pressure continues to increase until the breaking point of the hull is reached: a pressure of about 135 psi (930 kPa) and a temperature of 180 °C (356 °F). The hull ruptures rapidly, causing a sudden drop in pressure inside the kernel and a corresponding rapid expansion of the steam, which expands the starch and proteins of the endosperm into airy foam. As the foam rapidly cools, the starch and protein set into the familiar crispy, puffy popcorn.

Special varieties of corn are grown to give improved popping yield. Some wild types will pop, but the cultivated strain for popping is Zea mays averta.

Essentially then, popcorn is a wholegrain food and it is only when you start adding butter, salt, and sometimes sugar and goodness knows what, that it becomes a problem food. Theoretically, a whole grain food should contain some goodness and that is what researchers from the University of Scranton set out to test.

They found that in fact the hulls of the popcorn kernel are a rich source of antioxidant polyphenols. They found that one serve (ten grams) of corn kernels will provide about 300mg of polyphenols. Compare this to a serve of fruit (150 grams) which, depending on the fruit, will yield around 160mg of polyphenols. Of course, ten grams of corn kernels translates into a lot of popped corn and fruit has other nutrients that corn lacks.

In terms of preparation, air popping is the way to go, and of course once you add fats into the cooking or serving then your calories increase and the benefits go. Microwaved popcorn has twice as many calories as air-popped corn as does corn popped in oil.

In all, simple corn popped in heat like the Aztecs used to do it is not such a bad thing. Good luck finding that at your local movie theatre though and smuggling in your own “pure pop” might be frowned upon. It might be revolutionary, but you could try just watching the movie? Or is that just too way out there?

Terry Robson

Terry Robson

Terry Robson is the Editor-in-Chief of WellBeing and the Editor of EatWell.

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