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Why does popped popcorn have less calories?

  1. Jan 17, 2006 #1
    Somebody told me this, giving some stupid explaination of popped popcorn being mostly "air." I didn't believe them because the mass and chemical composition will still be the same, but I just checked a bag of popcorn and it has 10 fewer calories from fat when it's popped than when it's unpopped. Huh? I know their explanation is obviously wrong, but why physically or chemically would popped popcorn have less calories?
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  3. Jan 17, 2006 #2


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    Must be that the steam that pops away carries some fat with it. Or else the manufacturer doesn't have to count the fat that is typically left inside the bag after it is emptied according to their popping instructions.
  4. Jan 17, 2006 #3


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    I know when the corn explodes, hot oil goes everywhere.
  5. Jan 17, 2006 #4


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    That's the one. A lot of foods have data for the uncooked (all meats, for example) or total package on the label and specify what conditions the data is relevant for. With popcorn, it just happens that a lot of the butter stays in the bag.
  6. Jan 18, 2006 #5


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    Oh, you guys are talking about microwave popcorn! I was puzzled, because I pop popcorn the old-fashioned way, which involves adding some oil or butter, not losing it.
  7. Jan 18, 2006 #6


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    Yeah, I was puzzled on that too.. I thought you were referring to the corn (not packaged versus unpackaged)

    At Purdue Univ, for example, they pop all experimental popcorn crosses using an air popper. Using the same volume of corn, each cross will vary in characteristics, e.g. total expansion, texture, percent popped (for a valid comparison you need to use the same volume of dry corn and same moisture content). But I go along with Mindscrape original conception, oil content before and after remains constant .

    For the lucky life science students we got all the free popcorn we could eat, Yummm :tongue2:
    Last edited: Jan 18, 2006
  8. Jan 19, 2006 #7
    What about volume?

    Wouldn't the volume have something to do with it? For instance, on most popcorn, the nutrition values are shown in values for popped and unpopped, as stated before, but the amount for unpopped is 3 tbs (for example) and the amount for popped is 1 cup. 1 cup of popped popcorn is WAY less than 3 tbs of kernels. In other words, 3 tbs of kernals will probably make a few cups popped, because of how large the popped kernals are compared to the unpopped. Try it out, and measure the popped.

    What I don't understand is that they list it in the nutrition guide under the same amount of servings which is WAY off. Not sure why they do that, unless I'm way off on the whole idea to begin with.

    It's too bad, I was thinking my big bag of buttery popcorn was only 30 calories...(with hardly any fat)...lol...wishful thinking.
  9. Jan 26, 2009 #8
    I'm not a science expert by any means, but could it have to do with the amount of energy (calories) expended by the corn kernel as it pops? If it uses some of its energy to pop, it would make sense that there is less calories in the popped version of the kernel. Anyone smarter than me on this, please let me know if this makes sense or not.
  10. Jan 26, 2009 #9

    jim mcnamara

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    No. The corn itself has the same caloric content. popped or dried. Good grief, Charlie Brown.

    According to the USDA Nutrient database:
    100g of dried white corn has 386 kcal
    100g of white popcorn air popped - no oil - has 387 kcal

    The 1 kcal is probably due to different varieties tested - corn has varying oil content in the seed.

    The caloric content of Orville Redenbacher's popcorn as it actually goes down the hatch is anybody's guess - depends on the oil & butter & additivies left behind in the bag.
  11. Jan 26, 2009 #10
    Are you sure jim mcnamara?The database has not provided any experimental uncertainties and there may be a slight difference.Popping the corn results in a physical change and possibly biochemical changes as well. I think Shelbie 3 makes an interesting point and it could be that popping requires some internal energy from the corn itself as well as energy from the external source.
  12. Jan 26, 2009 #11

    Andy Resnick

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    This is microwave popcorn? The calorie content before and after popping must be unchanged, unless as others point out, some of the oil/fat is left behind in the bag. 10 calories of fat is 1 gram, about 1/5 teaspoon (not much).
  13. Jan 26, 2009 #12

    Andy Resnick

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    The popping comes from water in the kernel. Water has no caloric value (as food). Now, if you burned the popcorn into a cindery agglomerate, the calorie value would be greatly diminished.
  14. Jan 27, 2009 #13
    I think the whole process might be much more complicated than is currently understood and that it might make an interesting research project.I cannot think of any practical applications that may may result from such research.Are there any other grains or seeds or biological structures which pop when heated?
  15. Jan 27, 2009 #14
    the mess that Reddenbacher leaves in my microwave could easily account for 10 calories. it's at least a gram of fat!
  16. Feb 27, 2009 #15

    The hard outer shell of the corn kernel holds moisture in as it vaporizes and expands. At the same time, the starch in the kernel is gelatinized. (It melts and loses its crystalline structure, and to some extent as far as I understand it, may be broken down into smaller molecules.) When the pressure inside the kernel reaches a level the seed coat cannot hold in, it ruptures. Then as the starch expands it cools, forming the familiar popped kernel. The steam process is a physical change, not chemical. The procession from solid to liquid to vapor does not change the chemical structure of the substance being heated.

    Gelatinization may be a chemical change that occurs in starch as a result of being heated or it may just be a physical change. I do not know whether it changes the nutritional profile of the grain to a significant degree. I will ask my chemistry/nutrition professor.

    And yes, you can pop other grains. Popped quinoa is fun and nutritious.

    Here's a video of a kernel popping in slow motion :-)

  17. Feb 28, 2009 #16
    I would think that a manufacturer of packaged microwave popcorn knows exactly how much hydrogenated oil (Crisco) it adds to each package and has to put that down as the ingredients. Since it has a vested interest in making people think there is as little fat in there as possible (without mentioning that it is putting heart stopping, artery clogging shortening in there instead of plain old oil) it is also saying how much is in the actual consumed product. Plenty is indeed left in the package since the coating power of hydrogenated oil doesn't just apply to arteries and oil does evaporate under heat. I would guess that they get the popcorn out of the package as quickly as possible to measure the actual amount of fat in the finished product, unlike the consumer who eats it in the package and is actually consuming a little more than what they are saying is there.
  18. Mar 2, 2009 #17
    Could it be that heating burns some of the calories off ?
  19. Mar 2, 2009 #18


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    Finding out that Perdue has a popcorn lab made this thread worth it.
  20. Jul 16, 2010 #19
    I contacted Con Agra foods with this question, and here is their reply:

    Thank you for your email concerning our Orville Redenbacher's® Microwave Popcorn, a product of ConAgra Foods.

    We apologize for the confusion regarding our labeling. We do not recommend comparing the unpopped and popped nutritionals.

    The FDA requires nutrition values for unpopped popcorn be on the label. The difference in the nutritionals between the un-popped kernels and the popped product is the fact that some of the fat and salt sticks to the bag. The un-popped nutritionals include everything they put in the bag and the popped nutritionals include only what the consumer will be consuming.

    We appreciate your patronage and value our consumers. We hope you will continue to enjoy our line of quality food.

    I recommended that they add the above explanation on their labeling.
  21. Jul 16, 2010 #20


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    Ah, you want an explanation on the box. I guess I read the explanation years ago as I've always known that not everything adheres to the popcorn and not all kernels pop. Or maybe it was common sense from looking at what was left in the bag.
    Last edited: Jul 16, 2010
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