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Where do the calories go when you pop corn?

  1. Apr 25, 2008 #1
    I was reading the back of a pop corn bag and noticed that corn has twice as many calories before you pop it.

    C = kc = 1000xcalories:

    The bag claims that there is 120C in 3 tablespoons of unpopped corn and 6 tablespoons total. That is 240C for the unpopped corn in the bag.

    The bag also claims that there is 7.5 cups of pop corn after popping it and there is 15C per cup. That is 112C.

    More than half the calories are missing (128,000 calories to be exact)!! I had someone tell me that mabey it goes into heat energy though all the heat energy should be coming from the microwaves.

    The steam that leaves the bag should only be H20 with no calories. This is a lot of calories to be missing and certainly way beyond the point of uncertainties in manufacture measurments.

    Does anyone know where the calories go?
  2. jcsd
  3. Apr 25, 2008 #2


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    This is just a wild idea but....what about the calories contained in the butter? I wonder if it's included in the "pre-pop" figure. I am thinking about this because of the amount of butter and salt that stays in the bag after we microwave popcorn. Could that explain the "missing calories mystery"? Only a fraction of the butter in the bag actually gets spread on the popcorn. So if they include the mass and calories of the butter put in the bag in the figure of 3 tbsp at 120 C per tbsp, and if the figure of 15C per cup of popcorn obtained was actually measured from popcorn coming out of the microwave, it would make sense that all the calories contained in the butter that remained in the bag would be lost.

    Just a crazy thought....
  4. Apr 25, 2008 #3
    Your bag could very well contain a misprint =)
    I think a popped kernel weighs less than an unpopped one, but also takes up more room. So depending on which they used as a measurement, they might've botched the calculation.
  5. Apr 25, 2008 #4


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    I would first suspect the measurement techniques.
    1] First, tablespoons of kernels and cups of popcorns (packing problems) are very inaccurate in determining how much actual food there is in each portion.
    2] You are then deriving (which has its own errors) how much there is in total of each.
  6. Apr 26, 2008 #5
    Popcorn does have fewer calories. The kernel contains oil as well as water.
  7. May 9, 2008 #6
    Water does not contain any calories, it is the product of spent calories right?

    We are talking about 535,552 joules of energy disapearing after popping the corn. It takes about 2 minutes to pop the corn in a 11kw Microwave, 535,552 joules is enough energy to power the microwave for almost half of that time. The pop corn can almost pop itself!!
    Last edited: May 9, 2008
  8. May 9, 2008 #7
    Water doesn't contain any calories, but oil does. I don't know how many calories the oil accounts for. A lot of the stuff dissolved in the water probably gets released when the kernel explodes also.
  9. May 15, 2008 #8
    Oil isn't dissolved in the water.... :tongue:

    But here's some food for thought. I believe that you maybe have seen a piece of meat in the fryingpan? It will contract and the proteins will coagulate, thus leaving you with a somewhat different state of meat, than raw meat that is. When you cook, heat, boil, electrocute or whatever thermodynamical device you use to process food. You will lose nutritional value of the food-stuffs.

    What happens (my theory) is that as previous authors have been foretelling, the oil leaves the corn. The water leaves the corn too. The oil in the corn would probably be around 2/3 or more of the total calories lost. The rest will probably be heat. (now I assume your way of describing the process is true).

    We could get increasingly technical and use PDE for heat-eq and stuff like that. Dissintegrateing matter and such. Obviously the only thing that happens is that entropy increases in the process and matter/energy/table spoons of corn will form another state of matter, one of less energy than the unprocessed corn.

    I hope this was helpful, if I am wrong, plz point that out so I may learn.
  10. May 15, 2008 #9
    I didn't say oil was dissolved in the water.
  11. May 16, 2008 #10
    That's true... my bad. :redface:
  12. May 16, 2008 #11


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    According to wikipedia ratio of carbohydrates to fat in maize is about 19:1.2 (w:w). Assuming that fat energy content is twice that of hydrocarbons, removing all fat will strip around 12% of the calories. Not 50%.

    I bet on misprint, miscalculation or misdetermination.

    Last edited by a moderator: Aug 13, 2013
  13. May 16, 2008 #12


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    I can't help but wonder why they put the calorie content of unpopped popcorn on the bag. Surely no one is going to eat it that way!
  14. May 16, 2008 #13
    Ok, I think it is about time for me to call the number on the back of the bag for questions. I have a feeling it isn't gonna be pretty though.
  15. May 16, 2008 #14
    How many angels dance on the head of a pin! Burn The un-popped and then the popped in a calorimeter and develop your own numbers!
  16. May 17, 2008 #15
    You never know, stranger things have actually happened :rofl:

    Borek: I checked your numbers and found something rather funny.

    Sweetcorn (seeds only)
    Nutritional value per 100 g (3.5 oz)
    Energy 90 kcal 360 kJ <.. look at this.

    Popcorn, air-popped, no additives
    Nutritional value per 100 g (3.5 oz)
    Energy 380 kcal 1600 kJ <.. look at this and compare.

    So after you popped the corn it is actually roughly four times as much calories in the popcorn as in sweetcorn. Although this gives me the conclusion that the seeds are prepared with some form of additive. Although the numbers for the popcorn are without additives, I believe that OP's popcorn has that.
    Last edited: May 17, 2008
  17. May 17, 2008 #16


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    The kid on the end of the phone is not gonna have a clue what you're talking about!!! Perhaps you should just put it down to a typo/incorrect info, and go and find something else to waste your time on!
  18. May 17, 2008 #17


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    Fearless - perhaps sweetcorn numbers are for the fresh (high water content) corn? Pop corn is made from dried out seeds, so there will be huge difference.

    Last edited by a moderator: Aug 13, 2013
  19. May 17, 2008 #18
    Borek: Yeah that is true, but a engineer takes the data as close he can to the real deal. I don't feel like stuffing a calorimeter with dried out maize. :smile:

    But you are right, it is not that exact.
  20. May 17, 2008 #19
    You just added air, reduced the density, and ensured a more efficient burning!:surprised
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