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Pat Coghl
#1 / 38
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 How is food affected by microwaves A co-worker of mine is married to a biomedical engineer who claims that we don't know enough about microwave ovens' affect on foods to be able to claim that they are safe. He says that the high energy waves actually change the molecular structure of most foods. I had always thought that the microwaves only cause the water molecules
in the fool to vibrate. Is it possible that there is actually a risk to
eating microwave-heated cooking.net">food (apart from burning yourself that is)?
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| Mon, 13 Oct 1997 03:00:00 GMT |
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hi..
#2 / 38
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How is food affected by microwaves Quote:
>A co-worker of mine is married to a biomedical engineer who claims >that we don't know enough about microwave ovens' affect on foods to >be able to claim that they are safe. He says that the high energy >waves actually change the molecular structure of most foods. >I had always thought that the microwaves only cause the water molecules
>in the fool to vibrate. Is it possible that there is actually a risk to
>eating microwave-heated cooking.net">food (apart from burning yourself that is)?
I've heard some people express concern that microwaving cooking.net">food in plastic or styrofoam containers not designed for microwaving could leach some chemicals into the food. So, I generally use glass or microwaveable china, or containers marked as microwaveable.
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| Mon, 13 Oct 1997 03:00:00 GMT |
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Hank Rober
#3 / 38
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How is food affected by microwaves Quote:
>>A co-worker of mine is married to a biomedical engineer who claims >>that we don't know enough about microwave ovens' affect on foods to >>be able to claim that they are safe. He says that the high energy >>waves actually change the molecular structure of most foods. >>I had always thought that the microwaves only cause the water molecules
>>in the fool to vibrate. Is it possible that there is actually a risk to
>>eating microwave-heated cooking.net">food (apart from burning yourself that is)?
>I've heard some people express concern that microwaving cooking.net">food in plastic
>or styrofoam containers not designed for microwaving could leach some
>chemicals into the food. So, I generally use glass or microwaveable
>china, or containers marked as microwaveable.
A few years ago there were some newspaper articles locally, including mention of a researcher at Lawrence Livermore labs in Berkeley who was looking at actual chemistry of foods cooked in microwave and heat. I recollect one tidbit I put into practice; drain off the first juices
that appear when microwaving meat, til it's hot through, rather than
leaving it all in the pot, to remove some {*filter*} chemical product that
shows up early from the microwaved fat.
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| Mon, 13 Oct 1997 03:00:00 GMT |
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p..
#4 / 38
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How is food affected by microwaves Quote:
>>>A co-worker of mine is married to a biomedical engineer who claims
>>>that we don't know enough about microwave ovens' affect on foods to
>>>be able to claim that they are safe. He says that the high energy
>>>waves actually change the molecular structure of most foods.
>>>I had always thought that the microwaves only cause the water molecules
>>>in the fool to vibrate. Is it possible that there is actually a risk to
>>>eating microwave-heated cooking.net">food (apart from burning yourself that is)?
>>I've heard some people express concern that microwaving cooking.net">food in plastic
>>or styrofoam containers not designed for microwaving could leach some
>>chemicals into the food. So, I generally use glass or microwaveable
>>china, or containers marked as microwaveable.
>A few years ago there were some newspaper articles locally, including
>mention of a researcher at Lawrence Livermore labs in Berkeley who was
>looking at actual chemistry of foods cooked in microwave and heat.
>I recollect one tidbit I put into practice; drain off the first juices
>that appear when microwaving meat, til it's hot through, rather than
>leaving it all in the pot, to remove some {*filter*} chemical product that
>shows up early from the microwaved fat.
Hi, Think about it! The microwaves heat up water molecules by vibration. These molecules in turn heat up the cooking.net">food particles. Microwave changes the food's molecular structure no more than conventional heating does. Beware, though, that microwave heating starts from where water molecules are, ie, not necessarily at the surface. In contrast, conventional heating always starts from the surface. Peter
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| Mon, 13 Oct 1997 03:00:00 GMT |
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Joel Kolst
#5 / 38
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How is food affected by microwaves
Quote:
>A co-worker of mine is married to a biomedical engineer who claims
>that we don't know enough about microwave ovens' affect on foods to
>be able to claim that they are safe. He says that the high energy
>waves actually change the molecular structure of most foods.
Guess what? cooking cooking.net">food in a (convection) oven actually changes the molecular structure of most foods too! Horrors! Horrors!
Just by looking, most people can tell that a cooked chicken is somehow no
longer the same as a raw chicken...
Microwaves work through the dielectric absorption of the microwaves. Water
absorbs quite well, although plenty of other types of cooking.net">food "stuff" does too
(the idea that a microwave is tuned to the resonant frequency of
water is a myth).
Quote: >I had always thought that the microwaves only cause the water molecules
>in the fool to vibrate.
Nope, water just happens to vibrate especially well. Quote: >Is it possible that there is actually a risk to >eating microwave-heated cooking.net">food (apart from burning yourself that is)? Well, we don't know everything about anything, so there's always some risk, but I'm not aware of anyone who's every come up with a scientific reason for why microwave cooking is any more dangerous than convection cooking. But I'd love to hear anyone else's ideas...
This is probably a sci.physics FAQ...
---Joel Kolstad
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| Mon, 13 Oct 1997 03:00:00 GMT |
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Phillip Burge
#6 / 38
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How is food affected by microwaves Quote:
>A co-worker of mine is married to a biomedical engineer who claims
>that we don't know enough about microwave ovens' affect on foods to
>be able to claim that they are safe. He says that the high energy
>waves actually change the molecular structure of most foods.
ALL cooking, microvave OR conventional, changes the molecular structure of food. This is just another "frankenfood" scare. --
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| Mon, 13 Oct 1997 03:00:00 GMT |
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Hank Rober
#7 / 38
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How is food affected by microwaves Quote:
>>A few years ago there were some newspaper articles locally, including
>>mention of a researcher at Lawrence Livermore labs in Berkeley who was
>>looking at actual chemistry of foods cooked in microwave and heat.
>>I recollect one tidbit I put into practice; drain off the first juices
>>that appear when microwaving meat, til it's hot through, rather than
>>leaving it all in the pot, to remove some {*filter*} chemical product that
>>shows up early from the microwaved fat.
>Hi,
>Think about it! The microwaves heat up water molecules by
>vibration. These molecules in turn heat up the cooking.net">food particles.
>Microwave changes the food's molecular structure no more than
>conventional heating does. Beware, though, that microwave heating
>starts from where water molecules are, ie, not necessarily at
>the surface. In contrast, conventional heating always starts
>from the surface.
>Peter
i think this illustrates the difference between theory (null hypohesis, there will be no difference between treatments) and research. I'll try to find a citation or press reference for you this weekend.
Do note one obvious difference -- no browning reaction in microwaving;
so you don't get the 'caramelized' flavor, you get a different set
of byproducts.
Kx
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| Tue, 14 Oct 1997 03:00:00 GMT |
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Pete
#8 / 38
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How is food affected by microwaves Quote: >Microwaves work through the dielectric absorption of the microwaves. Water >absorbs quite well, although plenty of other types of cooking.net">food "stuff" does too >(the idea that a microwave is tuned to the resonant frequency of >water is a myth). >>I had always thought that the microwaves only cause the water molecules
>>in the fool to vibrate.
>Nope, water just happens to vibrate especially well.
Hi, Sorry but the microwave frequency for household use is actually tuned to be in the highest absorption range of water. Call it the resonant frequency range if you like. The peaks of the absorption are actually in the infrared range (of conventional heating) but then the electromagnetic energy penetration wouldn't be as deep and it'd take longer to cook. Water molecules are dipolar and hence they respond well to electromagnetic
waves. You were right there.
Peter.
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| Tue, 14 Oct 1997 03:00:00 GMT |
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01928374
#9 / 38
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How is food affected by microwaves
: I had always thought that the microwaves only cause the water molecules : in the fool to vibrate. Is it possible that there is actually a risk to : eating microwave-heated cooking.net">food (apart from burning yourself that is)? What a neat idea, putting fools in microwave ovens!
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| Tue, 14 Oct 1997 03:00:00 GMT |
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Dave Zimmerm
#10 / 38
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How is food affected by microwaves Quote:
> A co-worker of mine is married to a biomedical engineer who claims > that we don't know enough about microwave ovens' affect on foods to > be able to claim that they are safe. He says that the high energy > waves actually change the molecular structure of most foods. > I had always thought that the microwaves only cause the water molecules
> in the cooking.net">food to vibrate.
The microwaves in a microwave oven are tuned to a frequency that water absorbes readily. The energy e{*filter*}s the water molecule, heats it up, and that heat is transfered to the surrounding molecules, whatever they are. Microwaves are not ionizing radiation, and it's been repeatedly shown that at the frequencies and energies used, kitchen microwave ovens can't do more than create heat. (No, I can't quote sources. But I'm pretty sure that CU has researched this at least once.) Dave
--
------------------------------------
Dave Zimmerman, Z+ Computer Services
[ http://www.***.com/ ~zimm/zplus.html]
<*> You have forgotten something <*>
------------------------------------
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| Tue, 14 Oct 1997 03:00:00 GMT |
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Pete
#11 / 38
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How is food affected by microwaves
Quote:
>>>Microwaves work through the dielectric absorption of the microwaves. Water >>>absorbs quite well, although plenty of other types of cooking.net">food "stuff" does too >>>(the idea that a microwave is tuned to the resonant frequency of >>>water is a myth). >This is correct. Extra points to whomever wrote it.
>>Hi, Sorry but the microwave frequency for household use is actually
>>tuned to be in the highest absorption range of water. Call it the
>>resonant frequency range if you like. The peaks of the absorption
>This is dead wrong. What is this "highest absorption range of water"
>stuff? That doesn't even make sense. The 2.45GHz frequency is used
>because it's reasonably easy to generate and the FCC said it was ok!
>Whoever started this rumor that microwave ovens are "tuned" to any
>kind of resonant frequency of water has a lot of explaining to do.
>--
>David J. Heisterberg I am trying to do two things, viz.
>Department of Chemistry be a radical and not be a fool.
>The Ohio State University -- James A. Garfield
Here's the explanation: Take a quick look at any freshman electromagnetic book on the absorption property of water. For instance, try "Classical Electrodynamics," the engineering bible by J.D. Jackson, second edition, page 291. You'll find that the absorption coefficient of water reach its highest values from around 10^7 to 10^14 Hz. It then dips precipitously around the optical frequency (Mother Nature made full use of this special property of water or water vapor, making our eyes see in this range). Above around 10^15 Hz, the absorption rate shoots up again. Let's kill the rumor and present hard facts!
By the way, why is 2.45 GHz easy to generate? And why the FCC picked
this frequency? Hard facts, please.
Peter.
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| Tue, 14 Oct 1997 03:00:00 GMT |
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Obi Thom
#12 / 38
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How is food affected by microwaves Quote:
> A co-worker of mine is married to a biomedical engineer who claims > that we don't know enough about microwave ovens' affect on foods to > be able to claim that they are safe. He says that the high energy > waves actually change the molecular structure of most foods. > I had always thought that the microwaves only cause the water molecules
> in the fool to vibrate.
^^^^ Why don't you put him in the microwave and find out?
Seriously, I doubt that a structural change would occur in microwaved
food. Ask him for references to studies which make his point. If he gives
you any, please post them, because I'd like to read them.
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| Tue, 14 Oct 1997 03:00:00 GMT |
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David J Heisterbe
#13 / 38
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How is food affected by microwaves Quote:
>>Microwaves work through the dielectric absorption of the microwaves. Water >>absorbs quite well, although plenty of other types of cooking.net">food "stuff" does too >>(the idea that a microwave is tuned to the resonant frequency of >>water is a myth). This is correct. Extra points to whomever wrote it. Quote: >Hi, Sorry but the microwave frequency for household use is actually
>tuned to be in the highest absorption range of water. Call it the
>resonant frequency range if you like. The peaks of the absorption
This is dead wrong. What is this "highest absorption range of water" stuff? That doesn't even make sense. The 2.45GHz frequency is used because it's reasonably easy to generate and the FCC said it was ok! Whoever started this rumor that microwave ovens are "tuned" to any kind of resonant frequency of water has a lot of explaining to do. -- David J. Heisterberg I am trying to do two things, viz. Department of Chemistry be a radical and not be a fool. The Ohio State University -- James A. Garfield
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| Tue, 14 Oct 1997 03:00:00 GMT |
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Lon Stowe
#14 / 38
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How is food affected by microwaves Quote:
>Hi, >Think about it! The microwaves heat up water molecules by >vibration. These molecules in turn heat up the cooking.net">food particles. True. More formally, the microwaves are tuned to the proper frequency to make the water molecules in the substance vibrate. Items with no water in them don't get hot in a nuker. Quote: >Microwave changes the food's molecular structure no more than
>conventional heating does.
Although the original poster's theory that microwaved foods are dangerous, this isn't entirely true, as any pastry cook can see. The heating of water molecules does cause some quaint effects on some proteins like glutens and those in cheeses. Every tried to bake a cake or a pizza in the nuker? Bleccch. The subtle differences between microwave heating and ordinary heat as from a convection or conventional oven does make the glutens more glue like and cheese more like ghostbuster slime.
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| Tue, 14 Oct 1997 03:00:00 GMT |
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Obi Thom
#15 / 38
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How is food affected by microwaves Quote:
> >A co-worker of mine is married to a biomedical engineer who claims > >that we don't know enough about microwave ovens' affect on foods to > >be able to claim that they are safe. He says that the high energy > >waves actually change the molecular structure of most foods. > Guess what? cooking cooking.net">food in a (convection) oven actually changes the molecular
> structure of most foods too!
Is Pat speaking of cooking or just warming up already cooked food? I would be extremely surprised if merely warming up cooked food, which is probably what most folks do with their microwaves, has any effect at all on mole- cular structures. If Pat meant " cooking," then of course, molecular struc- ture is (and should be!) altered.
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| Wed, 15 Oct 1997 03:00:00 GMT |
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