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effects of a microwave on vegetable nutrients

Posted: Mon Jun 14, 2010 1:40 pm
by frigginwizard
I have been unable to to find a definitive answer as to what the effect of the microwave is on produce.

Any thoughts, links, etc?

Posted: Mon Jun 14, 2010 2:15 pm
by ApolytonGP
Pretty similar to steaming. The microwave works by the electrical waves interacting with the dipoles of the water molecules to move them back and forth (causing heat). You're unlikely to be changing too many structures of nutrients themselves unless you take the veggies to dessication and higher temps. In terms of nutrient retention, it's probably the best method (even better than steaming since you don't have what collects in the water). You'll get some easier digestion of some of the plants because of softening and all that.

I think it's basically pretty darn fine.

Go veggies!

Posted: Mon Jun 14, 2010 4:11 pm
by frogbyte
The dipole water thing is a myth. But yes microwaving is possibly the healthiest cooking because as long as things are covered it's almost impossible to burn stuff on accident. Course you end up with rather disgusting mush to eat.

Posted: Mon Jun 14, 2010 6:41 pm
by ApolytonGP
Yeah. Personally, I would use whatever appeals to you, tastewise. Sure, there are some ways of cooking veggies that are more nutritious than others, but as long as you are getting a LOT of veggies in and are doing some raw, some cooked...it'll all be good. Um...would watch out about a lot of oil or such if you are dieting.

Posted: Tue Jun 15, 2010 11:41 am
by synergy317
you destroy phyto-nutrients. I have read that steaming preserves more of them than all else.

Posted: Tue Jun 15, 2010 2:14 pm
by frogbyte
As long as things are covered microwaving is the safest steaming. Well, you can also do it on a stove top with a pot of boiling water, and then another pan set inside the first pot, hovering well above, so that it's only heated by the water and not indirectly touching the burner.

Posted: Tue Jun 15, 2010 9:21 pm
by Ryan A
frogbyte wrote:The dipole water thing is a myth. But yes microwaving is possibly the healthiest cooking because as long as things are covered it's almost impossible to burn stuff on accident. Course you end up with rather disgusting mush to eat.
I am sorry but the dipole of water is not a myth. It's true that the microwaves interact with more than just water dipoles but they do interact with the dipoles and that is how they create the heat.

Posted: Wed Jun 16, 2010 11:25 am
by frogbyte
Yes, microwave radiation interacts with water, and the dipoles of water may contribute to absorption in some part, but the myth is that there's something special about water. Microwaves heat many materials.

Posted: Wed Jun 16, 2010 11:31 am
by ApolytonGP
In most foods, it is pretty much the liquid water that gets interacted with (preferentially). Ice is harder for the waves to interact with.

f you have salt (and water), then the waves will interact very strongly with the ionic conductor. This can give you runaway heating of ham or hot dogs.

Waves will also interact with very thin layers of metal (like in a popcorn bag or the silvery surface on a pizza cooking disk. This allows higher than wate temps, so that you get crispening.

Waves can also interact with magnetic (or electrical) ferrites in special cookware.

Thick slabs of metal don't really interact with the waves (they reflect). For instance the sides of the cavity are reflectors.

Sharp edges of metal can cause sparking though.

Posted: Wed Jun 16, 2010 11:38 am
by Ryan A
The dipoles are the primary mechanism for energy transfer and anything with a dipole that is free to rotate/reorient will cause heat.

I am pretty sure ice is a worse candidate than water purely because water has a high specific heat relative most things. The heat gets dispersed through the material after the dipole relaxes faster in materials with higher specific heat.

Metals (conductors) will interact differently with the EM wave and so yes I would expect different behavior from them, including reflection and different types of absorption than the dipole mechanisms in most organic tissues.

Posted: Fri Jun 18, 2010 2:10 am
by anandsr21
Try to get a Microwave with an Inverter. Cooking at a low intensity provides better cooking. Normal Microwaves cannot do that.

Posted: Fri Jun 18, 2010 2:28 am
by Jungledoc
So, how about the original question? Do any of us have any idea? Probably not. I would guess that it has no significant effect on the nutrients other than making them hot. But that's just my guess.

Posted: Fri Jun 18, 2010 8:45 am
by Nevage
I was taught in my nutrition lectures that apart from steaming, microwaving is the best way to cook vegetables for conserving nutritional content.

Posted: Fri Jun 18, 2010 8:49 am
by ApolytonGP
I like this comment:

"But let’s not get too lost in the details. Vegetables, pretty much any way you prepare them, are good for you, and most of us don’t eat enough of them. And the microwave oven? A marvel of engineering, a miracle of convenience — and sometimes nutritionally advantageous to boot."

In this link: http://www.health.harvard.edu/fhg/updat ... tion.shtml

See also this link:

http://heraldextra.com/lifestyles/artic ... d45c5.html

Posted: Fri Jun 18, 2010 9:06 am
by frigginwizard
the majority of vegetables that I eat are frozen, and I have always used the microwave to thaw them out. So I was curious, thanks for the answers guys.