Sous Vide Corn on the Cob Question

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Joined Apr 5, 2007
Sorry, I didn't have a camera to snap a picture of this....

I was cooking some fresh cob corn the other night, bagged with about a cup of salted butter and a splash of mirrin.  I cooked them at 85 C for about two hours.  Really good, ftr, I am not a fan corn this way but this was a nice way of doing it.

The two ears that displayed this colour change had a somewhat longer stock end still attached, other than that no difference I am aware of.

Any theories?

Al
 
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What was the color change exactly? Was this white, yellow or  variegated corn? The two that changed were in the same pouch as the others I assume? 
 
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Yep, they were all yellow sweet corn.  The two that showed change added white, off-white, ruby red (and some variance of shades of red) and very dark (nearly purple).  Probably about 30% of the kernals showing some change in colour.  

They were all together in the same bag.
 
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Joined Jun 6, 2007
@AllanMcPherson you may have surreptitiously stumbled upon an interesting scientific principle here.....!

First, corn cod is a seed pod.  Each kernel are genetically different because they are seed for the next generation of plant.  we tend to think that each kernel is a clone of the plant because they are all the same colour but it is clear by looking at Indian corn that each kernel  is different

https://en.wikipedia.org/wiki/Flint_corn


The varying colours of Indian corn is mostly due to zeaxanthin content

https://en.wikipedia.org/wiki/Zeaxanthin

Now,  one fundamental principle of natural colour chemistry is that these compounds are unstable because they change colour with heat and pH.  I noticed you added Mirin which is acidic.  I would bet that the long slow cooking and mild acidity acted upon zeaxanthin and chemically changed it's characteristics and shade according to the content in each grain.  Lutein, another pigment could be also involved.

https://en.wikipedia.org/wiki/Lutein

another hypothesis is that you have hacked the cellular machinery of the corn kernels with your conditions and the results was a complex regurgitation of colouring mistakes because Zeaxanthin and Lutein are xantophylls, a class of chemicals are very similar yet come in a wide variety of colours (yello-orange-dark red to green). 

https://en.wikipedia.org/wiki/Xanthophyll

either way, cool experiment!!!

Luc H.
 
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I think you got a middle field cob. Our family loves red sweet corn. When any of us goes to the country they must bring some back. A couple of us have the roadside stands on our GPS.

We never boil corn. It's only done on the grill or in the oven. We have seen people boil the red corn and the color bleeds out. The sweet red is smaller kernel but is usually sweeter then  the white or yellow. The old farmers always told us it is really good for you.

Many times where the field would change varieties there would be a mix of kernels. Your corn may have had some hidden red kernels.

just a thought
 
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Luc,

Thanks for the info!  Next time I might try a higher concentration of acid (maybe more mirin, maybe a shot of lime or calamansi...)

The other thing I didnt mention was that the butter was cultured, any chance that could have reacted?  Thinking buttermilk poached corn could be pretty good...

Al
 
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not too much acidity in butter since it's 90% fat but buttermilk is plenty acid.

Luc H.
 
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Joined Apr 5, 2007
As I mentioned before, I am not a fan of corn on the cobb myself.  My wife, however, is very much so.  I am sure she will appreciate any experimentation in this regard!
 
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