The Fresh Loaf

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Adding lime to corn meal for better nutrient absorption?

Sftobos's picture
Sftobos

Adding lime to corn meal for better nutrient absorption?

I'd like to use my electric gain mill to grind corn into meal to use as a whole grain cereal or to make polenta. Yet I know lime is often added to such dishes, I think because the nutrients in the corn aren't otherwise absorbed adequately. Can someone tell me more about this and advise me? Thanks. 

Toad.de.b's picture
Toad.de.b

Google "Nixtamalization" -- the process that turns cornmeal into masa for tortillas.  It is a common and ancient treatment of dried corn kernels.  It doesn't involve citrus lime but so-called "limewater" which was originally (and still used by traditionalists*) wood ashes but now slaked lime = CaOH.  Corn for polenta is not treated in this way.

Phytic acid presents a mineral-binding anti-nutritional issue in wheat products, particularly where doughs are not fermented.  In rural Punjab, for example, the traditional diet heavy on chipatis robs minerals (zinc for one, if I recall correctly) from consumers.  I am not aware of this problem with corn, but I'm not an expert in this particular area.  When I was in grad school, one of my fellow students was working on a wheat breeding project to reduce phytic acid in seeds, to ameliorate this problem in South Asia.  That's how I know about it.

Finding the right corn to mill into meal might be a challenge.  Popcorn is extremely hard and, I've heard, presents a threat to the integrity of some home mills.  Perhaps you can find whole corn, grown for human consumption (assuming you're not looking for Atrazine as a nutritional supplement :-) in bulk bins somewhere.  Otherwise Google "Whole Organic Corn" and you can find it for sale by mailorder from the usual sources.

Tom

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*The best hominy I've ever had was a gift from one of my students who came from a farm on which her dad would use ashes from the family's woodstove to lime a portion of his dried field corn every year.  Much better than canned supermarket hominy.

Sftobos's picture
Sftobos

Tom, thanks much for this note.  In your paragraph about nixtamalization, you mention “Corn for polenta is not treated in this way.”  Do you have a sense of why this is? Just an Old Guy points out that many modern diets have adequate amounts of niacin and other nutrients thus rendering nixtamalization potentially less necessary in the modern world, so why would it still be advocated in the making of tortillas (or hominy?) but not for corn used to make corn meal or polenta? Thanks. Very new to all of this. 

Justanoldguy's picture
Justanoldguy

Dent or flint corn is really hard to find anywhere other than the web and Toad.de.b is right about popcorn being wrong for many mills. I'm getting ready to try the nixtamalization experiment my self. When it comes to finding the lime required there are two sources, Mexican markets and in the canning supplies at grocery stores. In the Meexican markets it will usually be labeled "Cal" for calcium hydroxide, and in the stores as Pickling Lime. The original process used water and wood ashes to produce lye for making hominy.  

charbono's picture
charbono

 

Sftobos,

 

 

I'm not sure if you're asking about nixtamalization or if you're asking about simply adding lime to cornmeal.

 

 

You can google nixtamalization. I no longer do it because it's resource-intensive. I do, however, add a little lime to my maize porridge, for both flavor and a little extra calcium. I even add a little to masa harina. Adding more than an eighth tsp per cup of meal causes the color to begin to darken. I do not add lime to cornbread, as I don't think it improves the flavor.

 

Sftobos's picture
Sftobos

Thanks for the comments and Nechem, thanks for the article which I read.  I also read this article which explains the process of nixtamalization.  The thing I'm puzzled about is why nixtamalization is beneficial and important if you're making tortillas but not so necessary for corn meal.  I know if you're making tortillas, you bring the whole, unground corn kernels to a boil in water, add the calcium hydroxide, then let it sit overnight.  With cornmeal, you of course grind the grain first.  But it seems with cornmeal you still have the issues of phytic acid, inadequate absorption of niacin, a less than ideal protein profile - the purpose of nixtamalization is to remedy these -- so why isn't it necessary for cornmeal?  

Justanoldguy's picture
Justanoldguy

I think the primary reason it's not 'necessary' is largely the extensive range of foods available in modern developed countries. The problem of niacin deficiency and pellagra was exacerbated by the limited diet found in many regions and countries in the past where corn was the primary grain and a very large part of the overall diet. Most commercial corn meals now have some type of enrichment to compensate for the absence of niacin. You can also purchase meal made from corn that has been nixtamalized. It is sold as Masa Harina and I have used it mixed with regular meal to make cornbread. If you nixtamalize your own whole corn and dry it to a level appropriate for milling you can make it yourself.

charbono's picture
charbono

Aside from nutritional issues, nixtamalization is required in order to make a cohesive dough.  Untreated corn flour and water will not hold together.  It's also required for the flavor.

Justanoldguy's picture
Justanoldguy

As charbono points out flavor and preparation for making the tortilla dough are the primary purposes. There is perhaps one other problem that the process deals with, the presence of certain toxins produced by fungal agents that can be present in dried corn. Home ground corn meal will also have one other issue that you should take into consideration. The oil present in the germ will quickly develop rancidity. Commercial producers of cornmeal generally remove the germ before packaging. Here's the ingredient list from a package of yellow corn meal now resting in my pantry almost undisturbed:

Degerminated yellow corn, thiamine mononitrate, riboflavin, niacin, reduced iron, folic acid.

In other words they have to compensate for the deficiencies commercial preparation produces and entails. I regularly grind my corn to make cornbread, polenta (I'm from the South and polenta is the scientific name for grits) and johnny cakes. The flavor and aroma of products prepared from freshly ground corn is significantly superior to any off-the-shelf product. Grind only what you need for the item you're preparing and you'll get maximum flavor from your item. If your concern is primarily nutritional eat more tortillas. Hope this helps.

Toad.de.b's picture
Toad.de.b

Sftobos, I think you've got all your answers already.  Thanks for the link to Selene River Press.  There's some interesting information in that article, and some that I'd prefer to see some references for.  It would be hard to prove that Columbus didn't bring the nixtamalization process back with him.  Whether he did or not, Europeans didn't need a process to impart baking integrity to this New World cereal, maize  -- they already had glutinous wheat and rye (which the New World didn't, yet).  So they were happy to make grits (the scientific name for polenta :-) which were and are mushy and not kneadable.  Indeed, polenta is prevented from congealing into any kind of pancake when made in Italy by use of a Polentina, a device that is not available in the US (or anywhere with 110v/60hz electric) unfortunately that I'm aware of, despite my efforts to talk Williams-Sonoma and Consiglio's into finding a manufacturer.  The polentina continuously stirs the polenta in a copper bowl for up to an hour depending on whose kitchen it's operating in.  And for what it's worth, proper Lombardian polenta has some (10-20%?) buckwheat grits in it, in which case it's called "Saracena".  In fact, I saw shelves and shelves of the stuff in shops in the Valtellina valley of Italy just today as we were driving through.

Justanoldguy sounds like your expert on processing raw corn into cereal and polenta.  And that Selene River article lists some sources of corn meal and probably raw corn as well.

Tom

Sftobos's picture
Sftobos

Tom, your point is interesting and important.  If I'm understanding you correctly, you're saying that separate from the use of nixtamalization to make the niacin more available, potentially disable any mycotoxins, etc., the possibly most important use for nixtamalization in the Americas was to allow the mixture to be formed into dough (since corn doesn't contain gluten?)  In Europe, where the use of glutinous and therefore bread-forming grains such as wheat and rye was already established, they didn't need to use the newly-imported New World maize to make anything dough-y like bread or pancakes -- or tortillas as the Americans were doing. Good history lesson.

So typically modern Europeans, when making whole-grain corn meal and polenta, don't use any process similar to nixtamalization?

Toad.de.b's picture
Toad.de.b

I don't know of any treatment given to corn in Italy for polenta, before or after milling.  The only tweak I'm aware of is that, in northern Lombardia, it is often mixed with coarse buckwheat (saracena) flour to make taragna.

I'm no authority on food history but I do recall reading somewhere what I wrote above about the Old and New World's history and traditions of dough-forming flours, wheat/rye vs. nixtamalized corn.  Perhaps I read it in Hal Magee's On Food and Cooking or the sequel, since I've learned a lot about food science and history from his writings.  Whether ancient central American cultures nixtamalized corn to disinfect it, increase its nutrient value or enhance its cooking quality would be a tough culinary anthropologic nut to crack.  Traditions form by diverse and obscure mechanisms, lost to history in cultures with such scant written records.

Tom

Sftobos's picture
Sftobos

Thank for the comments.  Justanoldguy, just to confirm: when you grind your corn to make cornbread and polenta, you don't nixtamalize at all, either the whole corn before grinding or the corn meal after grinding?  

Sftobos's picture
Sftobos

The idea of adding course buckwheat flour to corn meal is enough to make me want to move to Lombardy. I think those two foods would go together beautifully, and I see no reason why my new grain mill can’t make it happen.