Daily Archives: 11/04/10

Toy with a Thousand Uses IV

Reader Scott writes:

Use number n + 1 for your sous vide machine: maize nixtamalization. Add calcium hydroxide and protease enzymes and set the sous vide to mid 50’s C for efficient proteolytic activity!

Holy cow, I had no idea this thing was so versatile! Hear that, honey? Your husband just bought us a miracle machine. Thanks Scott!

UPDATE: Thanks to reader Chris who pointed out that I originally jumped from 3 to 6 in my Roman numerals! Sister Joan Clare would have been so disappointed in me!

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Nixtamalization and Nutrition

The functional advantages of nixtamalization are just the beginning of what the process brought to the ancient Mesoamericans. For in the process of making their corn easier to handle and eat, Mesoamerican cooks accidentally unleashed a torrent of nutrients that would otherwise have been unavailable to them. For nixtamalization, it turns out, vastly increases the amount of free niacin present in corn, and renders the protein that it contains much more absorbable by the body.

What’s niacin? We know it as vitamin B3. It’s an essential nutrient, without which the body’s metabolism begins to slow down. Left unchecked a severe niacin deficiency leads to a disease called pellagra. What’s pellagra? Well, Europeans — especially Italians — found out all about it when they imported corn from the New World but not the nixtamalization process. Poor people who subsisted on nothing other than corn polenta began to exhibit skin rashes (the word “pellagra” is Italian for “rough skin”), weakness and in the worst cases dementia and death. Terrible stuff, pellagra, and it wasn’t just limited to Italy. The southern U.S. had tremendous problems with it until pellagra’s cause was finally identified in 1938.

But back to Mesoamerica. So what happened when the peoples of that region started eating corn that was suddenly rich in vital nutrients? Pretty much what you’d expect. Malnutrition decreased and populations increased. So powerful was the effect of nixtamalization, or so many historians speculate, that it allowed the tribes of Mesoamerica to grow into societies, the societies to grow into civilizations, and the civilizations to build great cities like Tikal and Teotihuacán.

Could a silly thing like a handful of wood ash dropped into a bowl of wet corn do all that? It seems it can. Very likely, it did.

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Oil in Flour Tortillas

Reader Mary Sue writes:

My abuelita began making her white flour tortillas with cooking oil instead of shortening after my abuelito’s third heart attack. She uses about 1/3rd of a cup of oil, these days canola or sunflower. Of course, it being a grandmother recipe, she’s been eyeballing it for decades and there’s no actual measurement involved.

And of course, blistered is the only good and proper way to cook tortillas. The store-bought plastic tasting ones are underdone.

Thanks for the message — and the backup — Mary Sue!

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What’s the difference between corn meal and corn masa?

It’s a good question, because on an intuitive level one would think that if a corn tortilla is a simple pancake made of ground corn, there really shouldn’t be that much difference between finely ground corn meal and masa harina (literally “dough flour”). In reality there’s a huge difference, which can be summed up in a single word: nixtamalization. Yeah, that’s a mouthful. It comes from the Aztec word “nixtamal” which, loosely translated, means “ash dough.”

Not very appetizing by the sound of it. However what ancient Mesoamericans discovered 3,500 years ago is that when you boil and then soak raw corn kernels together with ashes, some very interesting things happen. Notably, the outer hulls (pericarps) of the kernels loosen to the point that they can be slipped off. Further, what’s left — the endosperm and germ of the kernels — becomes quite soft and pliable, easily ground into a dough that’s perfect for making tortillas.

So nixtamalization is all about heat and water then? Er, not quite. The key component is really the ash, which, long-time readers of joepastry.com may remember, has a high pH. Add a handful to a pot of water and you get an alkaline solution that goes to work dissolving the glues that hold the walls of the pericarp cells together (the hemicellulose and pectins). The pericarp loosens and falls off, and the endosperm swells as it takes in more and more of the chemical-laden water. As it does, the tight bundles of starch molecules in the endosperm start to come apart. What you get, once the corn is finally drained and washed, is a processed corn product that’s easily ground into a dough that’s just smooth enough and just elastic enough to be formed into a thin cake like a tortilla.

Neat. But it raises the question: how did the ancient Mesoamericans hit on this process? Unknown. It may have started when someone mixed a few wood ashes in with some corn gruel (a common technique that indigenous American peoples used to lighten — really leaven — cakes made from grains). But who knows? Wood ashes (which contain potassium carbonate) weren’t the only alkaline compounds available to the peoples of that time. Naturally occurring lime (calcium carbonate-rich limestone and/or chalk deposits) were also used, as were the ashes of burned mussel shells.

These days, most people who want to make their own corn masa use a commercially-made product that simply goes by the name of “cal” in Mexico. Calcium hydroxide is what it is, commonly known as “slaked” (dissolvable) lime in America. It can be found in most Mexican markets in the spice section.

Buying the cal and boiling and steeping the corn is the easy part, however. The real challenge when it comes to making one’s own corn masa is the grinding. Getting it fine enough to make tortillas is no easy task. Food processors aren’t good enough. What’s needed is either a plate grinder or a good, old-fashioned metate. I’ve never used one, but I can imagine they call for more elbow grease than I’d be willing to put in for home-made tortillas. But those of you who might be interested, knock yourselves out! You can get them in Mexican markets as well. They cost less than you’d think.

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Butter in Flour Tortillas?

Reader Veggie asks if it’s possible to substitute butter for shortening in flour tortillas. The answer is yes, and I expect butter would give flour tortillas a very nice warm and toasty flavor, though it won’t be anything like what most people are accustomed to. A down side to using butter is that it’s 17% water (shortening is 0% water), which means there’ll be more activated gluten in the finished dough than there would otherwise be, so the dough will be a little more elastic and more difficult to roll.

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