From teosinte to corn
Is it maize or is it corn? In North America, Australia and New Zealand, maize means corn and vice-versa. In the UK and Europe, corn refers to any locally-grown grain (e.g. wheat, rye, oats, barley). The etymology comes from the verb corn “to salt” (circa 1560). Hence corned beef means salted beef. Originally referring to the grains of salt, the use of the word corn widened to refer to grains of cereal, and then specialized (in some regions) to refer just to maize.
For one of the big three food staples (after rice and wheat), maize comes with a catch. A diet dependent on maize can be deadly, and it was, right up to the start of the 20th century in some places, notably southern regions of North America.
While maize is nutritious, its micronutrients are locked up in the grains very tightly, and our digestive system cannot access them even when the maize is thoroughly cooked. The kernels can pass through our digestive system remarkably intact.
When Columbus brought maize back to Europe, he neglected to bring with him a little trick that the Native Americans had developed to unlock its nutrients, particularly niacin, and make them digestible.
They developed a process called nixtamalisation (from an Aztec word), whereby maize was cooked in an alkaline solution (ash or lime). This results in maize nutrients becoming accessible to our digestive system.
How they discovered this is unknown, however, without maize undergoing this process it would be a mistake to call it food. In southern regions of Europe and North America (also Africa), as poverty grew, the most vulnerable people became dependent on maize as a cheap staple, supplementing it with not a lot else (molasses and fat in North America). Without knowledge of nixtamalisation, the niacin was locked in the grains, and these people developed a niacin deficiency that led to pellagra (characterized by severe dermatitis, diarrhea, dementia and death).
It wasn’t until 1914 that Joseph Goldberger showed that maize only appeared to be a staple, and alone could not sustain health. He did this, in the spirit of the times, by experimenting on prisoners. He later suggested that supplementing maize with yeast (which as it happens is high in niacin) was protective. His work was largely ignored until the depression years, when the American Red Cross distributed yeast to supplement maize. It was not until 1937 that the missing nutrient, nicotinic acid, later renamed niacin, was isolated.
Nixtamalisation also builds proteins, and adds calcium (from the cooking liquid) to the diet that also gels starches and makes possible corn-dough (e.g. for tortillas, tamales and corn-chips). Finally, it breaks down some of the corn oil into more digestible molecules (mono- and diglycerides), which are also good emulsifiers, further improving doughs.
It was a remarkable and almost unlikely discovery by our forebears.
And that’s not all they did. Maize underwent drastic selective breeding over thousands of years. It started out as an unpromising grass called teosinte about 7–10,000 years ago in Mexico. Over a period of steady human-driven genetic modification, it emerged as the maize we know today. To give an indication of how striking this GM process turned out to be, here’s the comparison:
The sad irony is that teosinte itself is now an endangered species, and efforts are underway in Mexico to protect it in reserves.
Sweetcorn is the most common whole-variety for human consumption. While this is not subject to nixtamalisation, we eat it mostly for its sweetness and flavour. Our diverse diet provides the nutrients that we don’t extract from the corn.
Sweetcorn loses it sugars (converting to bland starch) almost immediately on harvest, and at a dramatic rate. Even if bought from a farmer’s market, that’s too long a delay. Modern harvesting chills and snap-freezes the corn almost immediately and preserves sweetness. Hence, the sweetest sweetcorn is in the freezer compartment of the supermarket. The same applies to green peas. Frozen is best, unless its growing in your backyard.