Wednesday, July 13, 2011

Corn, carbon and hair

Sweet, creamy elote dip made from fresh summer corn

A friend of mine asked me to write a dip recipe for the 4th of July.  Oops. Well, it’s still July isn’t it?  I based this recipe on one of my favorite foods that I’ve been introduced to since moving to Texas.  Termed “elotes”, which simply means corn in Mexican Spanish, these delectable treats are served in Dallas at roadside stands and adjacent to taco joints.  In a Styrofoam cup, corn kernels are layered with butter, sour cream, cheese, hot sauce and lemon pepper.  Certainly not a diet food, but my husband and I fell immediately in love with this local fare and even asked our caterer to make a fancy version for our wedding which was a huge hit.

This dip uses some sour cream and mayo but the creaminess is amped up by the corn itself, half of which is pulsed through a food processor to make almost a corn pudding-like consistency.   The dip is topped with a thin layer of cotija cheese, a salty dry cheese, not unlike a high quality Kraft parmesan.  The whole thing is baked for a nice gooey texture and served with corn chips.

I was asking my friend Heather if she thought this was too much corn for an appetizer.  She made an interesting point about a documentary she saw, King Corn, in which scientists used radioactive isotopes to trace about 50% of the carbon that we consume as Americans to corn.  As carbon, hydrogen and oxygen are the basis for carbohydrates, fats as well as amino acids and thus energy, it is quite remarkable how corn dependent our food chain is. 

The scientific methods used to trace the foundations of humans’ diet are fascinating and use human hair as the tissue of study.  Hair leaves an excellent footprint of what we eat—it is metabolically inactive, is derived from what we consume and immediately reflects changes in diet. This excellent article in the UVA magazine biographies one of the major scientists, Stephen Macko who helped advance research in using hair to trace the origins of diets, even using mummy hair to deduce food consumption among ice men and paleo humans.  He also helped the filmmakers of King Corn use their hair to measure the amount of corn in their diet. 

Using various concentrations of variations of carbon, nitrogen and sulphur, known as isotopes, scientists can deduce the biologic origins of humans’ diets.  Corn is rich in the 13C isotope, thus allowing scientists to trace corn as it escalates in the food chain.  Scientists also use 15 nitrogen isotopes, which increase in an animal that eats a plant, then in a human who eats that animal, to track the amount of meat somebody is consuming in their diet. 

In the US, most livestock is corn-fed, thus meat is a large contributor to the corn carbon isotopes.  In fact, it has been demonstrated that when somebody moves from the UK to the US, their carbon isotopes from corn increase by approximately 3%.  A 2008 study from the University of Hawaii traced the carbon isotopes of various fast foods, and after a survey of various restaurants throughout the US, only about 5% of the chicken and beef were not solely corn fed; also many of the fries contained large amount of corn isotopes. 

The politics behind corn growth, production, alteration and consumption is a heavy debate--one that represents many levels of lobbying, industry and culture.  It cannot be denied that corn is pervasive and permanent in our daily lives.  Surely though, it is not corn in its unaltered form, such as this delicious elote dip, that calls for concern.  What is alarming however, are the ways that corn is manipulated and passed through the food chain and can produce potentially damaging effects on health, the economy and the ecosystem. 

Elote Dip

4 ears corn, grilled, roasted or steamed, or 2 cups frozen corn defrosted
¼ cup mayo
¼ cup sour cream
¼ tsp cayenne
juice of ½ lemon
¾ cup grated cotija cheese (or if you cannot find this anywhere, grated parmesan)
1 tsp black pepper
2 tbsp Mexican hot sauce, such as Bufalo (or substitute for 1 tbsp Louisiana hot sauce)

Preheat oven to 400.  Cut corn off cob.  In blender or food processor place half kernels, mayo, sour cream, cayenne, lemon juice, pepper, hot sauce, pepper and ½ cup cotija cheese.  Blend until smooth.  In heatproof dish, combine blended mixture with the other half of whole corn kernels.  Top with leftover cheese.  Bake for 20-25 minutes or until brown and bubbly.  Serve with tortilla chips.

Macko, SA.  Engel, MH, et al.  Documenting the diet in ancient human populations through stable isotope analysis of hair. Philosophical transactions PHILOSOPHICAL TRANSACTIONS- ROYAL SOCIETY OF LONDON SERIES B BIOLOGICAL SCIENCES. 1999, VOL 354; ISSUE 1379, pages 65-76

McCullagh, J et al.  Carbon isotope analysis of bulk keratin and single amino acids from British and North American hair.  Rapid Commun. Mass Spectrom. Volume 19, Issue 22, pages 3227–3231, 30 November 2005.

Jahren, A, Kraft R.  Carbon and nitrogen stable isotopes in fast food: Signatures of corn and confinement. PNAS November 18, 2008 vol. 105 no. 46 17855-1786

Petzke, KJ et al. Carbon and nitrogen stable isotopic composition of hair protein and amino acids can be used as biomarkers for animal derived dietary protein intake.  J Nutr. 2005 Jun;135(6):1515-20.

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