The spice of life

nice work if you can get it

Nuclear chicken science
One way to make meat taste better is to marinate it in a soup of spices, oil, sugar and water. Two years ago, chemist Mark Knize of Lawrence Livermore National Laboratory stumbled across an unexpected benefit of marinades while looking into the formation of heterocyclic aromatic amines (HAAs) while chicken is cooked.

HAAs have been suspected of causing cancer since the 1920s and 1930s, when workers in dye factories came down with the disease after contact with the large, organic molecules. According to Knize, HAAs cause their damage by sticking to DNA and causing mutations as the DNA replicates.

In 1996, while wandering through a street fair in his home town of Tracy, Calif., Knize bought some chicken-on-a-stick and returned it to the lab for testing. He was surprised to find that the well-done meat had far lower levels of HAA than samples he'd cooked in the laboratory. (You get to teach school or type letters for a living. This guy grills chicken. Who said life was gonna be fair?)

Nobody. Get on with the story!
Ignoring that pressing question, Knize wondered why the street food had such low levels of suspected carcinogens. Eventually, his laboratory tests credited the marinade in which the chicken had been dipped before cooking.

brushTheir interest piqued, the researchers cooked up a marinade of their own, and got another drastic reduction in the bothersome HAAs. But what part of the marinade? As you'd expect from what you've already read, garlic immediately came under suspicion, but it proved relatively impotent.

It turned out that the thicker components of the marinade -- primarily oil and sugar -- were coating the chicken and somehow gumming up the high-temperature dehydration reactions that form HAAs. "The whole process is prevented by moisture, somehow," says Knize. But he admits that "It's hard to come up with a mechanism."

The marinade technique also seems to work with steak, he adds, and could be useful whenever meat is cooked at high temperature, either over a grill or in a frying pan. Roasting in the oven and boiling are too cool to make HAAs.

Although Knize's group continues studying the problem -- trying to nail down exactly how many people might be getting sick from HAAs in food -- they declined an opportunity to expand their research last year when the street fair offered breaded and fried alligator. The 'gator was not cooked in a way that would make the HAA he studies, Knize notes. And there was another problem: "It's pretty hard to get reimbursed for street food, and I chickened out."

Don't chicken out on us. How 'bout checkin' out a fascinating "how-come" theory of spices...


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