Marinades Hold Off Cancerous Compounds

With the summer steak season in swing indoors and outdoors, cooks can season the meat on the grill and provide some protection against cancer all at the same time.

All it takes is marinating the steaks with certain herbs and spices. But before heading out to the grill, J. Scott Smith examined some possibilities in the laboratory. Smith, a professor of food chemistry at Kansas State University, investigated for the Food Safety Consortium what effect marinating steaks could have on reducing carcinogenic compounds known as HCAs.

“Heterocyclic amines (HCAs) in foods have been in the spotlight for many years,” Smith said. “They are carcinogenic and mutagenic compounds that are found at parts per billion levels in cooked fish and meats.”

Previous research has shown that grilled beef is a major source of dietary HCAs when cooked at temperatures from 375 degrees F (190.5 degrees C) and above.

Consuming dietary carcinogens has been associated with different cancers in humans and one of the HCAs was shown this year to cause prostate cancer in rats. Smith said that’s why it’s necessary to find ways to prevent HCAs from forming in cooked meats.

“Cooking meats with natural antioxidants decreases or eliminates HCAs on meat,” Smith said. Consumers have responded favorably to natural food products in recent years, including natural spices, such as rosemary, which are rich in antioxidants.

Smith’s research group began experimenting with marinades containing herbs and spices, notably those related from the mint family such as basil, mint, rosemary, sage, savory, marjoram, oregano, and thyme. Most of these herbs are rich in three compounds – carnosic acid, carnosol and rosmarinic acid – that are potent antioxidants.

“We believe that addition of various substances to the meat before cooking may reduce the carcinogenic HCAs,” Smith said. “Marinating steak before grilling is a practical way to reduce HCA contents of even well-done beef for many consumers.”

Smith’s group measured the HCAs in grilled round steaks and found that after marinating them with a commercial product containing rosemary and thyme, the cooked product’s level of reduced HCAs – an 87 percent decrease – correlated to the amount of antioxidants present in the marinades.

The marinade containing rosemary and thyme had the greatest effect on reducing HCAs, but two other marinades with different herbs seasonings were tested and found to be almost as effective. The rosemary/thyme marinade also contained pepper, allspice and salt. Another marinade included oregano, thyme, garlic and onion. A third marinade had oregano, garlic, basil, onion and parsley.

The marinades are all available in grocery stores. “These are the ones that are packaged as powders,” Smith said. “There are different brands. We followed the marinating instructions according to the label. We cooked it and it tasted fine.”

Consumers can also add the herbs/spices directly to their product, such as ground beef.

Smith intends to investigate other seasonings to determine their potency in reducing HCAs. “I plan on taking a look at a lot of them, probably about 20 of them. The major ones are in the mint family: basil, sage, thyme, oregano and rosemary. They have some similar properties,” he said. Other possibilities for research include parsley, fennel, paprika, nutmeg, cloves and cinnamon.

Smith also wants to look into what possible changes that the antioxidants could cause with regard to taste, texture and nutritional content, if any. Results so far, however, do not indicate any major alterations are taking place.