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Researchers at AU are Looking for the Key to Predicting Beef Tenderness
AUBURN, Ala. - Predicting how tender a cut of beef will be can be like rolling dice, but meat scientists at Auburn University are working to uncover some of the mystery of meat tenderness.
Elisabeth and Steven Lonergan, both assistant professors of animal and dairy science in Auburn University's College of Agriculture, are studying the aging process of beef in hopes of discovering the key to predicting tenderness.
"We would like to be able to define biological factors that explain a wide variation in beef tenderness," said Steven.
In a study that began in the spring of 1996, the Lonergans looked at the relationship between calpastatin activity and tenderness in meat from Brangus bulls and steers.
Calpastatin inhibits calpain, an enzyme that selectively degrades muscle proteins, making meat more tender. Therefore, meat with higher calpastatin activity tends to be less tender, and vice versa.
Steaks from the bulls and steers were tested for changes in tenderness, calpastatin activity and muscle protein degradation. The goal was to pinpoint the time frame after death in which calpastatin activity would be most significant. "We're looking for what changes are taking place in the muscle and how we can predict how long we have to age beef," Steven said.
Though Brangus beef tends to be somewhat tougher early post mortem, they found that after 14 days of aging, the meat is significantly tenderized.
"We found that some animals tend to tenderize faster than others during this aging period," Elisabeth said.
An understanding of what happens during the aging process in relation to beef tenderness might help processors to know at what point beef should be put on the market, she said. They would like to come up with a test or an indicator that could predict which live animals would tenderize fastest after slaughter.
In another study, Angus x Simmental cows were bred to either Gelbvieh, Hereford or Limousin bulls.
After slaughter, the short loin was evaluated for tenderness after two, seven and 14 days. Though there were no differences in the ultimate tenderness after 14 days of aging, there could be differences in the rate of aging among different animals, Steven said.
In this cross bred study, they found that there was more variation in tenderness within a breed than across breeds, Steven said. A goal for this research is to determine a line within a breed that is genetically different with regard to tenderness and observe those differences over a five to 10 year period. Information like that could be used to improve selection strategies for bulls.
"It's not going to happen tomorrow, and the answer is not going to be that one gene will ensure that the beef will be tender, because there are so many other factors involved," Steven said.
Researchers must look at environment, nutrition and handling, in addition to genetics, to discover why and how there might be variation in tenderness among different animals, he said.
In addition to working together professionally, Steven and Elisabeth Lonergan are also married, and like other colleagues, they work to combine resources and collaborate on projects that interest them both.
"Our interests are complementary. For a lot of our projects, we take separate ends of the research and work to make it come together," Elisabeth said.
They met while in graduate school at Iowa State University, and after completing their doctorates, they applied for two open positions at Auburn University in 1995.
"We have mutual interests, both socially and professionally," Steven said. "I think we work together really well."
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News from:
Office of Ag Communications & Marketing
Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)
Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
by Anna M. Lee
December 18, 1997
