Extension News

Improving the Tenderness of Beef

4/28/2005

AMES, Iowa -- The tenderness of beef is an important quality characteristic to both consumers and producers. However, the beef industry hasn't adopted a practical method to produce consistently tender beef. If cattle feeders were able to produce beef that is consistently tender, they could potentially open up some very lucrative niche markets for their product. Researchers at Iowa State University (ISU) have discovered that feeding compounds like 25-hydoxy-vitamin D3 to feeder cattle shows promise as a way to improve tenderness. Although more research is needed, this research study looks at the optimal dosage and time of administration.

According to Elisabeth Huff-Lonergan, associate professor of animal science, "The concept behind this method was developed based on years of biochemical studies of beef muscle. These studies have shown that a calcium-activated protease called calpain is responsible for much of the tenderization of beef."

Lonergan explains that calpain acts by essentially 'disassembling' the complex structure of muscle and in so doing, makes the product more tender. Free calcium in the muscle is required by calpain to be active and to allow it carry out its tenderizing role. "Since vitamin D3 and some of its metabolites (including 25-hydroxyvitamin D3) can raise the plasma levels of calcium, it was hypothesized that feeding very high dosages of these compounds could ultimately increase the amount of calcium that is available in the muscle for calpain to carry out its tenderizing role," she says.

Results from the experiments show that increasing the dosage of 25-hydroxyvitamin D3 increases plasma calcium without raising concentrations of 25-hydroxyvitamin D3. This study is the first to look at key variables including the presence of antioxidants in the diet of beef cattle. Calpain can be inactivated if it is oxidized, thus the current study sought to examine the effect of combining high levels of 25-hydroxyvitamin D3 with high levels of the antioxidant vitamin E in the diet of the feedlot animals. In spite of this, the use of 25-hydroxyvitamin D3 is still a new concept, and more research needs to be done before it becomes a common practice.

For more information or to read the full report, visit the Iowa Beef Center's Web site at www.iowabeefcenter.org and click on the 2005 Beef Research Report link under Activities and Research, or call (515) 294-BEEF.

-30-

Contacts :
Elisabeth Huff-Lonergan, Iowa State University, (515) 294-9125, elonerga@iastate.edu
Rachel E. Martin, Iowa Beef Center, (515) 294-9124, remartin@iastate.edu
Suzanne Schuknecht, Iowa Beef Center, (515) 294-6780, suzannes@iastate.edu