story to find out more.
Tommy Wheeler (left) and Stephen Shackleford (middle) prepare muscle for
calpain extraction as physiologist Mohammad Koohmaraie separates calpain and
calpastatin from a meat extract. Click the image for more information about
The Science Behind Making Steak More Tender
Elstein February 3, 2005
Consistently tender steaks may be more readily available at
restaurants and supermarkets in the future, thanks to technology developed by
Agricultural Research Service (ARS)
scientists in Nebraska and used by beef processors.
At the ARS
L. Hruska U.S. Meat Animal Research Center in Clay Center, Neb., animal
Koohmaraie is leading a group of researchers in determining how to make
steaks more tender. Some of their discoveries are already being used by
The scientists noticed meat is tender after slaughter, then toughens
before starting to become tender again. Accordingly, the scientists believe
steaks shouldn't be sold before they've aged for 14 days, to make sure the meat
has undergone maximum tenderization. A majority of beef processors are already
following this procedure.
They also discovered the enzyme µ-calpaina and the variation of
the protein called calpastatin, both of which have a major impact on meat
tenderness. Calpastatin determines how much calpain is active and how tender
the steak will be. Since calpain requires calcium for activity, the team has
developed a process for injecting calcium into meat in order to make it tender.
The scientists are also studying cattle genetics. Under the leadership
Smith, they are comparing the sequences of genes that produce calpain in
both tender and tough cattle. They have released a DNA test that accurately
identifies which cattle will likely provide tender steaks, so producers can use
those animals for breeding.
about the research in the February 2005 issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.