Environment big factor in creating tough steak

Genetics plays role | Some breeds are more consistently tender

Genetic tests can predict whether a beef animal might produce tender meat, but many other factors also affect quality.

“Sixty percent of the variation in tenderness is not due to genetics. It is due to environment,” said geneticist Steve Miller of the University of Guelph.

“You could have the best genetics for tenderness but if the animal was mistreated or the carcass was not handled properly, then you can come up with a tough steak,” he said in an interview at a conference discussing genomics for the beef industry.

Beef Innovations, which the Canadian Simmental Association sponsored July 15-16 in Calgary, looked at how genomics can improve cattle. The accuracy of genomic predictions is improving, but further refinement is needed.

However, scientists at the conference said genomics can help producers increase the value of their cattle when combined with other information such as expected progeny differences, which is data gathered on a sire’s offspring.

“We need to keep in mind we are all in the food production business. Our ultimate goal is producing a product for consumers,” said meat scientist Mike Dikeman, a professor emeritus at Kansas State University.

Beef is often tested using the Warner Bratzler shear force test, which measures the pounds of force needed to cut through a small core of cooked meat. It is not easy to obtain these measurements on a commercial basis.

For example, it takes 8.4 pounds of force to cut through an AA graded sample and 6.6 lb. to go through Canadian Prime.

“In my opinion, a shear value of eight or less is still very acceptable,” said Dikeman.

Proper aging is another proven method to improve beef.

Toughness declines when beef is aged for seven days and nearly disappears if it is aged 21 days.

“Aging is great, but aging costs money,” Miller said.

Finding a way to make meat tender with less aging would save the industry money because meat wouldn’t have to sit in storage for as long.

The degree of proteolysis during aging in beef from young well-fed cattle is probably the most important factor that affects tenderness. Proteolysis is the breakdown of proteins after death, but the change is inhibited if the body contains high levels of calpastatin.

“The primary reason that Brahman cattle have less tender meat than bos taurus cattle is because they have higher levels of calpastatin,” Dikeman said.

Some breeds are marketed as producing tender beef, but Dikeman said researchers have found considerable variation among all cattle.

One study in the United States collected rib eye steaks from more than 7,000 progeny in 14 breeds. DNA samples were also collected for later discovery of gene markers.

The steaks were evaluated for tenderness using shear force instruments as well as trained taste testers. The result was a wide variance in tenderness, although some breeds were more consistently tender.

Marbling was also noted because grading systems in Canada and the United States include it is as a quality specification.

Marbling may account for 10 to 20 percent in the variation in tenderness. The fat creates a lubrication effect as it melts during cooking.

“Marbling does provide a bit of an insurance factor when product is cooked to a higher degree of doneness,” Dikeman said.

However, the reality is that calves are sold by hide colour and weight at auction markets, and there is no opportunity for a tenderness premium.

Dikeman said Canada could use its identification system to track tenderness in carcasses.

A DNA sample could eventually be collected from every calf and information attached to the electronic ear tag, he added.

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