Dean Pringle has two ways to get steaks leaner without sacrificing tenderness. Both are based on an enzyme system that regulates the muscle mass of beef cattle.
The calpain system, which is also in humans, tears down the proteins in muscle to allow new proteins to rebuild the muscle.
"All the time we're alive, our muscle mass is being degraded and rebuilt," said Pringle, an animal scientist with the University of Georgia College of Agricultural and Environmental Sciences.
To get that lean, tender steak, all you have to do is manipulate this enzyme system, he said.
Tender Fat
Meat with fat deposited within the steak is "marbled." It's tenderer than steaks with the fat in a layer around the outside. The less marbled, the tougher the steak.The calpain system remains active after death and continues to break down the protein in the muscle. That's why the beef industry ages meat after slaughter. The common practice increases flavor and tenderness.
Beef is aged in two ways: The dry way is to hang the meat in a temperature-regulated cooler with exposure to air. The wet way is to vacuum-package and refrigerate it in its juices for shipping.
Most meat sold in grocery stores has been aged three days to three months.
"Retail beef has more variation in aging time, depending on if the consumer is buying that product," he said. "If there's really high demand, the meat will be moved through the meat case faster and be aged for a shorter period of time."
Most restaurants, however, require at least 21 days of aging, some as high as 28 days or more, he said.
But even with the aging process, it's hard to maintain consistency in tenderness.
Calcium Fueled
The calpain enzyme system is fueled, so to speak, by calcium. The more calcium in the muscle, the more active this system becomes and the more degradation takes place and the more tender the meat.Pringle injected a calcium solution directly into the muscle of slaughtered cattle. This seems to work well in tenderizing the meat.
"Depending on the level of calcium, you can reach a 14-day aging point in 24 hours," he said. This can put tender meat into the marketplace faster.
You can also get that extra calcium into the meat by feeding cattle large doses of vitamin D a few days before slaughter, he said. Vitamin D helps release the calcium deposits in bones into the blood stream, which then go into the muscle and energize the enzyme system.
Tough Drawbacks
But there are drawbacks to each tenderizing method."The calcium injections can have some negative effect on flavor," he said. But adding beef flavor and salt to the injection can overcome the off flavor.
Also, the meat has to be labeled as having been injected with calcium. But this shouldn't be a problem. Many common consumer goods are "fortified with calcium." The injections are no different, he said.
The industry injects meat now with a mixture of salt and phosphate. This does tenderize it, but not as much as the calcium injections.
Large quantities of vitamin D can suppress cattle's appetites. Feedlot owners don't like this. The decreased feeding reduces the weight and available meat on the animal.
Marketing Edge
Pringle's research could help Southeastern cattle producers gain a marketing edge. The Brahman cattle breed is common in Southeastern herds. This breed can handle the heat, bugs and general Southeastern climate better than other beef cattle. But it's known to have tougher pieces of meat.These tenderizing techniques work in Brahman cattle and could help Southern producers who want to raise these cattle.
"We could get to the point where we're producing a Southeasten guaranteed-tender beef product that's more consistent and leaner,” he said.
