Postmortem aging is well known to improve eating quality characteristics, such as tenderness, juiciness and flavor; however, extended aging periods have been demonstrated to lower oxidative stability of beef muscles, resulting in discoloration and possible rancidity. This is problematic, as consumers consider surface color of fresh meat products as an indicator of wholesomeness and freshness when making their purchasing decisions. In general, consumers begin to reject beef products when surface metmyoglobin (the oxidized form of myoglobin responsible for brown discoloration) levels reach a threshold of 20 percent. Therefore, developing mitigating systems to minimize rapid discoloration during display is crucial to reduce food waste and economic losses.
One of the well-known on-farm strategies to improve oxidative stability of fresh meat is to feed the animals with antioxidative feedstuffs, such as vitamin E. Recently, researchers from Purdue University evaluated the efficacy of supplementing ruminal bypass arginine (ARG) and lysine (LYS) to improve performance of beef steers, as well as oxidative stability of aged beef loins. ARG has been shown to have a multitude of roles in the body, such as enhancing immune function, regulating protein synthesis and mitigating the stress response. In pork, ARG supplementation was shown to improve intramuscular fat content and lower drip loss, the latter being attributed to improved antioxidative status of the muscle tissue. But no previous studies have evaluated the effects of ruminal bypass ARG supplementation on meat quality attributes and oxidative stability of aged beef loins. Dr. Brad Kim’s Meat Science and Muscle Biology group at Purdue University hypothesized supplementation of ARG may mitigate negative effects of extended aging storage on oxidative stability.