Packaging atmospheres and injection enhancement affect beef tenderness and sensory traits

Case-ready meat provides many benefits, including quality and safety. Meat packaged in high-oxygen (HiO2) modified atmosphere packaging (MAP) has a desirable bright red display color but may have increased off- flavors and decreased tenderness. According to several international research reports, steaks aged and packaged in HiO2 MAP had more off-flavor, including warmed-over flavor, and were less tender and juicy than steaks aged in vacuum packaging (VP). Research at Kansas State University found that injection-enhanced beef quadriceps muscles packaged in HiO2 MAP were less tender and had more offflavors than those in ultra-low oxygen MAP. Detrimental effects of O2 on tenderness might be caused by protein oxidation. Oxidation of beef muscle proteins early postmortem inactivates the primary enzyme (μ-calpain) necessary to break down proteins postmortem, which results in decreased myofibrillar proteolysis and limited tenderization. Injection-enhancement improves tenderness and juiciness while decreasing variation and often is used in conjunction with MAP. Several studies have reported that enhanced steaks were more tender and juicy than non-enhanced steaks. Several researchers found an increase in beef flavor associated with enhanced steaks, but others have reported a decreased or no change in beef flavor. Offflavors associated with enhanced beef include salty and oxidative. Objectives of our study were to determine the effects of packaging atmosphere and injection-enhancement on beef strip loin, eye of round, and chuck clod tenderness, sensory traits, and desmin degradation