Graduate Student Research Poster Competition -- M.S. Division

Introduction of case-ready fresh meats to the marketplace has demonstrated a need to evaluate the benefits of this technology. The objectives of this study were to evaluate visual and chemical attributes of three different USDA quality grades (High Choice and above, Low Choice, Select) and three different muscles (semimembranosus, semitendinosus, and biceps femoris) of beef steaks encased in high-oxygen (80% O2/20% CO2) modified atmosphere packaging (MAP). Steaks from each treatment group (3 muscles, 3 grades, 2 packaging types) were displayed under retail conditions for 1, 3, 5, 7, and 10 d. Three steaks from each muscle-grade-package type combination were evaluated on each day by a five-member trained panel for visual color (lean color, discoloration, overall acceptability) and analyzed with a Minolta Chroma Meter CR-300 for L* a* b* values (lightness, redness, yellowness). Chemical analysis included percent metmyoglobin and lipid oxidation (TBARS). There were no grade x packaging interactions (P > 0.05) for lean color, discoloration, overall appearance, or L*, a* and b* values. However, the main effect of grades for these quality parameters was significant, with Low Choice and Select being higher than High Choice for L* values and Low Choice being more desirable than both High Choice and Select for lean color, discoloration, overall appearance, and a* and b* values. There were no grade x packaging interactions for percent metmyoglobin and TBARS values, however, grade had a main effect (P < 0.05) on percent metmyoglobin content, with High Choice being higher than both Low Choice and Select. TBARS values also differed (P < 0.05) among grades. These findings indicate quality grade has a major influence on color stability of high-oxygen packaged beef steaks. Regardless of muscle type and grade, however, whole muscle steaks from the round can achieve an extended shelf-life by use of novel MAP technology.