Influence of vacuum-aging period on bloom development of the beef gluteus medius from top sirloin butts

The gluteus medius (GM) from USDA Select beef carcasses was used to test the effect of aging period on bloom development. Top sirloin butts (IMPS #184) were randomly allocated to 0, 7, 14, 21, 28, and 35 d vacuum-aging at 2 °C (n = 10/aging period). Each week, aged top sirloin butts were faced before two 2.5-cm-thick, non-adjacent steaks were cut and instrumental color (L∗, a∗, and b∗) of the GM was measured at 10-min intervals for 2 h after cutting. Steaks aged for 7 and 14 d were a more vivid (greater chroma values; P < 0.05), redder (greater a∗ values; P < 0.05), and more yellow (greater b∗ values; P < 0.05) color than steaks from the other aging periods. Change in total color (ΔE) was greater (P < 0.05) for steaks from top sirloin butts aged 7, 14, and 21 d than steaks from top butts aged 28 and 35 d, whereas oxymyoglobin percentages for steaks from top butts aged 7 and 14 days were greater (P < 0.05) than those from top sirloin butts aged 28 and 35 d. As much as 90% of the total increase (P < 0.05) in a∗, b∗, and chroma values, as well as hue angles and oxymyoglobin percentages, was achieved during the first 60 min after cutting.