Abstract
The objective was to determine the effects of modified atmosphere packaging (MAP) on the surface color of dark-cutting beef that had been aged for 21 d. The USDA Choice (normal-pH; IMPS #180) strip loins (n = 10) and no-roll dark-cutter strip loins (n = 10) were obtained from a commercial packing plant within 72 h of harvest. Both normal-pH and dark-cutting beef were vacuum packaged and aged for 21 d. Steaks were cut from both normal and dark-cutting loins, assigned to 1 of 3 packaging treatments; PVC, HiOx-MAP, and CO-MAP, and stored in a simulated retail display under continuous fluorescent lighting at 2°C for 6 d. Instrumental and visual color were measured every 24 h. Thiobarbituric acid assay was used as an indicator for lipid oxidation. There was a packaging × muscle type × display time interaction (P < 0.0001) for instrumental and visual color. On d 1 of display, dark-cutting steaks packaged in HiOx-MAP had greater (P < 0.001) a* values and chroma than dark-cutting PVC steaks. On d 6 of the display, dark-cutting steaks packaged in CO-MAP had 10 units greater a* values than dark-cutting steaks packaged in PVC. The visual panel also noted less muscle darkening (P < 0.002) in HiOx-MAP and CO-MAP compared with steaks packaged in PVC on d 6 of the display. There was less surface discoloration (P < 0.001) in HiOx-MAP and CO-MAP dark-cutting steaks compared with PVC dark-cutting steaks by the end of the display. There was a packaging × muscle type interaction for instrumental L* values and lipid oxidation. Dark-cutting steaks packaged in HiOx-MAP and CO-MAP had greater (P < 0.05) L* values compared with dark-cutting steaks in PVC packaging. In conclusion, HiOx-MAP improved redness of dark-cutting beef during the initial phase of display, while CO-MAP resulted in a stable red color.
Highlights
Failure to have a characteristic bright-red color at the cut surface of the ribeye muscle during grading results in discounted carcass value
Increased aging time coupled with high oxygen levels in normal-pH conditions can promote lipid oxidation and decrease metmyoglobin reducing activity, leading to lower color stability in normal-pH steaks packaged in HiOxMAP (English et al, 2016b)
Surface color of dark-cutting beef color that had been aged for 21 d was improved with the use of HiOx- and CO-modified atmosphere packaging (MAP)
Summary
Failure to have a characteristic bright-red color at the cut surface of the ribeye muscle during grading results in discounted carcass value. The 2011 National Beef Quality Audit reported that 3% of carcasses sampled were graded as dark-cutters (Moore et al, 2012). Dark-cutting beef is an effect of a metabolic condition(s) due to chronic stress resulting in limited lactic acid formation in post-rigor muscles. Elevated muscle pH can enhance mitochondrial activity and deoxymyoglobin formation (Ashmore et al, 1971; Ashmore et al, 1972; Egbert and Cornforth, 1986; Tang et al, 2005; Mancini and Ramanathan, 2014; English et al, 2016a). Developing strategies to improve redness is essential to maximize the value of beef
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