Effects of aging on the fundamental color chemistry of dark-cutting beef

Abstract

The objective of the current study was to evaluate the effects of aging on myoglobin chemistry of dark-cutting beef. Ten USDA Choice (mean pH = 5.6; normal pH beef) and 10 no-roll dark cutter (mean pH = 6.4) strip loins were obtained from a commercial packing plant within 3 d of harvest. Loins were cut into 4 sections, vacuum packaged, randomly assigned to 0-, 21-, 42-, and 62-d aging at 2°C in the dark. Following aging, loin sections were cut into 2.5-cm-thick steaks and were used to determine bloom development, oxygen consumption (OC), metmyoglobin reducing activity (MRA), and lipid oxidation. Surface color readings were measured using a HunterLab Miniscan XE Plus spectrophotometer. A significant muscle type × aging time interaction resulted for OC ( < 0.001). Normal pH steaks declined more ( < 0.001) in OC during aging than dark-cutting beef. On d 0, dark-cutting beef had a greater OC ( < 0.001) than normal pH beef. There was a significant muscle type × oxygenation time × aging period interaction for L* values, deoxymyoglobin (DeoxyMb), and oxymyoglobin (OxyMb). When dark-cutting sections were aged for 62 d, both 0 and 60 min bloom development L* values were greater ( < 0.0001) than 0 min dark-cutting sections aged for 21 or 42 d. At all aging periods, normal pH beef had greater OxyMb content and lower DeoxyMb ( < 0.0001) during bloom development than dark-cutting beef. An aging period × muscle type interaction was significant for % overall reflectance ( = 0.0017) and absorbance ( = 0.0038). Dark cutting and normal pH beef loin sections aged for 62 d had greater reflectance ( < 0.0001) than 21 d. On d 0, dark-cutting beef had greater ( < 0.0001) MRA than normal pH beef. There were no significant ( = 0.14) differences in MRA between 42 and 62 d between dark-cutting and normal pH beef. Dark cutting steaks had lower thiobarbituric acid reactive substances values ( < 0.0001) than normal pH steaks. The results indicate that characterizing the myoglobin chemistry during aging will help to design strategies to improve appearance of high pH beef.

Modified Atmosphere Packaging Improves Surface Color of Dark-Cutting Beef

“…Previous research from our laboratory has indicated that blooming properties of dark-cutting steaks were improved with extended aging (English et al, 2016a). Greater myoglobin oxygenation, in part, can be due to decreased mitochondrial activity.…”

“…Dark-cutting beef has more myoglobin concentration than normal-pH beef (McKeith et al, 2016;English et al, 2016a). With a greater myoglobin concentration, one can speculate a bright-red color for dark-cutting steaks in CO-MAP than normal-pH steaks in CO-MAP.…”

“…A greater pH promotes muscle fibers to hold more water; therefore, less oxygen is diffused deep into the tissue (Lawrie, 1958;Offer and Trinick, 1983). Similarly, 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). Therefore, developing strategies to improve redness is essential to maximize the value of beef.…”

“…Further, a longer aging time can limit mitochondrial activity and alter muscle structure (Nishimura et al, 1998;Lenaz et al, 2002). We recently reported that extended aging of dark-cutting beef decreased muscle oxygen consumption and improved surface reflectance (English et al, 2016a). However, limited published research is currently available on the combined effects of modified atmosphere packaging and aging on surface color of dark-cutting beef.…”

High-oxygen modified atmosphere package improves color stability of <i>Longissimus lumborum</i> with high ultimate pH from pasture-fed Nellore bulls

“…Color stability studies in pH > 5.8 muscles are published mostly from Bos taurus beef (ABRIL et al, 2001;ENGLISH et al, 2016;MCKEITH et al, 2016). There is a lack of researches investigating Nellore beef with increased pHu.…”