Contributions of muscles of various color stabilities to the overall color stability of ground beef.

Ground high (HCS), intermediate (ICS), and low color stability (LCS) cow muscles were used to investigate effects of blending muscles of different color stabilities on ground beef display color. Six formulations at 90% and 80% lean points combining HCS, ICS, and LCS muscles were: 50% HCS + 50% ICS; 50% HCS + 50% LCS; 50% ICS + 50% LCS; 33.3% HCS + 33.3% ICS + 33.3% LCS; 75% HCS + 25% LCS; and 25% HCS + 75% LCS. Patties were packaged in a high oxygen (80% O(2), 20% CO(2)) modified atmosphere, held in dark storage for 5 d, then displayed for 4 d. The 80% lean patties containing >or= 50% HCS had the brightest red initial visual color. During display 75% HCS + 25% LCS at both lean points had the most cherry-red display color. Patties containing a greater proportion of HCS had greater metmyoglobin reducing ability throughout display. HCS, ICS, and LCS muscle can be mixed without adverse color affects, provided LCS muscle is or= 50% of the blend.

Prediction of Japanese color score.

Relationships between Japanese color score (JCS) and pork quality attributes were studied and three equations were developed to predict JCS. Averages for population one (n=781) traits were used to develop initial prediction equations and traits from population two (n=684) were used to evaluate the success of the prediction equations. The first equation was: JCS=12.698-(0.01128 x firmness)+(0.09008 x pH)-(0.00007199 x drip loss)-(0.266 x L*)+(0.06923 x a*)-(0.201 x b*)+(0.02143 x hue angle); r(2)=0.916. The second equation was: JCS=15.255-(0.259 x L*)-(0.213 x b*)+(0.02518 x hue angle); r(2)=0.931. The third equation was: JCS=12.920-(0.219 x L*)+(0.07342 x a*)-(0.02166 x b*); r(2)=0.906. All equations predicted 92% or more Japanese color scores within +/-0.50. Requiring fewer measurements, the second and third equations would be advantageous when sorting pork on the basis of JCS.

Cow biological type affects ground beef colour stability.

To determine the effects of cow biological type on colour stability of ground beef, M. semimembranosus from beef-type (BSM) and dairy-type (DSM) cows was obtained 5d postmortem. Three blends (100% BSM, 50% BSM+50% DSM, 100% DSM) were adjusted to 90% and 80% lean points using either young beef trim (YBT) or beef cow trim (BCT), then packaged in high oxygen (High-O(2); 80% O(2)) modified atmosphere (MAP). The BSM+YBT patties had the brightest colour initially, but discoloured rapidly. Although DSM+BCT patties had the darkest colour initially, they discoloured least during display. Metmyoglobin reducing ability of ground DSM was up to fivefold greater than ground BSM, and TBARS values of BSM was twofold greater than DSM by the end of display (4d). Though initially darker than beef cow lean, dairy cow lean has a longer display colour life and may be advantageous to retailers using High-O(2) MAP.