Effect of Selection for Reduced Residual Feed Intake on Pork Carcass Composition and Fresh Pork Quality

Selection for reduced residual feed intake (RFI) resulted in leaner carcasses and less intramuscular lipid in the pork loin. However, the selection approach did not result in differences in water holding capacity and color of fresh pork loin chops. Selection for reduced RFI has the potential to improve carcass composition with few detrimental effects on meat quality

Proteolysis Influences Tenderness of Aged Pork Loins

Aged pork loins were selected to have similar ultimate pH, color, lipid content, and purge. The star probe values (kg) obtained from these loins were evaluated and loins were sorted into either a low star probe (LSP) group or a high star probe (HSP) group. Loins were evaluated for autolysis of calpain-1 and degradation of troponin-T, desmin, and titin. Results showed calpain-1 was completely autolyzed in all samples. LSP pork loins exhibited more degradation of troponin-T, desmin, and titin, demonstrating proteolysis influences measured tenderness in aged pork

Effects of selection for decreased residual feed intake on composition and quality of fresh pork

The objectives of this study were to determine the extent to which selection for decreased residual feed intake (RFI) affects pork composition and quality. Pigs from the fifth generation of selection for decreased RFI (select) and a randomly selected line (control) were utilized. Two experiments were conducted. In Exp. 1, barrows (22.6 ± 3.9 kg) from select and control lines were paired based on age and BW. The test was conducted in 8 replicates of pairs for the test period of 6 wk. Calpastatin activity and myosin isoforms profile were determined on samples from the LM. Control barrows were heavier (59.1 vs. 55.0 kg; P \u3c 0.01) at the end of the test period. Calpastatin activity was greater (P \u3c 0.01) in LM of select barrows than control barrows. In Exp. 2, composition and quality of gilts (114 kg) from control and select lines were determined. The model included fixed effects of line, slaughter date, melanocortin-4 receptor (MC4R) genotype, barn group, line × slaughter date, genotype × line interactions, a covariate of off-test BW, and sire, pen, and litter fitted as random effects. The select line (n = 80) had 0.043 kg less (P \u3c 0.05) RFI per day than the control line (n = 89). Loin quality and composition were determined at 2 d postmortem. Desmin degradation was measured at 2 and 7 d postmortem. Purge, cook loss, sensory traits, and star probe texture were measured at 7 to 10 d postmortem on cooked chops. Residual correlations between RFI and composition and quality traits were calculated. Compared with the control line, carcasses from the select line tended to have less (P = 0.09) backfat, greater (P \u3c 0.05) loin depth, and greater (P \u3c 0.05) fat free lean. Loin chops from the select line had less (P\u3c 0.01) intramuscular lipid content than loin chops from control line. Significant residual correlations between RFI and both tenderness (r = 0.24, P \u3c 0.01) and star probe (r = −0.26, P \u3c 0.01) were identified. Selection for decreased RFI has the potential to improve carcass composition with few effects on pH and water-holding capacity. However, decreased RFI could negatively affect tenderness and texture because of decreased lipid content and decreased postmortem protein degradation

High Oxygen Packaging System Negatively Affects Color Stability and Sensory Attributes of Beef Cuts

Beef steaks stored in high-oxygen modified atmosphere packaging (HiOx-MAP) had more discoloration, lipid oxidation, and lower tenderness, juiciness, and flavor during 9 days display compared to the steaks packaged in vacuum (VAC). Therefore, MAP systems with lower oxygen mixture or incorporation of antioxidants through injection enhancement to meat in HiOx-MAP are recommended to minimize oxidation-induced quality deteriorations of beef round muscles