No abstract

The objective was to evaluate the effects of high-pressure processing (HPP) levels on retail color of dark-cutting beef. Eight USDA Choice (mean pH=5.5; normal-pH beef) and 12 dark-cutting (mean pH=6.3) strip loins were obtained from a commercial packing plant within 2 d of harvest. Dark-cutting loins were cut into equal sections, vacuum packaged,and randomly assigned to 0 (no HPP), 300, 450, and 600 MPa of pressure for 90 s using chilled water. Following 48 h of dark storage at 2°C, dark-cutting loin sections were cut into 1.9-cm-thick steaks, placed in Styrofoam trays overwrapped in polyvinyl chloride (PVC) film, and placed in a simulated retail display for 8 d. The surface color readings were measured every 24 h using a HunterLab MiniScan XE Plus spectrophotometer, whereas a trained color panel (n=6) evaluated dis-coloration, paleness, and lean color on steaks. Lipid oxidation was evaluated on day 0, 4, and 8 of retail display, and structural changes were determined using light microscopy on day 0 of display. There was a significant HPP level×day of retail display interaction for all instrumental color measurements. Throughout the retail display, L* values of 450 and 600 MPa applied steaks were greater (P<0.05) than 300 MPa and controls. There was a significant pressure level×day of retail display interaction when panelists evaluated lean color and discoloration. Steaks treated at 300 MPa exhibited brighter red color and lower (P=0.0023) thiobarbituric acid reactive substance values than other pressure levels and normal-pH control steaks. Light microscopy analysis indicated that HPP increased space between muscle structures. In conclusion, low (300 MPa) and moderate (450 MPa) pressure levels can improve redness of dark-cutting steaks.

Consumers often use meat color to determine doneness. A greater than normal pH of dark-cutting (DC) beef leads to less myoglobin denaturation, resulting in a persistent pink color that negatively impacts the perception of consumers of the cooked beef degree of doneness. High-Pressure Processing (HPP) is a non-thermal pasteurization technology to extend shelf-life. High pressure leads to denaturation of proteins and structural changes. There has been limited research and application utilizing HPP on fresh meat due to the pale color caused by HPP. The objective of the study was to evaluate different HPP levels on cooked steak color and sensory attributes of dark-cutting beef. Eight USDA Choice (mean pH = 5.5) and twelve DC (mean pH = 6.3) strip loins were obtained from a commercial packing plant within 1 d of harvest. Loins were cut into equal sections, vacuum packaged, and assigned HPP levels of 0 (no HPP), 300, 450, and 600 MPa with a holding time of 90 s. Following 48 hours of dark storage, loin sections were cut into 1.9 cm thick steaks, vacuum packaged, and randomly assigned to external cooked color, Warner-Braztler shear force (WBSF), and trained sensory panel. Steaks were cooked and then tempered to 71ºC. A trained sensory panel (n = 6) evaluated initial juiciness, sustained juiciness, tenderness, beef flavor intensity, and overall acceptability. The data were analyzed using the Glimmix Procedure of SAS. HPP treatment did not (P > 0.05) affect initial juiciness, sustained juiciness, beef flavor intensity, or overall acceptability. However, 600 MPa made DC steaks tougher and lighter in appearance (P < 0.05) than all other treatments. HPP treatments did not affect the a* and chroma of the external cooked color. In conclusion, low (300 MPa) and moderate (450 MPa) pressure levels did not have a negative impact on cooked steaks.