Effects of Modified Atmospheric Packaging on Ground Chicken Color and Lipid Oxidation

The objective of the current study was to evaluate the color changes and lipid oxidation of ground chicken patties packaged in polyvinyl chloride (PVC) film, high-oxygen (HiOx)–modified atmospheric packaging (MAP; 80% oxygen + 20% carbon dioxide [CO2]), and carbon monoxide (CO)-MAP (0.4% CO + 19.6% CO2 + 80% nitrogen) and stored at 2°C. Surface color was measured using a HunterLab MiniScan spectrophotometer on days 0, 1, 2, and 4. Lipid oxidation, pH, and aerobic plate count were determined on days 0 and 4 of storage. Fatty acid profiles were determined on day 0 to characterize saturated and unsaturated fatty acids. Patties packaged in PVC had greater (P < 0.05) pH than HiOx-MAP and CO-MAP. Gas chromatography analysis indicated that ground chicken has 72.8% unsaturated fatty acids and 27.2% saturated fatty acids (based on total lipids and fatty acid methyl ester). The formation of carboxymyoglobin on ground chicken patty surface was confirmed by peaks at 420 and 570 nm, whereas oxymyoglobin had peaks at 410 and 580 nm. Instrumental color analysis indicated both HiOx-MAP and CO-MAP had greater (P < 0.05) redness (a* values) than PVC on day 4 of storage. Patties packaged in HiOx-MAP had greater (P < 0.05) chroma values than CO-MAP and PVC on day 4 of storage. Visual panelists noted less (P < 0.05) surface discoloration in CO-MAP than PVC and HiOx-MAP on day 4 of storage. Lipid oxidation was greater (P < 0.05) in PVC and HiOx-MAP than CO-MAP. CO inclusion at 0.4% level effectively inhibited lipid oxidation and stabilized surface redness during refrigerated storage of ground chicken.

Effects of Rosemary and Green Tea Antioxidants on Ground Beef Patties in Traditional and Modified Atmosphere Packaging

The objective of this study was to analyze the effects of rosemary (RSM) and green tea (GT) added to groundbeef to extend shelf life. Four antioxidant treatments were used: control, 2,500 ppm RSM, 300 ppm GT, and 2,500 ppm RSM + 300 ppm GT (RSM + GT). Patties from each treatment (n = 42) were randomly packaged into one of 3 types: polyvinyl chloride (PVC) overwrap, modified atmospheric packaging (MAP), or master packages (MP). Packages of MAP and MP were flushed with 0.4% CO, 69.6% nitrogen (N2), and 30% carbon dioxide (CO2). Patties in PVC and MAP were placed directly into display cases for 7 d, and MP patties were placed in dark storage for 7 d and then in display cases for another 7 d. Instrumental and subjective color, lipid oxidation, and sensory panel scores were measured. In MAP, patties with GT had increased (P < 0.05) a* and chroma values by day 6 of retail display. In MP at 3 d of retail display, GT patties exhibited increased (P < 0.05) L* values (lighter), display color (deeper red), and surface discoloration (greater discoloration) scores compared with RSM + GT patties. However, GT and RSM patties were not different (P > 0.05) for these parameters. Trained sensory panelists did not detect a difference between control and GT patties for the green-hay attribute; however, RSM patties had highly detectable (P < 0.05) green-hay flavor. Panelists were unable to detect any differences (P > 0.05) for rancid or fatty flavors regardless of treatment. Patties in MAP were more color stable than those in PVC after 6 d of retail display. In conclusion, patties in MP with GT showed positive instrumental and objective color measurements, as well as lipid oxidation values after 3 d of display, combined with undetectable flavor, warranting further research.