Repackaging Nitrite-embedded Dark-Cutting Steak in Aerobic Polyvinyl Chloride Film Decrease Surface Redness

Theoverall goal was to evaluate the effects of repackaging nitrite-embeddeddark-cutting steaks in polyvinyl chloride (PVC) film on surface color.Dark-cutting beef strip loins (n = 8; pH = 6.39) and USDA Low Choice beef striploins (normal-pH, n = 6) were selected at a commercial packing plant.Dark-cutting loins were bisected and randomly assigned to nonenhanceddark-cutting and enhanced dark-cutting with glucono delta-lactone and rosemarytreatments. Normal-pH and nonenhanced dark-cutting steaks were vacuum packaged (VP)and served as controls, while enhanced dark-cutting steaks were packed innitrite-embedded packaging (NP). Steaks from nonenhanced normal-pH in VP, non-enhanceddark-cutting-VP, and enhanced dark-cutting-NP loins were randomly assigned to3, 6, or 9 d of dark storage. Following dark storage, steaks were repackaged inPVC and displayed for 6 d. The instrumental color, visual color, and aerobicplate count were evaluated for all steaks.  Enhanced dark-cutting steaks in nitritepackaging increased (P < 0.05) a* values and nitric oxide myoglobincontent during 24 h of dark storage. Enhanced dark-cutting steaks packaged inNP had greater a* and L* values (P < 0.05) than nonenhanced dark-cutting-VP steaks during darkstorage. Upon repackaging the enhanced dark-cutting steaks from nitritepackaging, nitric oxide myoglobin decreased (P < 0.05) during the first 12 h of display. Loss of nitric oxidemyoglobin corresponds with a darker red appearance, increased surfacediscoloration, and decreased a*values. There were no differences (P> 0.05) in aerobic plate count between enhanced dark-cutting-NP and non-enhanceddark cutting VP steaks during 9 days of dark storage. In conclusion, NPimproved surface redness; however, repackaging enhanced dark-cutting from NP steaksin PVC decreased color stability and redness of dark-cutting beef. 

Environmental dust repelling from hydrophilic/hydrophobic surfaces under sonic excitations

Dust repelling from transparent polyvinyl chloride film surface via sonic excitation is examined and dynamics of repelled (inflight) dust particles are analyzed. An experimental rig is designed and built to assess the vibrational characteristics of the polyvinyl chloride film at different frequencies of sonic excitation. A high speed recording system and tracking program are utilized monitoring and evaluating the dynamics of the inflight particles. The dynamics of inflight particles are also simulated numerically and the predictions are compared with those of the experimental data. In order to examine the influence of dust particle adhesion on the dynamics of the inflight particles, the polyvinyl chloride film surface is hydrophobized through dip coating by functionalized nano-silica particles. Improvement of the optical transmittance of the dust mitigated film is determined via outdoor tests. The findings demonstrate that sonic excitation repels the particles from the film surface and it is more pronounced at 64 Hz excitation frequency while demonstrating that sonic excitation can be used for dust removal from transparent surfaces. The mitigation via sonic excitation improves the optical transmittance of the dusty surface by 77%, which becomes more apparent for hydrophobic surfaces.