Summary
The effect of pulsed electric field (PEF) on the quality of beef loins (1 day post-mortem) and topsides (1 and 3 day post-mortem) was investigated using a range of treatment intensities.
The investigated parameters reported here are purge loss, cooking loss and meat tenderness (shear force) to identify the optimum PEF treatment conditions for each muscle that will be used subsequently for investigating colour and lipid stabilities. The tenderness of the loin samples was found to benefit from PEF treatment (19.5% reduction in the shear force) regardless the electrical input whereas the level of tenderness of the topsides was increased by increasing the treatment frequency (4.1, 10.4 and 19.1% reduction in the shear force at 20, 50 and 90 Hz, respectively).
Higher purge loss (%) and lower cooking loss (%) were found in PEF treated samples, but the total losses were similar. It is interesting to observe that the level of SM tenderness improvement was not dependent on the meat post-mortem time which will allows the use of PEF technology without any post-mortem time constraints up until 3 days post-mortem.
The effect of repeat PEF treatment (0, 1, 2 and 3 repeats) under optimal conditions (20µs, 10kV, 90 Hz) on the quality of beef loins and topsides (1 day post-mortem) was investigated. Also, the effect of the meat’s pH and fibre direction on the quality of PEF treated beef loins was studied. The investigated parameters were purge loss, cooking loss, meat tenderness (shear force) and colour and lipid stabilities.
The tenderness of the loin samples was found to benefit from repeated PEF treatment (on average a 2.5 N reduction in the shear force for every extra PEF treatment). The purge loss of the topsides was significantly (P = 0.036) increased by PEF regardless the number of repetitions. Higher cooking loss (%) was found in repeat PEF treated loins, but not the topsides. The redness of the loins and topsides decreased and the hue angle was increased by increasing the PEF repeat treatment. No effect of pH and fibre direction on PEF was found.
Further, the effect of PEF on the quality of hot-boned beef loins (Longissimus lumborum, LL) and topsides (M. Semimembranosus, SM) was investigated using a range of treatment intensities (20 µs; voltage = 5 and 10 kV; and frequency = 20, 50 and 90 Hz). Also, the effect of repeat PEF treatment (0, 1, 2 and 3 repeats) under optimal conditions (20µs, 10kV, 90 Hz) on the quality of hot-boned beef loins and topsides was investigated. The investigated parameters reported here are purge loss, cooking loss, changes in pH and conductivity, and shear force to identify the optimum PEF treatment conditions for each muscle.
The tenderness of the hot-boned SM samples was found to benefit from PEF treatment (21.6% reduction in the shear force) regardless of the electrical inputs, whereas the shear force level of the LL tended to increase by increasing the treatment frequency. Treated LL muscles tended (P = 0.08) to have a higher cooking loss (%) compared with non-treated control (a 1.5% increase in cooking loss (%) was found in treated LL muscles compared with non-treated control), but no effect was found on purge loss (%). Opposite effects were found in SM where within the PEF treated samples there was a tendency toward decreased cooking loss as a result of ageing (P = 0.08) and significantly higher purge losses (P = 0.023) in PEF treated samples regardless the intensity of treatment.
