Effects of ultrasonic processing on caspase-3, calpain expression and myofibrillar structure of chicken during post-mortem ageing

In this investigation, ultrasonic treatments at a frequency of 40 kHz and power of 1500 W made caspase-3 and calpain activities significantly higher in chicken muscle after slaughter during 5 d storage (p < 0.01). Additionally Western blotting analysis of α-spectrin showed that ultrasonic treatments caused the production of α-spectrin degradation products of 120 and 150 kDa more dense than the control (p < 0.01). Degradation of calpastatin during chicken meat ageing was induced by ultrasound treatments (p < 0.01), which suggested the ability of caspase-3 to cleave calpastatin. SDS-PAGE showed that all treatments enhanced accumulation of the 30 kDa troponin-T degradation product (p < 0.01), and transmission electron microscopy images of myofibrils displayed that damage of ultrasound treatment for 60 min was more extensive than at 30 min. The findings proved the low-frequency and high power ultrasonic treatments improved disruption of myofibrillar structures and increased proteolysis of chicken meat faster by triggering an apoptosis cascade.