Effect of electrohydraulic shockwave treatment on tenderness, muscle cathepsin and peptidase activities and microstructure of beef loin steaks from Holstein young bulls

•Meat tenderness is a problem in the meat industry with important economical repercussion.•Electrohydraulic generated shockwaves is an effective method to tenderize beef steaks.•Cathepsin and peptidases activities are not affected by shockwave treatment.•Physical disruption on the microstructure seems to be responsible for the improved tenderness.

Hydrodynamic pressure processing (HDP) or shockwave treatment improved tenderness (18% reduction in Warner–Bratzler shear force (WBSF) of beef loin steaks. Endogenous muscle proteolyic activities (cathepsins and peptidases) and protein fragmentation of sarcoplasmic and myofibrillar proteins detected by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) were not influenced by HDP. However, microstructure changes were clearly detected using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Specifically a disruption of the structure at the muscle fiber bundles and an increased endomysium space were observed. The present paper supports the evidence of physical disruption of the muscle fibers as a cause behind the tenderness improvement. The paper discusses the possible mechanisms responsible for the meat tenderisation induced by HDP treatment.