| Abstract
| - High-pressure processing is a nonthermal technique ensuring food product safety and enabling alonger shelf life. The purpose of this experiment was to evaluate the effect of high pressure on themain proteolytic enzymes involved in fish muscle degradation during storage. Enzymes were extractedwith sarcoplasmic proteins from Dicentrarchus labrax sea bass white muscle. Activity of cathepsinsB, D, H, and L was quantified in protein extract, whereas calpain activity was evaluated after isolationfrom its endogenous inhibitor. High-pressure processing up to 500 MPa enhanced the activity ofcathepsin B, H, and L, whereas the activity of cathepsin D increased up to 300 MPa and decreasedabove 300 MPa. With regard to calpain activity, high-pressure processing led to a decrease of activity,which was zero above 400 MPa. We suggest a leading explanation based on simultaneousdeactivation of enzymes and an increase of liberation from lysosomes for cathepsins and ondissociation of subunits for calpains. Keywords: High pressure; fish; protease; calpains; cathepsins
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