Autolytic changes involving proteolytic enzymes on Atlantic salmon (Salmo salar) preserved by hyperbaric storage

Abstract

he effect of hyperbaric storage (HS, 50–75 MPa at 10–37 °C) on proteolytic enzymes and muscle proteins of Atlantic salmon (Salmo salar) was assessed and compared to atmospheric pressure (AP, 0.1 MPa) at the same storage temperature and refrigeration (AP, 5 °C). Generally, activities of acid phosphatase, cathepsin B and D, and calpains decreased when compared to fresh salmon, with a more’ pronounced effect of storage temperature of 37 °C in HS/AP samples. However, activity recovery was observed for some enzymes, as the case of cathepsins B and D, and calpains, whose showed an increase of residual activity for samples stored at 60 MPa/10 °C and 75 MPa/25 °C after 50 and 25 d, respectively. A pronounced increase of myofibrillar fragmentation index (MFI) was observed at 75 MPa (25/37 °C) after 10 d (3.2-/4.3-fold, respectively). Otherwise, at 60 MPa/10 °C, a decrease of MFI values was observed after 50 d of storage. For sarcoplasmic proteins, no effect was observed at 60 MPa/10 °C during 30 d of storage, with a slight increase after 50 d. At 75 MPa/25 °C, a decrease of sarcoplasmic proteins content (46%) was obtained after 10 d with no further changes during the 25 d of storage.