Effect of high-pressure pre-treatments on enzymatic activities of Atlantic mackerel (Scomber scombrus) during frozen storage

• High-pressure pre-treatments cause changes on enzyme activities during frozen storage of Atlantic mackerel.
• Acid phosphatase activity was only slightly reduced at 450 MPa.
• At 150 MPa, the activity of cathepsin B and lipase increased with pressure holding time.
• At 300 MPa, lipase activity decreased, and no effect was observed at 450 MPa.
• Cathepsin D activity increased at 150 and 300 MPa and with frozen storage time and decreased at 450 MPa.

In this work, we studied the effect of high-pressure processing (HPP) pre-treatments (150, 300 and 450 MPa for 0, 2.5 and 5 min) on key enzyme activities in Atlantic mackerel (Scomber scombrus) during frozen storage (3 months of accelerated storage, − 10 °C). Except for a minor decrease from treatment at 450 MPa, no substantial effect on acid phosphatase activity was observed. In contrast, cathepsins B and D and lipase were affected by HPP and frozen storage. Increasing the pressure reduced cathepsin B and lipase activities. Generally, increasing the holding time at 150 MPa increased the activity of cathepsin B and lipase (except at month 1), while increasing the holding time at 300 MPa reduced the lipase activity, and no effect was observed at 450 MPa. Overall, cathepsin D activity increased with frozen storage time and for treatments at 300 MPa but decreased at 450 MPa. This work provides novel information of HPP pre-treatments application, lowering enzyme activity during frozen storage of Atlantic mackerel.Industrial relevanceThe activity of fish endogenous enzymes has an important role in its deterioration during frozen storage, limiting its commercialisation. This research presents valuable information concerning the employment of high-pressure processing pre-treatments to reduce deteriorative enzymatic activities during the subsequent frozen storage of Atlantic mackerel (Scomber scombrus). High-pressure processing pre-treatments can so be of interest for fish processors to enhance the frozen storage of these fish species and possibly of others.