Kinetic modelling of texture and colour changes in frozen fish: effect of high pressure processing as a pre-freezing treatment

Abstract

High pressure processing (HPP) is a promising technology for improving food safety and extending shelf life. This study examined the effects of HPP (150 MPa, 2 min) followed by frozen storage at −10, −18, or −30 °C on the texture and colour of European hake (Merluccius merluccius) over 12 months. Texture parameters (toughness and firmness) were assessed in raw and cooked samples, along with instrumental colour (L∗, a∗, b∗). Results showed that storage time generally increased toughness and firmness, though this trend stabilized or reversed after 6 months. Lower storage temperatures, particularly −30 °C, better preserved textural properties. HPP-treated fish showed higher initial toughness and firmness, suggesting enhanced structural integrity and improved texture retention during storage. Colour stability was also greater in HPP-treated samples, with reduced discoloration and better maintenance of lightness (L∗) over time. Overall, combining HPP with storage at −18 or −30 °C effectively preserves both the structural and visual quality of frozen hake, offering a promising strategy for shelf-life extension.