Comparative Study on the Effect of Cold Atmospheric Plasma, Ozonation, Pulsed Electromagnetic Fields and High-Pressure Technologies on Sea Bream Fillet Quality Indices and Shelf Life

Abstract

A comparative study on the effect of nonthermal processing using cold atmospheric plasma (CAP), ozonation (OZ), pulsed electromagnetic fields (PEMF) and high pressure (HP) on the quality and shelf life of fresh sea bream fillets was conducted. The aim was the selection of the optimum nonthermal processing technology for minimum effect on the fish quality and maximum shelf-life extension, based on pre-selected processing conditions for each technology. Air plasma was generated using a surface dielectric barrier discharge (SDBD) source (3 kV, 45 kHz) applied for 15 min at 25 °C. PEMF (80 J/pulsed energy, 12.5 mT, 3 Hz) and OZ (1.3 mM of aqueous ozone, flow rate 640 ppm) were also applied for 15 min at 25 °C. HP treatment at 300 MPa/5 min at 25 °C was studied. Processed and unprocessed fillets were stored at 4 °C for 22 days. The fish fillets were analysed for their microbial load, pH, texture, colour, lipid oxidation, and sensorial characteristics, during storage. The shelf life of the product was extended by 4 and 2.5 days after HP and CAP processing, respectively. HP was more effective on the microbial load reduction compared to the other processes; nevertheless, colour and texture alteration of the fish fillets was observed. CAP processing decreased the initial total microbial load by 1.03 logCFU/g, while also resulted to reduced intension of the fish odour. PEMF and OZ affected slightly the quality indices nevertheless found to be less effective on the microbial load reduction with only 1 day shelf-life extension of the fillets.