A novel method to deliver natural antimicrobial coating materials to extend the shelf-life of European hake (Merluccius merluccius) fillets

Abstract

• Natural antimicrobial solutions of chitosan (CS), chitosan nanoparticles (CS NP), carnosolic acid nano-solubilisate were coated on hake fillets using an aerosolisation treatment method. • A combination of VSP and aerosolisation extended the shelf life of hake fillets. • Aerosolisation treatments can be used as additional hurdle technology. The objectives of this study were to investigate the effectiveness of aerosolisation as a novel method for coating natural antimicrobials solutions of chitosan (CS), chitosan nanoparticles (CS NP) and commercially available carnosolic acid nano-solubilisate (CASB) with a view to provide an additional hurdle to extend the shelf-life of vacuum skin packaging (VSP) European Hake ( Merluccius merluccius ) fillets. The aerosolisation of hake fillets with natural antimicrobial solutions of 0.1 % w/v CS, 0.1 % w/v CS NP, or 0.8 % w/v CASB extended significantly ( P < 0.05) the shelf-life of VSP hake fillets by up to 40, 50, and 55 %, respectively compared to untreated control samples. Moreover, the pH of hake fillets was significantly (P < 0.05) increased by CS and CS NP treatments compared to untreated control and CASB treatments. The colour parameters of treated hake fillets increased significantly throughout storage, independent of antimicrobial treatment for all samples. However, lightness was significantly ( P < 0.05) reduced by CASB treatments (compared to other treatments), redness was significantly ( P < 0.05) increased by CS NP treatments (compared to other treatments), and yellowness was significantly ( P < 0.05) increased with all CS, CS NP, and CASB treatments (compared to control samples). In addition, the whiteness index (WI) of hake fillets was reduced significantly ( P < 0.05) when aerosolised with CS, CS NP, and CASB treatments. The lipid oxidation (TBARS) of hake fillets, independent of the antimicrobial treatment, decreased significantly ( P < 0.05) throughout storage. The results from this study indicate that aerosolisation of natural antimicrobial materials can effectively extend the shelf-life of fish products.