Oxidative stability during frozen storage of fillets from silver catfish (Rhamdia quelen ) sedated with the essential oil of Aloysia triphylla during transport

Abstract

ABSTRACT: This research aimed to evaluate whether the essential oil of Aloysia triphylla (EOAT) used in vivo as a sedative in the water for transporting fish could increase the oxidative stability of silver catfish (Rhamdia quelen) fillets during frozen storage. The chemical composition of EOAT and of fillets from fish exposed to EOAT (0, 30 or 40µL L-1) were assessed. The pH and lipid oxidation parameters (conjugated dienes, CD; thiobarbituric acid-reactive-substances, TBARS) were evaluated in the fillets throughout the storage period (-18±2oC/17 months). The main compounds found in EOAT were α- and β-citral. Treatment with EOAT did not modify the proximate composition of the fillets, but 40µL L-1 EOAT reduced pH levels when compared to the control fillets (P<0.05). Compared to the control fillets, the fillets from fish treated with 30 and 40µL L-1 EOAT had higher initial CD values (P<0.05), whereas fillets from fish treated with 40µL L-1 EOAT had lower TBARS levels after 6, 9 and 17 months of storage (P<0.05). Results indicated that use of EOAT as a sedative in silver catfish transport water delays the degradation of primary oxidation products (CD) into secondary products (TBARS) in the frozen fillets. This delay in the lipid oxidation rate may increase the shelf life of frozen fillets.