Synergic Effects of Light Salting, Vacuum Packaging, and Onion Extract on the Quality Retention of Refrigerated Rainbow Trout (Oncorhynchus mykiss) Fillets

Abstract

This experiment investigated the synergistic effects of vacuum packaging, light salting, and onion extract on the shelf life of rainbow trout (Oncorhynchus mykiss) fillets stored under refrigeration. The chemical, microbial, and organoleptic changes were monitored for up to 18 days in fillets. Total volatile basic nitrogen (TVB-N) and free fatty acid (FFA) values were evident in the order: control (without salting, vacuum packaging, and extract) > air packaged, salted (APS) > vacuum packaged, salted (VPS) > and vacuum packaged, salted, containing 2% and 4% (v/w) onion extract (2% and 4% VPSOE) throughout the storage period. Thiobarbituric acid values in APS groups were higher than control groups. Data from microbial assay showed that treatment with 2% and 4% VPSOE decreased total viable microbial count (TVC) compared with other treatments. APS, VPS, and VPSOE samples remained acceptable for up to 8, 12, and 15 days, respectively. The most suitable indices for determining shelf life of rainbow trout fillets are TVC.