Lactiplantibacillus plantarum postbiotics and thyme essential oil nanoemulsion-based edible spray: An innovative approach to extending shelf life of rainbow trout fillets

Abstract

This study aimed to investigate the effects of postbiotics from Lactiplantibacillus plantarum (PL) and Thymus daenensis Celak essential oil (TDEO) nanoemulsion (EON) on the microbial, chemical, and sensorial characteristics of rainbow trout fillets. PL50 (50% w/v of PL), EON1.5 (1.5% v/v TDEO), EON3 (3% v/v TDEO), and PL50-EON (combined forms of PL50 and EON at two concentrations) were applied as treatments. Total psychrotrophic count (TPC), total mesophilic count (TMC), pH, total volatile base nitrogen (TVB-N), thiobarbituric acid (TBA), and sensorial characteristics of the control and treatment groups were evaluated during nine days of storage at 4 degrees C. The shelf life of control sample was up to 6 days, while on the same day, PL50-EON3 exhibited significantly lower TPC (2.59 log10 CFU/g), TMC (4.87 log10 CFU/g), and TVB-N value (23.40 mg/100 g). Sensory evaluation showed that sample with PL50-EON3 had higher acceptance than the control. Principal component analysis revealed that EON3 and PL50-EON3 had positive effects on the quality parameters of the fillets. In conclusion, PL50-EON prolonged the shelf life of fillets by more than 3 days based on microbial, chemical, and sensorial threshold limits. These findings demonstrate the potential of PL and TDEO to develop a preservative solution for fish.