The effect of essential oil of Zataria multiflora incorporated chitosan (free form and Pickering emulsion) on microbial, chemical and sensory characteristics in salmon (Salmo trutta)

Abstract

The objective of current research was to prepare a new biodegradable coating containing chitosan (Ch) and zataria multiflora essential oil (ZMEO) (free and Pickering emulsion (PEO) forms), in order to enhance the Salmo trutta shelf life. Our results showed, the mean of films thickness, mechanical properties (elastic modulus (EM) and tensile strength (TS) analysis) and WVP in different treatments were ranged from 0.103 ± 0.003 (for Ch) to 0.109 ± 0.003 (for Ch-PEO (2.5 %)) µm for thickness, from 3.2 ± 1.6 (for Ch) to 8.15 ± 2.3 (for Ch-EO) MPa for EM, from 1.3 ± 0.5 (for Ch-EO) to 1.6 ± 0.06 (for Ch) Mpa for TS and from 0.1 ± 0.02 (for Ch) to 0.8 ± 0.05 (for Ch-EO) (×10 − 11(g m/m2 s Pa) for WVP. In current research, the lowest and highest total viable counts (TVC) was related to Ch-PEO (1.7 log CFU/g) and control treatments (4.65 log CFU/g). The lowest and highest of pH was related to the Ch-PEO (6.45) and the control (7.1), the lowest and highest of PV (peroxide value) was related to Ch-PEO (0.34 meq/kg) and control treatment (1.37 meq/kg), the lowest and highest of TBARS (thiobarbituric acid reactive substances) was related to Ch-PEO (0.37 mg/kg) and control treatment (2.23 mg/kg) and also the lowest and highest of TVB-N (total volatile base nitrogen) was related to Ch-PEO (17.7 mg) and control (59 mg). Also, Ch-PEO showed the best sensory properties after sixteen days. Among all the treatments in all the tests, the best maintenance property was related to the Ch-PEO, therefore, chitosan coatings containing ZM Pickering emulsion should be considered as a potential active coating in the fish industry.

Keywords

• Antimicrobial properties
• Antioxidant activity
• Fish
• Microbiological analysis
• Seafood