Essential oil from Dracocephalum kotschyi Boiss, antibacterial and antioxidant activities and natural preservative effect in shelf life extension of shrimp storage

Essential oil from Dracocephalum kotschyi Boiss, antibacterial and antioxidant activities and natural preservative effect in shelf life extension of shrimp storage
Parisa Akbari,¹ Arezoo Dastpak,^2,* Mozhgan Emtiazjoo,³
1. Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran
2. Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran
3. Department of Marine Biology, Faculty of Marine Sciences and Technology, Islamic Azad University, North Tehran Branch, Tehran, Iran
Introduction: The safety and shelf-life of food are some of the most challenging factors which food industries are currently confronted with. Several food preservation systems such as freezing, salting, and heating as well as more complicated methods like chemical and synthetic preservation and modified atmosphere packaging can be used to reduce the risk of outbreaks of food poisoning and improve the shelf-life extension of food. In recent years, the use of natural preservation methods is a field of growing interest. Essential oils (EOs) have achieved attention due to their food preservation effects, particularly for the antimicrobial and antioxidant effects. Plant essential oils contain large amounts of bioactive compounds. The antimicrobial properties of EOs are attributed to actions including their ability to disrupt cell wall and cytoplasmic membrane. The antioxidant activity of EOs is due to their potential ability to cease or suspend the oxidation reaction of organic materials in the presence of oxygen which is a result of some special components including phenols. This study was designed to evaluate the antioxidant and antibacterial, and effects of Dracocephalum kotschyi essential oil (EODK) in raw shrimp over a 7 day storage period at 4 °C.
Methods: : The hydrodistillation process was used for essential oil extraction. The yield of the oil was 0.1% and the oil was yellow. Shrimp meat was treated into different concentrations of EODK and the properties were compared to shrimp meat without any additive. Also, the chemical composition of the oil was analyzed using Gas chromatography, and the antioxidant and antimicrobial activities of EDOK were investigated.
Results: Several compounds have been identified in the essential oil. The major components found in the EODK were Limonene, α-terpineol, Caryophyllene, and perillyl alcohol. The essential oil’s IC50 value of 32.35 μg/ml in the DPPH assay, could be regarded as its strong antioxidant potential. Antibacterial activities of EODK were screening against five strains, Staphylococcus aureus, Escherichia coli, Shewanella putrifaciens, pseudomonas fluorescens, and Yersinia enterocolitica by minimum inhibitory and bactericidal concentration (MIC and MBC) and disc diffusion methods. The results indicated that EODK has the highest activity against Staphylococcus aureus and Escherichia coli at the concentration of 500 mg/ml. Finally, the EODK applications as food preservatives were studied. Indeed, the effect of different percentages (0.5, 1%) of EODK for microbiological (total viable count), physicochemical parameters (pH and moisture), and sensory testing (color, appearance, taste) of meat stored during refrigerated storage for 7 days were evaluated. The results showed that the control sample (without any EO) had the highest pH and moisture content and the difference was significant with the treatments. Treatments containing 1% had the lowest pH and humidity. The bacterial counts of samples were lower than control samples during storage (P<0.05) and the concentrations of 1% EO had the best inhibition of bacterial growth in shrimp meat.
Conclusion: Plants essential oils can be applied by combining with other natural preservatives for enhancing shelf-life extension of food as well as the manufacture of health-oriented products because of The antimicrobial and antioxidant effects.
Keywords: Antibacterial, Antioxidant, Essential oil, Dracocephalum kotschyi, Shelf-life extension