Ultrasonication-assisted formation and characterization of geraniol and carvacrol-loaded emulsions for enhanced antimicrobial activity against food-borne pathogens
- 53 Downloads
Gum arabic stabilised oil-in-water emulsions were prepared through ultrasonication approach for the incorporation of natural, plant-based antimicrobial compounds, geraniol and carvacrol. The oil phase of formulated emulsions was constituted with geraniol and carvacrol, incorporated at various ratios of 1:0, 2:1, 1:1, 1:2, and 0:1 (v/v). The ultrasonication procedure was followed using a frequency of 20 kHz at 40% amplitude for 5 min. These emulsion systems were characterized for mean particle diameter, polydispersity index, ζ-potential, storage stability and creaming index. In addition, emulsion microstructure was studied using confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Evaluation of antimicrobial activity of the functional emulsions was carried out against Gram-positive bacteria Bacillus cereus MTCC 430 and Gram-negative bacteria Escherichia coli MTCC 443. The results demonstrated that geraniol: carvacrol (1:1) emulsion formulation displayed good stability with particle size (202.7 ± 4.17 nm), polydispersity (0.282 ± 0.001), ζ-potential (− 19.37 ± 0.06 mV) and no visible separation of cream was observed. Furthermore, the CLSM and TEM observations confirmed the presence of stable emulsion. In addition, the antimicrobial susceptibility tests demonstrated collaborative activity and prolonged antibacterial efficacy for the combined essential oil-based emulsion against both the model bacterial pathogens.
KeywordsEssential oil emulsion Geraniol Carvacrol Food-borne pathogens Antimicrobials
The authors would like to thank the Science and Engineering Research Board, Govt. of India, for providing financial support for conducting research work through a research grant to Dr. Preetam Sarkar (YSS/2015/000546). The authors would also like to acknowledge technical support extended by Sukanta, Susanta Pradhan, and Subhabrata Chakraborty, National Institute of Technology, Rourkela, for assistance with Zetasizer Nano ZS, confocal laser scanning microscopy imaging and TEM imaging, respectively.
Compliance with ethical standards
Conflict of interest
The authors report no conflict of interest.
- Abdollahzadeh E, Rezaei M, Hosseini H (2014) Antibacterial activity of plant essential oils and extracts: the role of thyme essential oil, nisin, and their combination to control Listeria monocytogenes inoculated in minced fish meat. Food Control 35:177–183. https://doi.org/10.1016/j.foodcont.2013.07.004 CrossRefGoogle Scholar
- Food and Drug Administration (2017) Food additives permitted for direct addition to food for human consumption: synthetic flavoring substances and adjuvants. In: Code of federal regulations, Title 21, vol 3, Part 182.20. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=182.20
- Jain A, Thakur D, Ghoshal G, Katare O, Shivhare U (2015) Microencapsulation by complex coacervation using whey protein isolates and gum acacia: an approach to preserve the functionality and controlled release of β-carotene. Food Bioprocess Technol 8:1635–1644. https://doi.org/10.1007/s11947-015-1521-0 CrossRefGoogle Scholar
- Mirhosseini H, Tan CP, Hamid NSA, Yusof S (2008) Optimization of the contents of Arabic gum, xanthan gum and orange oil affecting turbidity, average particle size, polydispersity index and density in orange beverage emulsion. Food Hydrocoll 22:1212–1223. https://doi.org/10.1016/j.foodhyd.2007.06.011 CrossRefGoogle Scholar
- Oussalah M, Caillet S, Saucier L, Lacroix M (2007) Inhibitory effects of selected plant essential oils on the growth of four pathogenic bacteria: E. coli O157: H7, Salmonella Typhimurium, Staphylococcus aureus and Listeria monocytogenes. Food Control 18:414–420. https://doi.org/10.1016/j.foodcont.2005.11.009 CrossRefGoogle Scholar
- Salvia-Trujillo L, Rojas-Grau MA, Soliva-Fortuny R, Martin-Belloso O (2014) Impact of microfluidization or ultrasound processing on the antimicrobial activity against Escherichia coli of lemongrass oil-loaded nanoemulsions. Food Control 37:292–297. https://doi.org/10.1016/j.foodcont.2013.09.015 CrossRefGoogle Scholar
- Salvia-Trujillo L, Rojas-Grau A, Soliva-Fortuny R, Martin-Belloso O (2015) Physicochemical characterization and antimicrobial activity of food-grade emulsions and nanoemulsions incorporating essential oils. Food Hydrocoll 43:547–556. https://doi.org/10.1016/j.foodhyd.2014.07.012 CrossRefGoogle Scholar
- Silva-Angulo AB, Zanini SF, Rosenthal A, Rodrigo D, Klein G, Martinez A (2015) Combined effect of carvacrol and citral on the growth of Listeria monocytogenes and Listeria innocua and on the occurrence of damaged cells. Food Control 53:156–162. https://doi.org/10.1016/j.foodcont.2015.01.028 CrossRefGoogle Scholar
- Sugumar S, Ghosh V, Nirmala MJ, Mukherjee A, Chandrasekaran N (2014) Ultrasonic emulsification of eucalyptus oil nanoemulsion: antibacterial activity against Staphylococcus aureus and wound healing activity in Wistar rats. Ultrason Sonochem 21:1044–1049. https://doi.org/10.1016/j.ultsonch.2013.10.021 CrossRefGoogle Scholar
- Ultee A, Kets EP, Smid EJ (1999) Mechanisms of action of carvacrol on the food-borne pathogen Bacillus cereus. Appl Environ Microbiol 65:4606–4610Google Scholar
- Visalli MA, Jacobs MR, Appelbaum PC (1996) MIC and time-kill study of activities of DU-6859a, ciprofloxacin, levofloxacin, sparfloxacin, cefotaxime, imipenem, and vancomycin against nine penicillin-susceptible and -resistant pneumococci. Antimicrob Agents Chemother 40:362–366Google Scholar
- WHO (2015) WHO estimates of the global burden of foodborne diseases: foodborne disease burden epidemiology reference grou. World Health Organization, Geneva, pp 2007–2015Google Scholar