title: Microemulsions as Potential Carriers of Nisin: Effect of Composition on Structure and Efficacy.
abstract: Water-in-oil (W/O) microemulsions based on either refined olive oil (ROO) or sunflower oil (SO), distilled monoglycerides (DMG), and ethanol were used as nisin carriers in order to ensure its effectiveness as a biopreservative. This work presents experimental evidence on the effects of ethanol concentration, hydration, the nature of oil, and the addition of nisin on the nanostructure of the proposed inverse microemulsions as revealed by electrical conductivity measurements, dynamic light scattering (DLS), small angle X-ray scattering (SAXS), and electron paramagnetic resonance (EPR) spectroscopy. Modeling of representative SAXS profiles was applied to gain further insight into the effects of ethanol and solubilized water content on the inverse swollen micelles' size and morphology. With increasing ethanol content, the overall size of the inverse micelles decreased, whereas hydration resulted in an increase in the micellar size due to the penetration of water into the hydrophilic core of the inverse swollen micelles (hydration-induced swelling behavior). The dynamic properties of the surfactant monolayer were also affected by the nature of the used vegetable oil, the ethanol content, and the presence of the bioactive molecule, as evidenced by EPR spin probing experiments. According to simulation on the experimental spectra, two populations of spin probes at different polarities were revealed. The antimicrobial effect of the encapsulated nisin was evaluated using the well diffusion assay (WDA) technique against Lactococccus lactis. It was found that this encapsulated bacteriocin induced an inhibition of the microorganism growth. The effect was more pronounced at higher ethanol concentrations, but no significant difference was observed between the two used vegetable oils (ROO and SO).
authors: Institute of Biology Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.|MTM, Faculty of Science and Engineering, Örebro University , Örebro, Sweden.
authors: Maria D
authors: MD
authors: Chatzidaki
authors: Laboratory of Dairy Research, Department of Food Science and Human Nutrition, Agricultural University of Athens , Athens, Greece.
authors: Konstantinos
authors: K
authors: Papadimitriou
authors: Laboratory of Dairy Research, Department of Food Science and Human Nutrition, Agricultural University of Athens , Athens, Greece.
authors: Voula
authors: V
authors: Alexandraki
authors: Institute of Biology Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.
authors: Eirini
authors: E
authors: Tsirvouli
authors: Institute of Biology Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.
authors: Zena
authors: Z
authors: Chakim
authors: Aghiad
authors: A
authors: Ghazal
authors: Kell
authors: K
authors: Mortensen
authors: Anan
authors: A
authors: Yaghmur
authors: Laboratory for Biointerfaces, Department of Materials Meet Life, Empa. Swiss Federal Laboratories for Materials Science and Technology , St. Gallen, Switzerland.
authors: Stefan
authors: S
authors: Salentinig
authors: Institute of Biology Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.
authors: Vassiliki
authors: V
authors: Papadimitriou
authors: Laboratory of Dairy Research, Department of Food Science and Human Nutrition, Agricultural University of Athens , Athens, Greece.
authors: Effie
authors: E
authors: Tsakalidou
authors: Institute of Biology Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.|MTM, Faculty of Science and Engineering, Örebro University , Örebro, Sweden.
authors: Aristotelis
authors: A
authors: Xenakis
mesh_terms: D004337:Drug Carriers; D004553:Electric Conductivity; D004655:Emulsions; D000431:Ethanol / Q000737:chemistry*; D013294:Lactococcus lactis / Q000187:drug effects* / Q000254:growth & development; D008823:Micelles; D050178:Monoglycerides / Q000737:chemistry; D009561:Nisin / Q000737:chemistry / Q000494:pharmacology*; D000069463:Olive Oil / Q000737:chemistry; D013113:Spin Labels; D000074242:Sunflower Oil / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D004655:Emulsions; D008823:Micelles; D050178:Monoglycerides; D000069463:Olive Oil; D013113:Spin Labels; D000074242:Sunflower Oil; D014867:Water; D009561:Nisin; D000431:Ethanol