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Microemulsion versus emulsion as effective carrier of hydroxytyrosol
Örebro University, School of Science and Technology, Örebro University, Sweden. Natl Hellen Res Fdn, Inst Biol Med Chem & Biotechnol, Athens 11635, Greece.
Natl Hellen Res Fdn, Inst Biol Med Chem & Biotechnol, Athens 11635, Greece..
Univ Bordeaux, CBMN, Lab Chim & Biol Membranes & Nanoobjets, Bordeaux, France..
Natl Hellen Res Fdn, Inst Biol Med Chem & Biotechnol, Athens 11635, Greece..
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2016 (English)In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 137, no 1, 146-151 p.Article in journal (Refereed) Published
Resource type
Text
Abstract [en]

Two edible Water-in-Oil (W/O) dispersions, an emulsion that remains kinetically stable and a microemulsion which is spontaneously formed, transparent and thermodynamically stable, were developed for potential use as functional foods, due to their ability to be considered as matrices to encapsulate biologically active hydrophilic molecules. Both systems contained Medium Chain Triglycerides (MCT) as the continuous phase and were used as carriers of Hydroxytyrosol (HT), a hydrophilic antioxidant of olive oil. A low energy input fabrication process of the emulsion was implemented. The obtained emulsion contained 1.3% (w/w) of surfactants and 5% (w/w) aqueous phase. The spontaneously formed microemulsion contained 4.9% (w/w) of surfactants and 2% (w/w) aqueous phase. A comparative study in terms of structural characterization of the systems in the absence and presence of HT was carried out. Particle size distribution obtained by Dynamic Light Scattering (DLS) technique and interfacial properties of the surfactants' layer, examined by Electron Paramagnetic Resonance (EPR) spectroscopy indicated the involvement of HT in the surfactant membrane. Finally, the proposed systems were studied for the scavenging activity of the encapsulated antioxidant toward galvinoxyl stable free radical showing a high scavenging activity of HT in both systems.

Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 137, no 1, 146-151 p.
Keyword [en]
Emulsion, Microemulsion, Hydroxytyrosol, DLS, EPR, Antioxidant activity
National Category
Other Chemistry Topics
Research subject
Chemistry
Identifiers
URN: urn:nbn:se:oru:diva-50110DOI: 10.1016/j.colsurfb.2015.04.053ISI: 000367491200017PubMedID: 25999235Scopus ID: 2-s2.0-84951573458OAI: oai:DiVA.org:oru-50110DiVA: diva2:925737
Available from: 2016-05-03 Created: 2016-05-03 Last updated: 2016-05-03Bibliographically approved
In thesis
1. Formulation and characterization of W/O nano-dispersions for bioactive delivery applications
Open this publication in new window or tab >>Formulation and characterization of W/O nano-dispersions for bioactive delivery applications
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The main objective of this study was the formulation of food-grade water-in-oil (W/O) nano-dispersions based mainly on medium or long-chain triglycerides. Two types of dispersions were formulated and structurally compared, namely emulsions and microemulsions. The systems were used as matrices for encapsulating targeted bioactive molecules with specific characteristics such as antioxidants or peptides.

The structural characterization of the formulated systems was investigated using techniques such as Electron Paramagnetic Resonance (EPR) spectroscopy, Dynamic Light Scattering (DLS), Cryogenic Transmission Electron Microscopy (Cryo-TEM) and Small Angle Xray Scattering (SAXS). The existence of swollen inverse micelles was revealed for the case of microemulsions whereas larger droplets still at the nano-scale were observed for the case of emulsions. Structural differences in the presence of the bioactive molecules or induced by the alteration of components were also observed.

In order to study the efficacy of the formulations, the proposed loaded systems were assessed either using EPR spectroscopy or Well Diffusion Assay (WDA) depending on the bioactive molecule. It was found that the encapsulated molecules retained their claimed characteristics when encapsulated to the proposed matrices.

Finally, some of the formulated dispersions were investigated for their behavior under gastrointestinal (GI) conditions. A two-step digestion model using recombinant Dog Gastric Lipase (rDGL) and Porcine Pancreatic Lipase (PPL) was proposed to simulate lipid hydrolysis in humans. The studies revealed significant decrease of the rDGL specific activity in the presence of the microemulsion while in the presence of lower percent of surfactants (case of emulsion) no alterations were observed.

Place, publisher, year, edition, pages
Örebro: Örebro university, 2016. 77 p.
Series
Örebro Studies in Chemistry, ISSN 1651-4270 ; 16
Keyword
nano-dispersions, encapsulation, food, DLS, EPR, Cryo-TEM, SAXS, pH-stat, digestion, antioxidants, gastric lipase, pancreatic lipase
National Category
Other Chemistry Topics
Research subject
Chemistry
Identifiers
urn:nbn:se:oru:diva-49454 (URN)978-91-7529-141-3 (ISBN)
Public defence
2016-05-26, Billbergska huset, hörsal B, Örebro universitet, Fakultetsgatan 1, Örebro, 10:15 (English)
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Available from: 2016-03-22 Created: 2016-03-22 Last updated: 2016-05-04Bibliographically approved

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