Stabilisation of dehydrated nanoemulsions using sugar - protein matrices

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dc.contributor.advisor Roos, Yrjo en
dc.contributor.advisor Fenelon, Mark en Maher, Patrick G. 2016-06-23T10:52:38Z 2016-06-23T10:52:38Z 2015 2015
dc.identifier.citation Maher, P.G. 2015. Stabilisation of dehydrated nanoemulsions using sugar - protein matrices. PhD Thesis, University College Cork. en
dc.identifier.endpage 173 en
dc.description.abstract There are numerous review papers discussing liquid nanoemulsions and how they compare to other emulsion systems. Little research is available on dried nanoemulsions. The objectives of this research were to (i) study the effect of varying the continuous phase of nanoemulsions with different carbohydrate/protein ratios on subsequent emulsion stability, and (ii) compare the physicochemical properties, lactose crystallisation properties, microstructure, and lipid oxidation of spray dried nanoemulsions compared to spray dried conventional emulsions having different water and sugar contents. Nanoemulsions containing sunflower oil (10% w/w), β-casein (2.5–10% w/w) and lactose or trehalose (10–17.5%) were produced following optimisation of the continuous phase by maximising and minimising viscosity and glass transition temperature (Tg’) using mixture design software. Increasing levels of β-casein from caused a significant increase in viscosity, particle size, and nanoemulsion stability, while resulting in a decrease in Tg’. Powders were made from spray drying emulsions/nanoemulsions consisting of lactose or a 70:30 mixture of lactose:sucrose (23.9%), sodium caseinate (5.1%) and sunflower oil (11.5%) in water. Nanoemulsions, produced by microfluidisation (100 MPa), had higher stability and lower viscosity than control emulsions (homogenization at 17 MPa) with lower solvent extractable free fat in the resulting powder. Partial replacement of lactose with sucrose decreased Tg and delayed Tcr. DVS and PLM showed that in powdered nanoemulsions, lactose crystallises faster than in powdered conventional emulsions. Microstructure of both powders (CLSM and cryo-SEM) showed different FGS in powders and different structure post lactose crystallisation. Powdered nanoemulsions had lower pentanal and hexanal (indicators of lipid oxidation) after 24 months storage due to their lower free fat and porosity, measured using a validated GC HS-SPME method, This research has shown the effect of altering the continuous phase of nanoemulsions on microstructure of spray dried nanoemulsions, which affects physical properties, sugar crystallisation, and lipid oxidation. en
dc.description.sponsorship Department of Agriculture, Food and the Marine, Ireland (Food Institutional Research Measure) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2015, Patrick G. Maher. en
dc.rights.uri en
dc.subject Nanoemulsions en
dc.subject Spray drying en
dc.subject Lactose crystallisation en
dc.subject Glass transition temperature en
dc.subject Microstructure en
dc.subject Lipid oxidation en
dc.subject Storage stability en
dc.subject Mixture design en
dc.title Stabilisation of dehydrated nanoemulsions using sugar - protein matrices en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Food Science and Technology) en
dc.internal.availability Full text available en No embargo required en
dc.description.version Accepted Version
dc.contributor.funder Department of Agriculture, Food and the Marine, Ireland en
dc.description.status Not peer reviewed en Food and Nutritional Sciences en Teagasc en
dc.check.type No Embargo Required
dc.check.reason No embargo required en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.embargoformat Not applicable en
dc.internal.conferring Summer 2015 en

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© 2015, Patrick G. Maher. Except where otherwise noted, this item's license is described as © 2015, Patrick G. Maher.
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