Over Lipid and Protein Oxidation in Interface-dominated Food Systems: Interrelation and Functional Consequences

Lipid and Protein Oxidation in Interface-dominated Food Systems: Interrelation and Functional Consequences

Avondlezing door dr. C.C. Berton-Carabin georganiseerd door de Chemische Kring Midden Nederland.

Many food systems are made of several immiscible phases, for example, oil and water. The resulting droplets of one liquid phase dispersed into the other form emulsions, i.e., interface-dominated materials, as the small droplet size leads to a high interfacial area. Consequently, the contacts between both phases are promoted, and the components that locate at the oil-water interface play a key role in the physicochemical stability of food emulsions.

A major chemical degradation in food emulsions is lipid oxidation, which decreases their nutritional and sensory properties. In these complex and multicomponent systems, lipid oxidation may occur simultaneously with co-oxidation phenomena, which affect other molecules such as proteins. It is well-established that protein oxidation degrades the sensory properties of foods, such as texture, and decreases protein digestibility. However, the consequences of protein oxidation on their interfacial properties have hardly been explored. We recently found that protein oxidation substantially decreased the elasticity and interconnectivity of whey protein layers at the oil-water interface, which could, in turn, affect their emulsion stabilizing properties.

Although the interplay between lipid and protein oxidation in complex food systems has been an emerging question lately, a number of related aspects remain controversial or have hardly been investigated. For instance, it is well admitted that lipid and protein oxidation in emulsions occur concomitantly, but it is not clear which of the two phenomena starts first. We found that that the involvement of dairy proteins in oxidative phenomena in emulsions depends to a large extent on the protein partitioning between the continuous aqueous phase and the oil-water interface: non-adsorbed proteins in the continuous phase can effectively protect the lipid phase against oxidation, without being themselves subjected to extensive oxidative degradation. Conversely, proteins adsorbed at the oil-water interface undergo early and extensive modifications in oxidizing emulsions, and are likely to promote the propagation of radical-chain reactions to the dispersed lipids.

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Curriculum vitae:
Professional experience:
2013 (July)-present Assistant professor, Wageningen University and Research,
Food Process Engineering group.
Research theme: Food Interface Design:
How the interface can be used to control food functionality
2013 (March-August) Post-doctoral scientist, Danone-Nutricia Research (Utrecht, NL).
Project: Characterisation of the interfacial structure in food emulsions.
2011-2013 Post-doctoral scholar, The Pennsylvania State University, Department of Food Science (USA).
Project: Exploring the use of nanoemulsions as delivery systems of lipophilic ingredients for food applications.
Education and academic qualifications:
2008-2011 PhD in Food Science, University of Nantes and INRA (The French National Institute for Agricultural Research) (Nantes, France).
Project: Controlled design of interfaces to protect emulsified lipids against oxidation.
2005-2008 MSc in Food Science and Technology, University of Bordeaux – ENSCBP (Ecole Nationale Supérieure de Chimie, Biologie et Physique) (Bordeaux, France).
2003-2005 BSc in Life Sciences, Food Science specialisation, University of Angers (France).

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