NFOK15009U Food Colloids
MSc Programme in Food Science and Technology
Foods are complex materials that consist of multiple dispersed and continuous phases. Foods consist for example of simple solutions, crystals of sugars and fats, droplets of oil, dispersed fibers, polymers and proteins. Foods can be characterized as thin and viscous solutions, gels and pastes as well as solids. Food colloids are found in all kinds of food from dairy products to beer. Food colloids has internal surfaces that can be charged and adsorb surface active molecules. The particles in foods interact, particles can grow or shrink in size, particles can coalesce and aggregate and food are dynamic systems where liquids can become solid and vice versa.
The course is a fully theoretical course about the fundamental forces stabilizing and destabilizing colloidal systems and the experimental methods to study properties such as structure, functionality and changes in such properties of colloidal foods.
Introductions to dispersed systems: gels, emulsions, micro and nano- emulsions, sols and foams.
Forces between particles in foods. Free energy, phases and phase diagrams. Hydrophobicity and hydrofilicity
Surfaces in foods: surface tension, Gibbs adsorption isotherm. Contact angles and wetting. Ionic strength and charged surface, surface and zeta potential.
Phase behavior of lipids and other amphifilic molecules.
Emulsions and emulsifiers. Emulsification and Emulsions breakdown.
Foams and foaming agents. Whippable emulsions.
Solids dispersions and dispersant. Sedimentation, haze and turbidity.
Experimental methods: Rheology Differential scanning calorimetry, light, x-ray and neutron scattering, Microscopy and other imaging techniques.
Stability of foods and colloidal stability. Flavor distribution and flavor release from colloidal systems.
- Knowledge of the fundamental of dispersions colloidal systems.
- Knowledge of the interactions and forces that stabilized and destabilizes colloidal systems.
- Knowledge of phase diagrams and the theory behind phase diagram.
- Knowledge of surface chemistry and theory of surface tension.
- Skills in presenting and explaining complex relations and theory.
- Skills in applying theoretical concepts and making calculations.
- Competences in describing and understanding complex food systems using colloidal chemical concepts.
- Competences in understanding and preventing colloidal floors in food
- Competences in choosing experimental techniques to study properties of foods, based on colloidal chemical knowledge
See Absalon for a list of course literature.
- 7,5 ECTS
- Type of assessment
- Oral examination, 20 minOral examination without preparation time. The examination takes its starting point in posters produced by the student.
The student draws a poster and presents it. The presentation soon develops into a scientific conversation with the examiners. The examiners pose questions in the full curriculum and might include supplementary materials (graphs, table, pictures and drawings).
- Exam registration requirements
Students must prepare and present posters and take part in poster sessions.
- Without aids
- Marking scale
- 7-point grading scale
- Censorship form
- No external censorship
Several internal examiners
Same as ordinary exam.
Lacking posters must be produced and handed in two weeks prior to re-examination.
Criteria for exam assesment
See Learning Outcome
- Theory exercises
- Class Seminar
- Project work