Over the recent years, structuring of oil into ‘organogels’ or ‘oleogels’ has gained much attention amongst colloid-, material,- and food scientists. Potentially, these oleogels could be used as an alternative for saturated- and trans fats in food products. To develop oleogels as a suitable replacement for saturated fats, the requirements go beyond merely providing a solid appearance to an otherwise liquid oil. For food applications, the gelator should be a well-known ingredient for food manufacturers, have a good nutritional value, and contribute to ‘clean labelling’. Proteins meet all these requirements and could therefore be of high potential. The general concept of protein-based oil gelation fits well into the growing general interest to reduce solid fats from food products along with increase in flexibility in terms of choice of ingredients. In this thesis, the suitability of proteins as a structuring agent for liquid oil was investigated and the rheological behaviour was described. To create protein oleogels, heat-set whey protein gels and protein aggregates, or ‘building blocks’, are created in an aqueous environment. Then, the aqueous phase is exchanged for a liquid oil phase via an intermediate solvent. It was show that by using this procedure, the created protein building blocks are highly efficient in creating oleogels. It is encouraging to see that the interactions between proteins can be altered by simple changes to the system, such as changing the oil type, water addition, or applying a heat treatment. This leads to the possibility to effectively and substantially tune the rheological properties of the final oleogel, such as its gel strength or yielding behaviour.
