Objective of the project - Get insight in the mechanisms that are responsible for the formation and (in)stability of microbubbles as a function of pressure and presence of surfactants and as a function of structural and physical parameters of the microbubble, its shell and ingredients. These relations will be described in a generic quantitative physical model and design rules to manufacture stable microbubbles and foods containing microbubbles as structuring agent. - Get insight in the physical, chemical and sensory behavior of microbubbles as well as the food (foam) systems made out of these microbubbles. These relations will be described in generic quantitative physical models. - Get insight in the relations between the physical and chemical properties of ingredients and the formation, stability and properties of multicomponent aerated systems as a function of time and time-scale and finding the key parameters that control foam behavior. This should lead to design rules and a generic quantitative physical model that describes and predicts the formation and long term stability of these foams in terms of structure and interactions of the multicomponent interfaces as well as the bulk.
Problem definition Aerated foods are important food products because people like their taste and mouth feel. Foams however suffer from deterioration due to creaming, drainage, aggregation coalescence, and disproportionation. Various projects were dedicated to understand these phenomena and a better control of the stability and formation of food foams and sponges was reached. E.g. it was shown that to stabilize air bubbles for months or longer, a thick elastic interfacial layer should be present. Nowadays it is possible to make these so called microbubbles, which find their applications in medical science. Interesting and important applications are also foreseen in food science, like e.g. the replacement of fat as structure element or as surface active particle to stabilize larger air bubbles. However, current microbubble stability is very sensitive for pressure differences and presence of surfactants or other interface destabilizing components. The lack of knowledge controlling microbubble stability limits food industry of using them. The same holds for the limited insights in the relation between sensory mouthfeel of foods containing microbubbles and their mechanical (deformability, stability, fracture) properties.
Strongly related to this is the lack of knowledge about the role of surface and bulk components in multicomponent food systems on the formation and stability of foams. Recent studies indicate that not only the interfacial properties of multicomponent systems control the foam properties but that bulk properties, like the presence of aggregates and fibres, might be even more important. However, the precise role of the interface and the influence of the various ingredients present and their mutual interactions are far from clear.
This project aims at solving the above mentioned problems that limits industry to develop new products that are more healthy, containing less fat and more proteins and fibres, and that are still or even more liked by the consumer than the present available products.
Activities - Development of generic knowledge to the formation of stable multicomponent interfaces, foams, microbubbles and foods made with these microbubbles. - Controlled formation of (multicomponent and/or multilayered) interfacial layers in e.g. Automated Drop Tensiometer (ADT) or Langmuir trough. - Development of a generic models describing the formation, stability and physical/chemical properties of (micro) air bubbles and foams - Testing of (new) materials to manufacturing (multilayered) films - Characterization of the functionality of manufactured new stable microbubbles - Sensory tests to get insights in the impact of microbubbles on the mouthfeel of foods - Development of experimental techniques to determine important food foam quality parameters like bubble size distribution as a function of time. The total time-span of the project is 4 years.
Output The main deliverables are
- New ingredients that improve food foam formation and stabilization. - Insight in the mouthfeel of small air bubbles as function of their rheological and size properties. Generic knowledge (in the form of papers, reports, patents, etc.) and physical models cq. analytical tools that describe and predict the dynamics of the formation and (long-term) stability of multicomponent interfaces in aerated foods as well as a set of mechanisms and strategies to control it. This includes the possibility to use microbubbles as structuring agent to replace fat and stabilize macrobubbles, overcome the loss in emulsifying capacity of old flour and overcome the negative effects of fibres on the stability of food foams.
Scientific relevancy The strategic goal of this proposed project is to develop the knowledge and expertise that is needed to manufacture healthier and tastier food products with a longer shelf life, e.g. realized by replacing fat by microbubbles with improved structural, sensory, and health properties, and overcoming the negative effects of fibres on the stability of food foams. This will contribute to human health, well being, and sustainability. The proposed project, therefore, fits perfectly within the strategic goals of EL&I and is therefore of great relevancy.
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