Application of Self-assembly Principles in Foods
M. Michel, P-A. Aichinger, E. Kolodziejczyk, L. Sagalowicz, E. Hughes, H.J. Watzke and M.E. Leser
Nestlé Research Center, CH
self-assembly, food production, food colloids, casein micelles, xanthan, emulsifier-based colloids
The challenge of future food production lies in providing delightful and healthy foods. Relevant properties of foods, such as texture, taste and nutritional functionality are not simply the result of the presence of ingredients mixed together during processing, but the outcome of a complex three-dimensional structure with large interface areas. Important parameters to control are length scales ranging from the nano- to the millimeters as well as time scales covering microseconds during processing up to years during shelf-life. Structural organization on those length and time scales is governed by molecular and colloidal interactions, which are controlled via processing conditions, permitting the food processor to tailor food structure and stability. Most technologies to build up structures consist of three main steps: food formulation, mechanical and thermal treatments. These steps are designed to 1) produce a system of desirable composition, 2) to form the structure and shape of the system and 3) to fix the products structure. The current approach to form food microstructures is achieved through energy input such as homogenization, whipping and milling, also called ‘Top-down Structuring’. Structural entities formed in this way are very often thermodynamically unstable and show a high degree of poly-dispersity due to inhomogeneous energy distribution within the processing unit. An alternative route to effectively control and design structure formation is given by the ‘Bottom-up Structuring’ approach. The essence of ‘Bottom-up Structuring’ is to focus on the control of relevant interactions (hydrophobic, Van der Waals, electrostatic inter-actions, Brownian forces etc.) on a molecular and colloidal level, leading to self-assembled structures. These structures are spontaneously formed and some are thermodynamically stable. We will discuss strategies for applying self-assembly principles using food colloids such as casein micelles in mixture with xanthan as well as emulsifier-based colloids.
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Nanotech 2005 Conference Program Abstract