Self-Assembly in Food – A New Way to Make Nutritious Products - Food Colloids: Self-Assembly and Material Science - page 30

Figure 4 Solubilization of free phytosterols in (a) an emulsion and (b) an emulsified L2
phase. Polarized light microscopy clearly indicates plant sterol crystals in the
emulsion after a storage time of 4 weeks at 41C, whereas the emulsified L2 phase
does not indicate any traces of crystalline phytosterols
(Copyright Nestec Ltd (2006))
concepts have to establish a solid link, on the one hand, between the biological
mechanisms of perception and digestion, and, on the other, the engineering of
food structures that can deliver the desired sensorial and nutritional impacts.
Analysing the processes involved in food production, consumption and diges-
tion, it becomes evident that the essential properties of a food critically depend on
phenomena or processes taking place over various spatial and temporal ranges.
The length-scales involved are molecular, supra-molecular, colloidal and macro-
scopic, and the time-scales range from nanoseconds (enzyme reactions) to years
(shelf-life). Key physico-chemical mechanisms, thermodynamic as well as kinetic,
have to be identified where the control of events at the molecular and nanoscopic
scales is critical for product performance, e.g., the controlled delivery of a
bioactive. An interesting colloidal concept is the so-called 'pro-colloid' approach,
where the colloid is designed in a way that it delivers its benefits in the context of
the involved bio-transformation, e.g., during consumption or digestion. Possible
built-in functionalities are time-controlled events (e.g., retarded or sequential
release), activation of enzymes or precursors, and inactivation or extraction of
intermediates.
At present the design of delivery colloids is a very slow process because we lack
efficient in vitro models for studying digestion and nutrient liberation. There is a
strong need to set up reasonable methodologies for in vitro assessment of delivery
colloid performance in the context of the food complexity and digestion. Once
properly established, this should considerably increase the range of colloidal
structures providing sensorial and nutritional benefits. Furthermore, modular
concepts using a variety of colloids targeted to specific nutritional situations will
then offer solutions for personalized nutrition. The successful realization of these
concepts requires a strong interdisciplinary approach, involving physics, chem-
istry, colloid science, process-engineering, biology and nutrition.
References
1. P.R. Guesry, Forum Nutr., 2005, 57, 73.
2. M.B. Katan and N.M. de Roos, Crit. Rev. Food Sci. Nutr., 2004, 44, 369.