Chemistry Reference
In-Depth Information
Chapter 5
Self-Assembled Liquid Particles: How to
Modulate their Internal Structure
Samuel Guillot,
1
Anan Yaghmur,
1
Liliana de Campo,
1
Stefan
Salentinig,
1
Laurent Sagalowicz,
2
Martin E. Leser,
2
Martin
Michel,
2
Heribert J. Watzke
2
and Otto Glatter
1
1
INSTITUTE
OF
CHEMISTRY,
UNIVERSITY
OF
GRAZ,
HEINRICHSTRASSE 28, A-8010 GRAZ, AUSTRIA
2
NESTLE
ยด
RESEARCH CENTER, VERS-CHEZ-LES-BLANC, CH-1000
LAUSANNE 26, SWITZERLAND
5.1 Introduction
In the modern type of food formulation, it is of increasing importance to have
the essential components arranged in such a way that their functionality and
bioavailability are optimized. This must be achieved and understood on the
molecular level. Thus, self-assembly is a central mechanism for efficient struc-
tural design.
1
Moreover, for the successful incorporation of different functional
molecules, it is also necessary to generate systems with hydrophilic and
hydrophobic regions of large interfacial area. Microemulsions are self-assem-
bling and thermodynamically stable systems that fulfil these conditions. The
food-grade multicomponent microemulsions, which have been described
recently,
2,3
are often applied in high concentrations, and so it is necessary to
study the structure and the dynamics at high concentrations. This is possible
with modern scattering methods.
4
Nevertheless, equilibrium systems such as
micelles or microemulsions have one essential drawback: they may change
dramatically, or even disassemble, if they are mixed with other systems or if just
some parameters such as temperature or salinity are changed. Hierarchically
organized systems can potentially avoid these difficulties.
Food emulsifiers such as monoglycerides or phospholipids are known to
form self-assembly structures when added to water. The lamellar phase formed
by phospholipids has attracted the most interest thus far due to its easy
transformation into vesicles or liposomes. Unsaturated monoglycerides give
rise to a series of reverse lyotropic liquid crystalline phases, such as the reverse
bicontinuous,
hexagonal,
and microemulsion
phases. However,
the
69
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