Similarities in Self-Assembly of Proteins and Surfactants: An Attempt to Bridge the Gap - Food Colloids: Self-Assembly and Material Science - page 57

Chapter 4
Similarities in Self-Assembly of Proteins
and Surfactants: An Attempt to Bridge the
Gap
Erik van der Linden and Paul Venema
FOOD PHYSICS GROUP, DEPARTMENT OF AGROTECHNOLOGY
AND FOOD SCIENCES, WAGENINGEN UNIVERSITY, BOMENWEG
2, 6703 HD WAGENINGEN, THE NETHERLANDS
4.1 Introduction
The area of surfactant self-assembly has already received attention for more
than half a century. Considerable progress has been made in connecting the
molecular properties to the assembly morphology and the phase behaviour. A
multitude of different (and rather exotic) types of mesophases with a large
variation in topology can be distinguished. In addition, rheological response
and even shear-induced transitions in morphology and phase behaviour have
been reported. An important technological area is the assembly of surfactants
at an interface.
The area of protein assembly and its associated phase behaviour has also
received considerable attention. The main focus for many years has been on
describing various properties - solubility, crystallization, interfacial assembly,
phase separation and gel formation - in terms of the molecular properties of the
protein or the protein mixture. Since assemblies of proteins are abundant in
food products, the exploration of their morphology, physico-chemical charac-
teristics and mutual interactions is relevant for the engineering of food mate-
rials. But it is only for the past few decades that the morphology of the
assemblies has received more attention. This has mainly been explored in terms
of fractal aggregates. The type of protein assembly that is usually found in
foods (in 3 dimensions) exhibits a morphology that has many branches per unit
length. An extreme case is an infinitely stiff aggregate with zero branches per
unit length, i.e., a rod (with a fractal dimension of 1). This fibrillar type has
been the subject of intensive studies lately in various science areas, including
material science, food science and medical sciences (b-amyloid diseases). Apart
from the fact that the rod morphology is interesting as an extreme case of zero
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