Self-Assembled Liquid Particles: How to Modulate their Internal Structure - Food Colloids: Self-Assembly and Material Science - page 82

10

55°C
50°C
45°C

EME

40°C
35°C
30°C
25°C
20°C
15°C

MCP

1

Hexosomes
+ MCP

Hexosomes

5°C

0.1

1 2 3 4

q (nm -1 )
Figure 12 Thermal transformation at d ¼ 77 from hexosomes to EME via micellar
cubosomes for R -(+)-limonene-loaded Dimodan-based dispersions. For clar-
ity the SAXS curves are shifted vertically

systems at very low temperatures, lamellar phases (zero curvature) are not
observed; at 11C only phases with negative curvature are observed - cubo-
somes, hexosomes, micellar cubosomes, and EME particles. Thus, the particles
do maintain the self-assembled structures found at higher temperatures. This is
important for storage reasons.
Here, we have reported on the effect of varying temperature and the
solubilized amount of oil on the structural transitions observed in MLO-based
dispersions. At a given temperature, the addition of oil induces a transition of
the internal structure from the bicontinuous cubic phase (Pn3m) to the reversed
hexagonal (H 2 ) and then to the isotropic liquid phase (W/O microemulsions).
We have found an Fd3m phase (reverse discontinuous micellar cubic), which is
formed at a specific oil/monoglyceride weight ratio. It is situated between the
H 2 phase and the isotropic liquid phase (W/O microemulsion). The present
work proves that the structural transformation in the dispersed particles from
H 2 (hexosomes) to the W/O microemulsion system (EME) may occur directly
or indirectly via an emulsified intermediate phase.

5.3.3 Control of the Internal Self-Assembled Structure
We showed above that we can tune the internal structure of monoglyceride-
based particles upon addition of a certain amount of oil. Here we show that we
can reverse the structural change using an additional surface-active component.
In particular, DGMO has a counter effect to that of the oil (TC), in that it