Chemistry Reference
In-Depth Information
Figure 9 X-ray diffraction profiles from samples containing 2.5-wt% phytosterol +
various concentrations of lycopene: (a) 100 ppm, (b) 200 ppm or (c) 400 ppm.
Intensity is plotted against wave number q
than this diffraction peak. The other missing Bragg diffraction peaks could not
be identified because of the low intensity and the high noise level.
At lower and higher concentrations of lycopene (100 and 400 ppm), the
SAXS diffractions are similar to those observed for the pure Q
L
system, but
with lower intensities and lower resolutions. The Q
L
system containing 2.5-
wt% phytosterol + 100-ppm lycopene produced five Bragg peaks (
O
2:
O
5:
O
6:
O
8:
O
9). A sample containing 2.5-wt% phytosterol + 400-ppm lycopene
also had five Bragg peaks, but with different relations (
O
2:
O
6:
O
7:
O
9:
O
10).
This means that the initial permitted Bragg peaks of the P4
2
32 space group in
these systems was reduced and long-range order also was reduced. It should
therefore be stressed that, while at 200 ppm of lycopene the only Bragg peak
missing is the one at
O
3, at 100 ppm of lycopene the peaks at
O
3 and
O
4are
missing and at 400 ppm of lycopene the ones at
O
3,
O
4 and
O
5 are missing.
The pattern of SAXS scattering indicates clear evidence of some long-range
order; therefore, the structures may have an inner order somewhere between
cubic and sponge assemblies.
From the trend of the missing peaks we can also deduce that, at low and
medium levels of lycopene (up to 200 ppm), the presence of the guest molecule
adds to the internal order, while at more elevated levels (ca. 400 ppm) the
presence of the guest molecule has a destructive effect, and the system symme-
tries are minor or small.
6.4 Conclusions
The scientific value of these results is threefold.
(i) We have established that the Q
L
phase has the capability and capacity to
solubilize guest molecules of different natures.
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