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curve (R
2
¼
0.99). All measurements are expressed as the mean and standard
deviation of at least two full experimental replications.
29.3 Experimental Results and Preliminary Modelling
A cocktail of four volatiles was investigated, and the trends seen were similar
for all. Therefore only results for EH will be reported for clarity. The value of
K
ge
was found to decrease with oil volume fraction for model emulsions
containing liquid and solid n-eicosane droplets (Figure 1), but more rapidly
for liquid droplets than for solid ones. Figure 1(a) shows that K
ge
for liquid
droplets depends only upon the volume fraction of oil; indeed an unemulsified
(a)
12
◊
d
32
= 0.97
µ
m
d
32
= 0.44
10
m
∆
d
32
= 0.27
µ
m
♦
Bulk lipid and water mixture
µ
8
6
4
2
0
0
10
20
30
40
Emulsion Lipid Content / %
12
◊
d
32
= 0.97
µ
m
d
32
= 0.44
(b)
10
m
∆
d
32
= 0.27
µ
m
µ
8
6
4
2
0
0
10
20
30
40
Emulsion Lipid Content / %
Figure 1 Effective partition coefficient K
ge
of ethyl heptanoate (EH) for an n-eicosane
emulsion of (a) liquid and (b) solid droplets with various particle sizes. The
lines in (a) are calculated from bulk partition coefficients using a volume
partitioning model [Equation (2)]. The broken lines in (b) are calculated based
on a surface-binding model fit to
f
o
4 0.1 (K
iw
¼
4.5
10
6
m). The solid lines
in (b) are based on the combined surface binding/droplet dissolution model
described in the text
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