Chemistry Reference
In-Depth Information
It showed that the perceived acidity was related to the outer water
phase and not to the overall content of acid in the product. This finding
suggests that if the structures can be made, then they will have the
desired properties.
As discussed earlier, recent work (Frasch-Melnik
et al
., 2009) has
shown that shells can be produced around the inner droplets. It has
been shown that if the shells are controlled carefully, they result in an
intact structure. These perfect shells then resist the osmotic pressure
differences of having 1% salt in one water phase and 0% salt in the
other. These structures have been demonstrated to be stable for greater
than 6 months with less than 5% leakage of the salt between the phases.
The potential of duplex emulsions for salt reduction in wet products
(i.e. the difficult task) will be tested in the near future.
10.3.3
Fat replacement with air-filled emulsion
Another stratagem is to replace the fat droplets in an emulsified product
with stabilised air cells that physically (size and shape) and rheologically
resemble the fat droplets they are replacing.
The first question is whether air can change the lubrication and mouth-
feel properties of a product? Recently, there has been some research in
this field. Heuer and Norton (unpublished data) investigated the role of
air in tribology using dairy cream alternatives. They studied the effect
of taking fat out of a product and then compared this when air was
whipped in. As Fig. 10.11 shows, air has increased the lubrication of the
low-fat emulsion. The authors argue that this is a consequence of in-
creasing the proportion of an included phase. This has the effect of
Full-fat whipping cream
Low-fat whipping cream
Aerated cream alternative
0.1
0.05
0
10
1
10
2
10
3
Speed (mm/second)
Fig. 10.11
Stribeck curves for a full-fat whipping cream (
), a low-fat whipping cream
alternative (
) and an aerated cream alternative (
•
).
