(Demetriades, Coupland, & McClements, 1997). Evidence for aggregation
and coalescence of emulsion oil droplets was obtained
via the Mastersizer with and without prior ultrasonic treatment for
30 s. Samples for the long-term stability tests had 0.05% (w/v) sodium
azide added as an antimicrobial agent. Freeze-thaw stability
of the emulsions was examined after 1 week storage in a freezer
at 18 C. The frozen emulsions were thawed in a water bath at
40 C for 30 min and then visually observed. Destabilized free oil
was determined as described earlier (Palanuwech, Potineni,
Roberts, & Coupland, 2003).
2.3. Statistics
All experiments were conducted in triplicate with freshly
prepared samples of suspensions or emulsions. Statistical analyses
were performed using Microsoft Excel ver. 2010 for
Windows.
3. Results and discussion
3.1. Characterisation of SPI macrogels and gel particles
It is well-known that the rheological properties of SPI gels