3.7.2. Changes in particle size of emulsion during storage
Changes in particle size of emulsions stabilised by 1.0% gelatin
and gelatin modified with oxidised tannic acid during storage at
room temperature for 12 days are shown in Fig. 4A. Particle size
of both emulsions gradually increased with increasing storage
time. For emulsions stabilised by the control gelatin, the particle
size increased from 0.33 ± 0.02 to 0.44 ± 0.02 lm within 12 days
of storage, whereas that of the emulsion stabilised by gelatin modified
with oxidised tannic acid increased from 0.37 ± 0.02 to
0.46 ± 0.03 lm. This result might be due to individual droplet
growth (Ostwald ripening) or droplet aggregation (flocculation or
coalescence) during storage (Djordjevic et al., 2008). At day 12 of
storage, no difference in the size of the oil droplet was noticeable
between both emulsions though a smaller size of droplet was
found in the emulsion stabilised by control gelatin at day 0. This
indicated that gelatin modified by oxidised tannic acid yielded the similar emulsion stability to gelatin without modification at
the extended storage.