During storage of the emulsions their viscosities decreased generally (Fig 2) while the globule
sizes increased (Fig 1b and Fig 3).
Figure 3: Effect of storage time on the globule size of emulsion, prepared with cassava starch (C)
potato starch (P) and maize starch (M) as emulsifying agents at concentration 4%w/v.
The rate of coalescence of the globules (as measured by the average increase in globule size per
day were (μm day-1) 1.8 (cassava starch emulsion) 3.5 (potato) and 4.6 (maize). Also at the end of
the 7 days storage period, the percentage increase in the mean globule size was lowest in the
cassava starch emulsion and highest in the maize starch emulsion (Table 2).
Table 2: Globule structure (mean and size) of fresh and aged emulsions
Starch |
Globule structure (mean and number) of fresh and aged emulsion | |||||
Fresh emulsion |
Aged emulsion |
% increase in |
% decrease in | |||
Size (mm) |
Number |
Size (mm) |
Number | |||
Cassava |
28.3± 6.1 |
5015 |
70.6± 3.5 |
4540 |
154 |
9.5 |
Potato |
42.2± 6.4 |
4985 |
128.4± 5.2 |
2814 |
205 |
43.5 |
Maize |
44.8± 5.2 |
4875 |
152.4± 4.6 |
2345 |
238 |
51.9 |