3. Results and discussion
3.1 Emulsion storage stability after seven days
Phase separation in the W/O emulsions was visually observed and recorded (Figure 1). After 7 days, a clear oil phase was separated at the top in most emulsions due to water droplet sedimentation. Higher emulsion height or lower oil phase separation indicates better emulsion stability. In Figure 1, the control emulsions were indicated with no-additive (S0). The emulsions with only salts are indicated as S0.125 (0.125% sodium chloride) and Ca0.045 (0.045% calcium chloride). For the emulsions without any additive (S0), CO emulsions showed larger phase separation (lowest stability) compared to MO emulsions (Figure 1A and 1B). The addition of S0.125 showed a significant increase in emulsions height compared to S0 in both bulk oils. The emulsions with S0.125 and AA or CA demonstrated higher emulsion height and lower oil separation for both CO and MO than those with only AA or CA. The addition of Ca also increased emulsion height compared to S0 in both oils (Figure 1C). The emulsions with only LMP reported a higher emulsion height than those with LMP and Ca, indicating Ca was not that critical for storage stability when LMP was present. Besides, LMP emulsions (Figure 1C) seem to be more stable with lower phase separation for both CO and MO than the emulsions formed with S-AA and S-CA (Figure 1A, B). For most emulsions, lower phase separation was observed with MO than CO, indicating higher emulsion stability with the MO, which followed the observation by Ghosh et al. (2011).