The stability of nanoemulsions to temperature (30–90 C), pH (2–10) and ionic strength (0–500 mM NaCl or 0–90 mM CaCl2) was also tested.
Tween 20 nanoemulsions were unstable to heat treatment at 90 C for 15 min. WPI-stabilised nanoemulsions
exhibited droplet aggregation near the isoelectric point at pH 4.5 and 5 and they were also
unstable at salt concentration above 30 mM CaCl2. These results indicated that stable nanoemulsions
can be prepared by careful selection of emulsifiers.