3.2. Parameter optimization by experimental design
The parameters effects, as well as their interactions effect were
estimated by the realization of a Doehlert experimental design
using grape seeds tannins G15ox (0.3% (w/v), phosphate buffer
75 mM). Three main phenomena were observed: (i) At pH 3–4, a
separation of phases was observed immediately after sonication,
without the formation of emulsion. (ii) Emulsions were obtained
when the pH was equal or higher than 5. (iii) For pH 8–9, creaming
started only 72 h after emulsification. Emulsions prepared at these
pHs were the most stable.