Table 2 Variables and their levels in the central composite design
Factors: independent variables | Level Used | |
|---|---|---|
X1 = Gum content (%) | 0 | 2 |
X2 = surfactant content (%) | 0.25 | 2 |
X3 = Storage period (days) | 0 | 50 |
Responses | ||
Z-average (nm) | Min. | |
PDI | Min. | |
Zeta-potential (mV) | Min. | |
Creaming index (%) | Min. | |
Interfacial tension (mN/m) | Min. | |
Encapsulation efficiency of primary emulsion (%) | Max. | |
Encapsulation efficiency of double emulsion (%) | Max. | |