Table 1.
Range of the independent variables values in the sequential experimental design strategy.
Table 2.
Responses obtained in the 24-1 fractional factorial experimental design and triplicate at the central points to calculate the average, standard deviation and relative standard deviation.
Table 3.
Effect (± standard error) of the independent variables on the density difference between the mucilage and the oil+SAIB (Δρ), the ratio between the surface tension of the emulsion and of the mucilage (γ emulsion/ γ mucilage), the ζ, particle size, viscosity and ratio between the viscosities of the mucilage and of the oil+SAIB (η mucilage/ η oil), amount of oil released and the stability of the emulsion after 15 days, in the 24-1 fractional factorial design.
Table 4.
Responses obtained in the two-level full-factorial experimental design to evaluate the effects of starch and Arabic gum concentrations.
Table 5.
Effect (± standard error) of the independent variables on the ratio between the surface tension of the emulsion and of the mucilage (γ emulsion/ γ mucilage), ζ, particle size, viscosity, ratio between the viscosity of the mucilage and of the oil+SAIB (η mucilage/ η oil), amount of oil released and stability of the emulsion after 15 days, in the full-factorial experimental design.
Fig 1.
Response surface obtained from the model for stability after 15 days (%) (= 83.6 + 9.0 x1 + 13.0 x2 - 12,0 x1 x2, where x1 and x2 are the normalized values of starch and Arabic gum concentrations).
Table 6.
Experimental data and predicted by the model for stability after 15 days (%), for the viscosity of the emulsions at a shear rate of 1000 1/s and for the emulsion/mucilage surface tension ratio.
Fig 2.
Results for viscosity of the emulsions at a shear rate of 1000 1/s (cP).
(a) Response surface obtained from the model for cP (= 173.6 + 124.0 x1 + 126.5 x2 + 69.5 x1 x2, where x1 and x2 are the normalized values of starch and Arabic gum concentrations). (b) Viscosity curve versus stability after 15 days.
Fig 3.
Results for emulsion/mucilage surface tension ratio.
(a) Response surface obtained from the model for γ emulsion/ γ mucilage (= 1.200 + 0.291 x1 + 0.197 x2, where x1 and x2 are the normalized values of starch and Arabic gum concentrations). (b) Curve of the emulsion/mucilage surface tension ratio versus stability after 15 days.