Optimisation of conditions for the preparation of β-carotene nanoemulsions using response surface methodology

Response surface methodology (RSM) was used to optimise the conditions for preparing β-carotene nanoemulsions. The effects of β-carotene (0.2–1.8%, w/w) and emulsifier (6.9–13.1%, w/w) concentrations, the homogenization pressure (79.1–140.9 MPa) and temperature (34.5–65.5 °C) on the particle size and stability of the nanoemulsions were studied. Results showed that the experimental data could be adequately fitted into a second-order polynomial model with multiple regression coefficients (R2)(R2) of 0.921 and 0.981 for the particle size and stability, respectively. Homogenization pressure and β-carotene concentration and the quadrics of β-carotene concentration (P<0.05)(P<0.05) had a significant effect on the particle size of the nanoemulsions. Homogenization temperature and pressure, β-carotene concentration, the quadrics of emulsifier concentration and the interactions between β-carotene and emulsifier concentrations and between homogenization temperature and emulsifier concentration (P<0.05)(P<0.05) had a significant effect on the stability of the emulsions. The optimum conditions for preparing β-carotene nanoemulsions were predicted to be: homogenization pressure, 129 MPa; homogenization temperature, 47 °C; β-carotene concentration, 0.82%; emulsifier concentration, 8.2%.