Abstract: The stability of β-carotene emulsion in orange juice was evaluated under different preparation conditions and different storage temperatures. The effects of homogenization pressure, vitamin C concentration, arabic gum concentration and sterilization time on the stability of β-carotene emulsion in orange juice were monitored based on the changes in particle size and migration rate of β-carotene emulsion droplets during the first two hours and β-carotene content during two-week storage. The results showed that the best stability for β-carotene emulsion in orange juice was achieved under the conditions: homogenization pressure of 30 MPa, vitamin C concentration of 0.03%, Arabic gum concentration of 0.08% and sterilization time of 7 min. The stability of β-carotene emulsion in orange juice was also investigated at different storage temperatures. We found that β-carotene degradation could be fitted into a first-order kinetic model with a regression coefficient (R2) of 0.992. The logarithm of degradation rate constant against the reciprocal of absolute temperature revealed the best fit to the Arrhenius model with a regression coefficient (R2) of 0.961.

Key words: orange juice, β-carotene emulsion, stability, first-order kinetic model