Optimization of homogenization-evaporation process for lycopene nanoemulsion production and its beverage applications

Lycopene is a natural antioxidant which has several health benefits. Undesirable oxidation of lycopene compromises its health benefits and also affects the sensory quality of food products containing lycopene. Health benefits associated with lycopene in food preparations can be enhanced by preventing its degradation by incorporating it into the oil phase of an oil-in-water nanoemulsion. In this study, lycopene nanoemulsions were prepared from a low-concentration lycopene extract using an emulsification-evaporation technique. The effects of the concentrations of the lycopene extract (0.015 to 0.085 mg/mL) and emulsifier (0.3 to 0.7 mg/mL), and the number of homogenization cycles (2 to 4) on the droplet size, emulsification efficiency (EE), and nanoemulsion stability were investigated and optimized by statistical analysis using a Box-Behnken design. Regression analysis was used to determine the 2nd-order polynomial model relationship of independent and dependent variables, with multiple regression coefficients (R(2)) of 0.924, 0.933, and 0.872, for the droplet size, EE, and nanoemulsion stability, respectively. Analysis of variance showed that the lycopene extract concentration has the most significant effect on all the response variables. Response surface methodology predicted that a formulation containing 0.085 mg/mL of lycopene extract and 0.7 mg/mL of emulsifier, subjected to 3 homogenization cycles, is optimal for achieving the smallest droplet size, greatest emulsion stability, and acceptable EE. The observed responses were in agreement with the predicted values of the optimized formulation. This study provided important information about the statistical design of lycopene nanoemulsion preparation.