Abstract: In this work, equivalent surface analysis was used to evaluate the synergistic effect of a new antioxidant formula containing ferulic acid, phloretin and soluble vitamin E on DPPH radical scavenging activity, Fe3+ reducing power and ABTS radical scavenging activity. The results indicated different mixing ratios of the antioxidant factors exhibited a synergistic, antagonistic, or additive effect to some extent. In this study, response surface methodology (RSM) was adopted for optimizing the formulation of the antioxidant factors to achieve the highest OD (overall desirability) value. The optimal formulation consisted of 34.9% ferulic acid, 35.1% phloretin and 30% soluble vitamin E.

Key words: ferulic acid, phloretin, soluble vitamin E, antioxidant, equivalent surface analysis, RSM