order to optimize the preparation process conditions of phosphorelated peanut protein isolate - polypeptide films, experiment was carried out with the response surface Box-Benhnken experiment, on the basis of single factor experiments. The results showed that the optimum conditions obtained were protein concentration, pH value, glycerol percentage content of protein, xanthan gum percentage content of protein, time, temperature, ultrasonic power, ultrasonic frequency, polypeptide concentration of 8%, 8.2, 13.4%, 1%, 60min, 69℃, 270w, 28kHz, 61mg/mL, respectively. Under the optimum conditions, the theoretical predictive values of film thickness, water absorption and light transmittance were 86μm, 41.9% and 53.6%, respectively. The results of verification experiment showed that film thickness, water absorption rate and light transmittance rate could reach 88±2μm, 43.1±1.2% and 52.4±1.5%, respectively. The differences between experimental and theoretical values were 2.33%, 2.86% and 2.24%, respectively. This suggested the response surface quadratic model fitted well. The functional properties were better than those of phosphorelated modified peanut protein isolate films, and these functional properties included tensile strength of 9.62 MPa, elongation of 101.68 %, solubility of 47.69 %, water vapor permeability of 6.95 g•(m2·h)-1 and antioxidant activities including DPPH free radical scavenging activity of IC50 7.70 mg·mL-1, hydroxy free radical scavenging activity of IC50 5.98 mg·mL-1, superoxide anion free radical scavenging activity of IC50 4.20 mg·mL-1, iron ion chelating activity of IC50 3.79 mg·mL-1, copper ion chelating activity of IC50 13.61 mg·mL-1, lipid peroxidation inhibition activity of IC50 8.62 mg·mL-1, iron reducing power of IC50 13.93 mg·mL-1, molybdenum reducing power of IC50 5.49 mg·mL-1 of phosphorelated peanut protein isolate - polypeptide films. The results of this study provided a new way for the application of phosphorelated peanut protein isolate.
