Modeling and Optimization of process conditions in nanoencapsulation of the polyphenolic extract of industrial apple pomace

In present study, the process conditions for nanoencapsulation of rich polyphenolic extract of apple pomace by solvent displacement method were optimized using response surface methodology (RSM). The independent variables were expressed as wall to core ratio, surfactant w/w% and ultrasonic mixing time (min). The response (or dependent variable) was the antioxidant activity of polyphenols still remained in supernatant after nanocapsuls isolation (expressed as DPPH %), which was also optimized. The optimum conditions were: the wall to the core ratio (5.5), the percentage of the surfactant (5 %w/v), and homogenization time (2 min). The analysis of variance for response showed that relatively all independent variables are significant (p< 0.05) at the 95% confidence level. The results indicated that the shell to core (X1) followed by the percentage of surfactant (X2) are the significant factors affecting the response. In addition the coefficients of the determinations (R2 =0.922) and the good agreements between the predicted values with the experimental values for dependent variable, were another indication that the model adequately fit the chosen parameters in their ranges. In optimal condition, the particle size (measured by DLS and SEM) was in the range of 50-70 nm and polyphenol loading efficiency was about 98%.