Fig. 3 presents a Pareto chart showing the influence of each investigated factor on the response, as well as the possible cross effects among these factors. The results, considering the relative area of isoorientin as response, demonstrated that the effects of the type ofsolvent and percentage of the solvent in water are significant factors. On the other hand, the extraction time is not a relevant factor in the range considered. Moreover, the negative value of the effect for the proportion of solvent (−0.538) indicates that a proportion of 60% is more efficient for extraction, and the factor type of solvent showed a strong positive effect (0.632). Furthermore, the 1 by 2 interaction (type and proportion of solvent) was found to be statistically significant (pb0.05), demonstrating that ethanol 60% provided a higher extraction of isoorientin. This analysis can be confirmed by the response surface, plotting type versus proportion of solvent (Fig. 4): the response surface shows the optimal level for each variable, and the highest response in the flavonoid extraction of the passion fruit was obtained with solvent ethanol 60% and 1.5 min of sonication.