The response surface obtained by central composite design is illustrated in Fig. 4. The values optimized according to the response surface were 54 °C for temperature and 60 min for the extraction time. However, the optimum extraction time was outside the upper limit (44 min) of experimental set domain. Then, in order to evaluate the analytical response of the optimum conditions for the response surface methodology, experiments were carried out in the temperature and extraction time values shown in Table 3.