Extraction of selected minerals from Melissa officinalis L. leaves by using two-level factorial design

In this study, a two-level factorial design was used to evaluate the significant extraction parameters in achieving higher recovery yield of Cu, Fe, Mn, and Zn contents from Melissa officinalis leaves. The independent parameters were solid-to-solvent ratio, extraction temperature, and duration of extraction. The experimental data obtained were fitted to a first-order polynomial equation using multiple regression analysis and studied by appropriate statistical methods (ANOVA). The optimum extraction conditions were as follows: solid-to-solvent ratio 1:15 g/mL, extraction temperature 100°C, and extraction time 80 min. Under these conditions, the experimental concentrations were in close agreement with the value predicted by the model. The correlation coefficients of 0.9947, 0.9966, 0.9939, and 0.9957 observed between the predicted and actual values for the response variables are evidence that the regression model can represent the experimental data well. Minerals present in the extracts may be maximized when process conditions are carefully adjusted within the reported values.