Résumé:
Response surface methodology in combination with a Box-Behnken experimental design was
performed to optimize the extraction conditions, resulting in a maximum yield for the total
phenolic content (TPC) from leaves of Pistacia atlantica. The ranges of the examined
independent variables (factors), i.e. the extraction time (24-72 hours), liquid-to-solid ratio
(30:1-50:1 ml solvent per g dry leaf) and extraction temperature (35-55°C) were identified by
preliminary experiments. Quadratic polynomial regression models were fitted through the
experimental results. They showed acceptable coefficients of multiple determination. From
the models, the liquid-to-solid ratio was found to have the most influence on the extraction of
TPC. The optimum extraction conditions were found at 72 h extraction time and 50:1 ml/g
liquid-to-solid ratio. For the extraction temperature, rather high values (about 50°C) were
found best. Using the optimized conditions, the TPC varied from 256 to 306 mg gallic acid
equivalents g dry leaf in different sample types.
