Aronia leaves at the end of harvest season - Promising source of phenolic compounds, macro- and microelements

Aronia (Aronia melanocarpa) leaves at the end of harvest season (in the leaves senescence vegetative stage), when it represents an agricultural waste material, have been extracted under different conditions in order to assess potential of this plant material in valuable bioactive compounds recovering. Response surface methodology was used in screening of the most important parameters effecting extraction (ethanol concentration, extraction time and solvomodule), as well as for mathematical modeling and process optimization. The optimal extraction conditions (ethanol concentration of 49.18%, extraction time of 75.26 min and solvomodule of 0.19 g/mL) that simultaneously maximize extractive matter yield and total phenolic content, minimizing the EC50 value, were proposed by desirability function approach. Finally, in further assessment of aronia agricultural waste as a potential source of bioactive compounds, the extract obtained under proposed optimal conditions was analyzed by UHPLC-MS, while the content of macro- and microelements was determined by ICP-OES technique.