Microwave-assisted extraction of antioxidant phenolic compounds from artichoke (Cynara scolymus L. cv Bayrampasa): optimisation and kinetic modelling

Abstract

The objective of the present work was to optimise an efficient alternative technique for the extraction of total phenolics and antioxidants from Bayrampasa variety artichoke by-products, and to evaluate the potential role of artichoke as a source of health-promoting phenolic compounds and antioxidants. In the present work, microwave-assisted extraction (MAE) was used in order to obtain phenolic compounds and antioxidants from artichoke by-products such as leaves and bracts. The obtained phenolic compounds and antioxidants were assessed in terms of total phenolic content (TPC), 2,2-diphenyl-1-picryl-hydrazine (DPPH) antioxidant activity, and cupric-reducing antioxidant capacity (CUPRAC). The highest TPC and CUPRAC values were obtained at 4 min, and the highest DPPH activity was observed at 6 min and 80°C for leaf and bract extracts; also, the TPC, DPPH, and CUPRAC values of bract extracts were significantly lower than that of leaf extracts. Modelling of MAE for the artichoke leaves and bracts mixture using the central composite design was examined for determination of solvent/solid ratio (v/w), time, and solvent/water ratio (v/v). Additionally, second order and Peleg’s kinetic models proved to be the most suitable in describing the MAE kinetics for artichoke leaves and bracts mixture.