Exploitation of artichoke byproducts to obtain bioactive extracts enriched in inositols and caffeoylquinic acids by Microwave Assisted Extraction

Byproducts from artichoke represent the majority of the mass collected from the plant and constitute an interesting source of bioactive compounds such as inositols and caffeoylquinic acids. In this work, a microwave assisted extraction (MAE) methodology was developed for the simultaneous extraction of these compounds from artichoke stalks, leaves, receptacles and external bracts. Optimal MAE conditions to maximize the extraction of these bioactives and the antioxidant activity were 97 degrees C, 3 min, ethanol:water (50:50, v/v). Moreover, a GC-MS methodology was also developed for the simultaneous determination of these compounds in a single run; optimal derivatization conditions were achieved using hexamethyldisilazane and N,O-bis(trimethylsilyl)trifluoroacetamide with 1% trimethylchlorosilane. Artichoke receptacle extracts were the richest in caffeoylquinic acids (28-35 mg g(-1) dry sample), followed by the bracts (9-18 mg g(-1) dry sample), while those from leaves showed the highest concentrations of inositols (up to 15 mg g(-1) dry sample). Receptacle extracts also had the highest antioxidant activity (123 mg TE g(-1) dry sample) and the greatest concentration of total phenolic compounds (47 mg GAE g(-1) dry sample). Therefore, the developed methodology could be considered as a valuable procedure to obtain and characterize bioactive ingredients with industrial interest from artichoke byproducts, opening new routes of revalorization of artichoke agro-industrial residues. (C) 2019 Elsevier B.V. All rights reserved.