Cyclodextrins as high-performance green co-solvents in the aqueous extraction of polyphenols and anthocyanin pigments from solid onion waste
Date
2021Language
en
Keyword
Abstract
This investigation was carried out with the scope to examine three commonly used cyclodextrins (CDs), β-cyclodextrin (β-CD), methyl β-cyclodextrin (m-β-CD) and 2-hydroxypropyl β-cyclodextrin (HP-β-CD) as green co-solvents for the effective extraction of polyphenols and pigment from onion solid wastes (OSW). Efficiency appraisal was based on the “extraction efficiency index” (Iee), a parameter established to readily assess the ability of a CD to boost aqueous polyphenol extraction. m-β-CD was found to be the most efficient, giving Iee of 3.39 and 0.073 mg μmolCD−1 for total polyphenols and total pigments, respectively. Response surface optimization revealed that both m-β-CD and HP-β-CD required almost identical time and temperature conditions for maximized polyphenol recovery, but major differences were found for pigment extraction. β-CD was the least efficient in extracting total polyphenols, but it displayed a satisfactory effectiveness in pigment extraction. The antiradical activity and ferric-reducing power of the extracts generated with m-β-CD and HP-β-CD were comparable to those of hydroethanolic and hydroglycerolic extracts. Both these CDs were also more efficient than β-CD in extracting spiraeoside and quercetin, but β-CD exhibited higher efficiency for anthocyanin extraction. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.