Physicochemical properties, antioxidant action and practical application in fresh cheese of the solid inclusion compound γ-cyclodextrin•quercetin, in comparison with β-cyclodextrin•quercetin

Quercetin is an antioxidant flavonol very sensible to light and oxidants that can benefit from stabilisation by encapsulation into cyclodextrins. In this work we study the solid inclusion compounds of quercetin with beta- and gamma-cyclodextrins (beta-CD and gamma-CD) obtained by freeze-drying. Combined results from microanalysis, FT-IR, powder X-ray diffraction, C-13{H-1} CP/MAS NMR spectroscopy and thermogravimetry demonstrating that gamma-CD, having a larger cavity, is the most adequate host to form a stable inclusion complex with quercetin. The anti-peroxidation capacity of the compounds was determined and followed the order beta-CD center dot quercetin >> quercetin > gamma-CD center dot quercetin. Both gamma-CD center dot quercetin and beta-CD center dot quercetin are able to inhibit DPPH radicals at a rate three times faster than pure quercetin, but their EC50 is higher (50 mu M vs 17 mu M for quercetin). The practical applicability of the two CD center dot quercetin adducts as nutraceutical additives in fresh cheese was established. Fortified fresh cheese had a firmer texture and yellowish colour, but no significant changes in the overall sensorial qualities were found by a panel of non-trained tasters when compared with the control (non-treated fresh cheese). (C) 2017 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.