Cyclodextrin Inclusion Complex Formation and Solid-State Characterization of the Natural Antioxidants α-Tocopherol and Quercetin

Abstract

Cyclodextrin (CD) complexation procedures are relatively simple processes, but these techniques often require very specific conditions for each individual guest molecule. Variations of the coprecipitation from aqueous solution technique were optimized for the CD complexation of the natural antioxidants alpha-tocopherol and quercetin. Solid inclusion complex products of alpha-tocopherol/beta-CD and quercetin/gamma-CD had molar ratios of 1.7:1, which were equivalent to 18.1% (w/w) alpha-tocopherol and 13.0% (w/w) quercetin. The molar reactant ratios of CD/antioxidant were optimized at 8:1 to improve the yield of complexation. The product yields of alpha-tocopherol/beta-CD and quercetin/gamma-CD complexes from their individual reactants were calculated as 24 and 21% (w/w), respectively. ATR/FT-IR, 13C CP/MAS NMR, TGA, and DSC provided evidence of antioxidant interaction with CD at the molecular level, which indicated true CD inclusion complexation in the solid state. Natural antioxidant/CD inclusion complexes may serve as novel additives in controlled-release active packaging to extend the oxidative stability of foods.

Effect of hydroxypropyl-β-cyclodextrin complexation on the aqueous solubility, structure, thermal stability, antioxidant activity, and tyrosinase inhibition of paeonol

“…HP-b-CD in the PAE-HP-b-CD complex destroyed the interaction of PAE molecules to form a crystalline structure). These DSC results confirmed that PAE was no longer present as a crystalline material and its HP-b-CD solid complexes were present in the amorphous state because an HP-b-CD molecule encapsulated each PAE molecule [28].…”

“…Figure 3a, b and c present the H-NMR spectra of PAE, HPb-CD and PAE-HP-b-CD complex, respectively. The proton resonances of HP-b-CD were assigned based on the relevant literature [25][26][27][28]: chemical shifts in the range 3.85-3.95 ppm were those of H3 and H8, those in the range 3.40-3.75 ppm were those of H2, H4 and H7, and those in the range 3.70-3.85 ppm were those of H5 and H6. The appearance of chemical shifts at 5.51, 6.65 and 7.84 ppm in Fig.…”

Butter cholesterol removal using different complexation methods with beta-cyclodextrin, and the contribution of photoacoustic spectroscopy to the evaluation of the complex

“…CD complexation procedures are relatively simple processes, but these techniques often require very specific conditions for each individual guest molecule (Koontz, Marcy, O'Keefe, & Duncan, 2009). Variations of the techniques have been used to form CD complexes.…”

“…These tools have been shown to be efficient to provide information about the interactions between the guest and the CD hosts, at the molecular level (Koontz, Marcy, O'Keefe & Duncan, 2009). Although it is not yet a routine method, photoacoustic spectroscopy of solids (PAS) has been shown to be a valuable technique for spectroscopic investigation of solid and semisolid matter.…”

Short Overview of Encapsulation Technologies for Delivery of Bioactives to Food

“…However, the procedure of encapsulation, as well as conditions necessary to achieve the complexation are different and unique for each and every guest molecule, i.e. bioactive compound to be encapsulated [54]. Usually, it is required to stir, sonicate or heat the mixture of CDs solution and bioactives in order for complexation to occur [55,56].…”