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

摘要

Cyclodextrin (CD) complexation procedures are relatively simple processes, but these techniques often require very specific conditions for each individual guest molecule. Variations of the coprecipi-tation from aqueous solution technique were optimized for the CD complexation of the natural antioxidants α-tocopherol and quercetin. Solid inclusion complex products of α-tocopherol/ β-CD and quercetin/γ-CD had molar ratios of 1.7:1, which were equivalent to 18.1% (w/w) α-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 α-tocopherol/β-CD and quercetin/γ-CD complexes from their individual reactants were calculated as 24 and 21% (w/w), respectively. ATR/FT-IR, ~(13)C 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.