The characterization and evaluation of the synthesis of large-ring cyclodextrins (CD9–CD22) and α-tocopherol with enhanced thermal stability

Abstract

Large-ring cyclodextrins LR-CDs (CD₉–CD₂₂) were obtained from rice starch using cyclodextrin glycosyltransferase (CGTase), and were used as a wall material for embedding α-tocopherol. Complexes of α-tocopherol and LR-CDs were prepared by co-precipitation. A molar ratio of α-tocopherol/LR-CD of 1 : 2 showed the highest encapsulation efficiency. The surface morphology of the complex particles was observed to vary from irregular flakes to the formation of smaller clusters of particles using scanning electron microscopy (SEM). Based on ¹H NMR and FT-IR observations, the inclusion complexes exhibited significant chemical shifts of 0.3 ppm and decreased peak signals. In addition, thermal analysis showed that the microcapsules improved the thermostability of the α-tocopherols. Antioxidant activity analysis proved the stability of α-tocopherol during storage. This study could serve as a reference for the more effective use of LR-CDs as wall materials.