Stability study of α-toc/β-CD powders obtained by microwave heating and encapsulation process

Abstract

The α-tocopherol (α-toc) degrades faster than both γ- and δ-toc; its degradation rate is 10 times faster than δ-toc. The foremost factors that could affect the stability of vitamins upon storage are light, oxygen, and heat. Thus, this study aimed to investigate the thermal, storage, and physical stability of the α-tocopherol/β-cyclodextrin (α-toc/β-CD) powder obtained via microwave heating and encapsulation process. DSC, TG, and DTG were performed for thermal stability characterizations, while storage study was performed to investigate the stability of the encapsulated and non-encapsulated α-toc stored at 5, 28, and 50 °C for 42 days. The results obtained were then fitted with first-order degradation kinetic model to obtain the half-life for each sample. The physical stability in terms of flowability and compressibility was also studied during the storage. Encapsulation of α-toc into β-CD has successfully increased the thermal stability of α-toc to a higher decomposition temperature from 280 to 300 °C. The storage study showed that the encapsulation of α-toc by β-CD using the microwave technique has successfully improved the shelf life of α-toc with the half-life of 990, 523 and 126 days for samples stored at 5, 28, and 50 °C, respectively, with a good flow powder characteristics except for powder stored at 50 °C which showed passable flow powder characteristics after 42 days of storage.