Optimized Preparation of Spray-dried Anthocyanins Microcapsules

  Objective  TPreparation of an spray-dried encapsulated anthocyanins from Hibiscus sabdariffa was optimized.

  Method   Single factor experiment and response surface method were employed for the process optimization. Structure of the microcapsules was characterized with scanning electron microscopy (SEM). Product stability under exposure of light, heat, and metal ions was determined.

  Results   The optimum encapsulation used 7% total solids that consisted of 70% maltodextrin, 3% gum Arabic, and 7% H. sabdariffa anthocyanin, and the dehydration applied a spray-drying inlet-air temperature at 143 ℃. The resulting encapsulation rate reached 97.11%. Observed under SEM, the spherical microcapsules were smooth on the surface with no cracks or voids. Exposed to temperature or light, the microcapsules were significantly more stable than the purified anthocyanins. And, the product stability in the presence of Cu²⁺ or Zn²⁺ was also significantly improved by the process. A maximum shelf life of the product could be achieved by storing it at 4 ℃ in darkness and avoiding direct contact with Cu²⁺ or Zn²⁺.

  Conclusion   H. sabdariffa anthocyanin microcapsules with a significantly improved shelf life were successfully prepared by the optimized microencapsulation and spray-drying.