Assessing release kinetics and dissolution of spray-dried Roselle (Hibiscus sabdariffa L.) extract encapsulated with different carrier agents

- The aim was to investigate the effect of some carriers on Roselle's extract release.
- All the particles obtained followed a Weibull-First Order kinetic model.
- Pectin retained the highest amount of polyphenols after the drying process.
- Pectin released the highest amount of phenolic compounds during a longer time.
- Estimated dissolution times proved to be more reliable than the observation method.

The aim of this study was to investigate the effect of different carriers (maltodextrin, pectin, gelatin, carboxymethyl cellulose, whey protein, carrageenan and gum arabic) on the release kinetics and dissolution of Roselle's extract obtained through a spray drying process. Aqueous solutions at different concentrations of carrier and extract were prepared. The particles obtained exhibited nearly mono-modal or bimodal size distribution, indicating two predominant sizes. The frequency distribution of the mean size of the powders behaved, significantly, like a normal distribution. Throughout the dissolution test, all the particles obtained followed a Weibull-First Order kinetic model. Pectin retained the highest amount of polyphenols after the drying process (98.20 mg GAE/100 mg GAE of roselle concentrate) and released the highest amount of phenolic compounds (79.48 mg GAE/100 mg GAE in the particles) during a longer time. Pectin particles obtained (9 μm as mean size) were significantly homogeneous (93.45 g/100 g powder), being the most suitable carrier of Roselle's phenolic compounds compared to the other carriers used. Estimated dissolution times, by means of the dissolution equation proposed, were compared to experimental results and proved to be more reliable than the regularly used observation method.