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Oregano (Origanum vulgare) leaf polyphenols show high antioxidative properties. However, their low stability to external conditions like temperature, light, pH and moisture require an efficient encapsulation for bioactive preservation, shelf-life extension and sustained release. This work aimed at encapsulating the sensitive polyphenols obtained from oregano leaves by freeze drying technique, using a combination of reconstituted aloe vera hydrogel as the base material, with maltodextrin and gum Arabic as coating materials. The encapsulation efficiency (85.11 ± 1.15 to 95.60 ± 0.17%) showed good retention of polyphenols by freeze drying method. The microparticles were further characterized on color, moisture content, water activity, solubility, flowability, cohesiveness, morphological analysis and in-vitro release. The powder gave good flowability, less cohesiveness and good reconstitution properties, making it suitable for food applications. Sustained release was obtained at low temperature (15 °C) and low pH (2 and 5) conditions (upto 50% release for a time of 120 min). among the various mathematical models used, Korsmeyer-Peppas model (R2 = 0.96–0.99) was the best fit one, followed by Higuchi model (R2 = 0.94–0.99), which were suitable for simulating intestinal phase release. The polyphenol release occurred through diffusion, obeying Fick's law of molecular diffusion.
Rout et al. (Fri,) studied this question.