Optimization of Berberine Extraction Conditions from Seedless Barberry and Microencapsulation of the Extract using Complex Coacervation and Gelatin/ Tragacanth (Astragalus rahensis)

Background and Objectives: Berberis vulgaris, an Iranian native plant, includes valuable compounds such as berberine with therapeutic, health-promoting and nutritional effects. However, major parts of this plant are discarded as wastes. The major aims of this study were optimization of berberine extraction conditions from the whole plant with maximum antioxidant activity, the extract microencapsulation using complex coacervation and two biopolymer gelatin/flake tragacanth (Astragalus rahensis) and analysis of the physical characteristics of the moist microcapsules.  Materials & Methods: Berberine extraction was optimized using response surface methodology based on three extraction parameters of time, temperature and solvent:water ratio at three levels and five central points. The berberine concentration was analyzed using high-performance liquid chromatography and its antioxidant activity was studied to investigate the optimized conditions. The optimum extract was microencapsulated using complex coacervation and gelatin/tragacanth with three ratios of 1:1, 2:1 and 1:2 w/w. Furthermore, yield, efficiency, particle size, solubility and the microstructural and release characteristics of the wet microcapsules were characterized. Results: Optimized extraction conditions with 0.88 desirability included 0.5 h, 22.9 °C and 75% solvent:water ratio. The average surface size of the microcapsules was in the range of 71.31–90.15 μm. Samples with 2:1 ratio indicateds the maximum yield 95.1 and sample with 2:1 ratio showed the maximum solubility of 10%. Efficiency in all samples were similarly 96% ±1. Conclusion: Complex coacervation using gelatin/tragacanth with a ratio of 1:2 was developed to produce wet microcapsules of the optimum extract of berberine with the highest yield and efficiency and low solubility as well as particle sizes of smaller than 100 μm.