Self-assembly of glycinin nanoparticles for delivery of phenolic compounds from Phyllanthus urinaria

The purpose of this work was to fabricate and evaluate glycinin nanoparticles for delivery of phenolic compounds from Phyllanthus urinaria. The nanoparticles were prepared using self-assembly method, and three variables, including pH (X1), glycinin concentration (X2) and glycinin to phenolic compounds mass ratio (X3) for the achievement of high encapsulation efficiency of phenolic compounds, were optimized using response surface methodology. The statistical analyses show that the independent variables (X1, X2) and the quadratic terms (X12, X22 and X32) have significant effect on the encapsulation efficiency. The optimized conditions are X1 of 4.4, X2 of 3.2 mg mL−1, and X3 of 6.2 : 1. Under these conditions, the experimental value is 51.42% (n = 3), which is well matched with the predicted value. Scanning electron microscopy (SEM) micrograph and dynamic light scattering (DLS) analyses show that the nanoparticles have an approximately spherical morphology with a smooth surface, and the mean particle size was about 100 nm with a narrow size distribution of 0.318. The release of phenolic compounds shows a faster release at pH 7.4 but a lower release at pH 1.2, and the release mechanism at pH 1.2 and 7.4 is Fickian diffusion and anomalous transport, respectively.