Encapsulation of (-)-epigallocatechin-gallate (EGCG) in hordein nanoparticles

(-)-epigallocatechin-gallate (EGCG), a biologically active compound in green tea, has been found to have antimicrobial, anti-carcinogenic, and anti-oxidative activities, but it can easily be degraded when exposed to light and high temperature. A liquid-liquid dispersion method was used to prepare EGCG-hordein nanoparticles to better protect EGCG from degradation. The effects of different processing variables on the storage stability and interaction mechanisms between EGCG and hordein from those nanoparticles were investigated. Results showed that the solution pH was the most significant processing factor in terms of determining the stability of EGCG-hordein nanoparticles. Specifically, the EGCG-hordein nanoparticles showed an average particle size of 160 +/- 10 nm, Zeta potential of 20.7 +/- 0.4 mV, encapsulation efficiency of 91.2%, and loading efficiency of 15.2%. EGCG-hordein nanoparticles had better storage stability at 4 degrees C. The fluorescence quenching mechanism between EGCG and hordein was found to be due to static quenching and Forster non-radiative energy transfer.