Effect of Processing on Physicochemical Characteristics and Bioefficacy of β-Lactoglobulin-Epigallocatechin-3-gallate Complexes

Varying amounts of epigallocatechin-3-gallate (EGCG) were encapsulated in beta-lactoglobulin (beta-Lg) nanoparticles, either native or processed, denoted as heated or desolvated protein. The stability, physical properties, and bioactivity of the beta-Lg EGCG complexes were tested. Native beta-Lg EGCG complexes showed comparable stability and binding efficacy (EGCG/beta-Lg molar ratio of 1:1) to heated beta-Lg nanoparticles (1% and 5% protein w/w). The sizes of heated and desolvated beta-Lg nanoparticles were comparable, but the latter showed the highest binding affinity for EGCG. The presence of EGCG complexed with beta-Lg did not affect the interfacial tension of the protein when tested at the soy oil-water interface but caused a decrease in dilational elasticity. All beta-Lg complexes (native, heated, or desolvated) showed a decrease in cellular proliferation similar to that of free ECGC. In summary, protein EGCG complexes did not alter the bioefficacy of EGCG and contributed to increased stability with storage, demonstrating the potential benefits of nanoencapsulation.