Encapsulation of β-carotene in high internal phase Pickering emulsions stabilized by soy protein isolate - epigallocatechin-3-gallate covalent composite microgel particles

In the current study, soy protein isolate (SPI) and epigallocatechin-3-gallate (EGCG) covalent composite microgel particles with antioxidant capacity were prepared and the particles was used as beta-carotene-loaded high internal phase Pickering emulsions (HIPPEs) stabilizers. The covalent binding of SPI-EGCG altered the structures of the SPI through an unfolding of the polypeptide chain. Moreover, compared to HIPPEs stabilized by SPI alone, HIPPEs stabilized by SPI-EGCG microgel particles showed smaller particle size, higher apparent viscosity, and better stability. Microstructure of the fabricated HIPPEs results revealed that SPI-EGCG covalent conjugates promoted the formation of a thick and dense protective layer on the surfaces of oil droplets. Furthermore, beta-carotene-loaded HIPPEs stabilized by SPI-2% EGCG microgel particles exhibited a higher retention rate after 42 days of storage and better bioaccessibility (86.6 4 +/- 0.27% and 54.43 +/- 0.50%, respectively) compared to HIPPEs stabilized by SPI (75.80 +/- 0.49% and 38. 31 +/- 0.93%, respectively). The current study illustrated that the design of HIPPEs stabilized with protein-polyphenol composite particles were of great importance for the delivery of lipophilic bioactive compounds. (C) 2022 Elsevier B.V. All rights reserved.