Protein oxidation affected the encapsulation properties of rice bran protein fibril-high internal phase pickering emulsions: Enhanced stability and bioaccessibility of β-carotene

Rice bran protein fibril (RBPF)-high internal phase Pickering emulsions (HIPPEs) loaded with beta-carotene (CE) were constructed to enhance stability and bioavailability of CE. Rice bran (RB) protein with varying oxidation degrees was extracted from RB with varying storage period (0-10 days) to prepare RBPF by acid-heating (90 degrees C, 2-12 h) to stabilize HIPPEs. The influence of protein oxidation on the encapsulation properties of RBPF-HIPPEs was studied. The results showed that CE-HIPPEs could be stably stored for 56 days at 25 degrees C. When RB storage time was the same, the average particle size, lipid hydroperoxide content, and malondialdehyde content of CEHIPPEs and the CE degradation rate initially fell, and then grew as the acid-heating time prolonged, while the zeta-potential value, viscosity, viscoelasticity, free fatty acid (FFA) release rate, and bioaccessibility first rose, and subsequently fell. When acid-heating time of RBPF was the same, the average particle size, lipid hydroperoxide content, and malondialdehyde content of CE-HIPPEs initially fell, and subsequently increased with RB storage time extended, while the zeta-potential value, viscosity, viscoelasticity, FFA release rate, and bioaccessibility initially increased, and then decreased. Overall, Moderate oxidation and moderate acid-heating enhanced the stability as well as rheological properties of CE-HIPPEs, thus improving the stability and bioaccessibility of CE. This study offered a new insight into the delivery of bioactive substances by protein fibril aggregates-based HIPPEs.