Epigallocatechin-3-gallate improved rheological properties of rice bran protein-soybean protein isolate conjugates emulsions by regulating interface protein conformation

Abstract

The effects of epigallocatechin-3-gallate (EGCG) on the conformation of interface-adsorbed protein (IAP) and interface-unadsorbed protein (IUAP) and rheological properties of rice bran protein-soybean protein isolate conjugates emulsions were investigated. The results showed that the viscosity, storage modulus, and loss modulus of conjugates emulsions initially increased, and subsequently declined as EGCG concentration increased (0 %–20 %), and reached the maximum value at an EGCG concentration of 10 %. Meanwhile, the absolute value of ζ-potential (−49.333 mV), average particle size (831.033 nm), and flexibility (0.052) of IAP reached the maximum at 10 % of EGCG. The absolute value of ζ-potential and surface hydrophobicity of IAP were higher than those of IUAP. Overall, moderate concentration of EGCG (10 %) enhanced the adsorption of highly flexible and highly surface-charged IAP at the oil-water interface and promoted the formation of a highly viscoelastic interfacial membrane, which improved the rheological properties of conjugates emulsions.

Keywords

• Rice bran protein
• Epigallocatechin-3-gallate
• Soybean protein isolate
• Interface protein structure
• Rheological properties