title: Binding, stability, and antioxidant activity of quercetin with soy protein isolate particles.
abstract: This work is to study the potential of particles fabricated from soy protein isolate (SPI) as a protective carrier for quercetin. When the concentration of SPI particles increases from 0 to 0.35 g/L, quercetin gives a gradually increased fluorescence intensity and fluorescence anisotropy. The addition of quercetin can highly quench the intrinsic fluorescence of SPI particles. These results are explained in terms of the binding of quercetin to the hydrophobic pockets of SPI particles mainly through the hydrophobic force together with the hydrogen bonding. The small difference in the binding constants at 25 and 40 °C suggests the structural stability of SPI particles. The relative changes in values of Gibbs energy, enthalpy, and entropy indicate that the binding of quercetin with SPI particles is spontaneous and hydrophobic interaction is the major force. Furthermore, SPI particles are superior to native SPI for improving the stability and radical scavenging activity of quercetin.
authors.affiliation: School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Yufang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: xiaoyong@ecust.edu.cn.
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Wang
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D005453:Fluorescence; D010084:Oxidation-Reduction; D011794:Quercetin / Q000737:chemistry*; D030262:Soybean Proteins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D000975:Antioxidants; D030262:Soybean Proteins; D011794:Quercetin
keywords: Antioxidant; Fluorescence; Quercetin; Soy protein isolate; Stability