Search

[Display omitted] • The soy protein isolate covalently bound to hydroxytyrosol by alkaline method. • The addition of HT transformed the structure of SPI into a disordered one. • SPI-HT adducts have enhanced emulsifying, foaming and antioxidant properties. • The adducts with different concentrations of HT have different optimal properties. This study investigated the effect of different concentrations of hydroxytyrosol (HT) covalently bound to soy protein isolate (SPI) by the alkaline method on the structure and function of the adducts. The amount of polyphenol bound to SPI first increased to a maximum of 42.83 % ± 1.08 % and then decreased. After the covalent binding of HT to SPI, turbidity and in vitro protein digestibility increased and decreased significantly with increasing concentrations of HT added, respectively, and the structure of SPI was changed. The adducts had a maximum solubility of 52.52 % ± 0.33 %, and their water holding capacity reached a maximum of 8.22 ± 0.11 g/g at a concentration of 50 μmol/g of HT. Covalent modification with HT significantly increased the emulsifying and foaming properties and antioxidant activity of SPI; the DPPH and ABTS radical scavenging rates increased by 296.89 % and 33.80 %, respectively, at a concentration of 70 μmol/g of HT. [ABSTRACT FROM AUTHOR]

The effect of covalent binding of different concentrations of hydroxytyrosol (HT) to soy protein isolate (SPI) by enzymatic method on the structure and function of the complex was investigated. Polyphenol binding rate increased and then decreased with increasing hydroxytyrosol concentration, with a maximum binding rate of 38.10 ± 1.08%. Covalent binding to HT resulted in a significant increase in the turbidity of the adduct and a significant decrease in the free sulfhydryl content and surface hydrophobicity. The structure of the adduct was altered and the α-helix structure was converted to a β-sheet one. The maximum foaming property of the adducts was observed at a HT concentration of 40 μmol/g, which was 28.84% higher than the control SPI. The adduct had maximum solubility (52.84 ± 0.18%) at HT concentration of 50 μmol/g. The emulsifying properties of the adducts were maximized at a hydroxytyrosol concentration of 60 μmol/g. When the HT concentration was 70 μmol/g, the DPPH and ABTS radical scavenging rates of the adducts were increased by 245.03% and 26.35%, respectively, compared with the control SPI. • Soy protein isolate-hydroxytyrosol adducts were prepared by laccase catalysis. • The effect of hydroxytyrosol with different concentrations on SPI structure was studied. • The addition of hydroxytyrosol changed the structure of the adduct. • The adducts have higher antioxidant activity and foaming properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dynamic microfluidic-assisted transglutaminase dual modification of soy protein isolate-chitosan adducts showed significant improvement in their structural and functional properties. • The solubility and the degree of binding of the adducts were significantly increased. • The magnitude of the change in the secondary structure of the protein in the adduct was increased. • The surface hydrophobicity of the adduct was increased and the average particle size was reduced. • After in vitro digestion, the antioxidant activity of the adducts was significantly enhanced. In this study, soy protein isolate (SPI)-chitosan (CS) adducts were prepared by using dynamic microfluidic-assisted transglutaminase (TGase) modification. It was shown that the solubility and degree of binding of SPI-CS adducts prepared by dynamic microfluidic-assisted TGase modification were better. After the samples were treated twice at 400 bar, the degree of binding for SPI-CS adducts increased to 31.97 ± 1.31%, and the solubility increased to 66.25 ± 1.10%. With the increase of microfluidic pressure, the exposed free sulfhydryl groups increased, the particle size reduced, and the surface hydrophobicity first increased and then decreased. Under the action of the pressure generated by microfluidics, the structure of the protein in the SPI-CS adduct was unfolded and transformed from an ordered structure to a disordered one. The SPI-CS adducts prepared with assisted dynamic microfluidic treatment showed significantly higher ABTS radical scavenging rate, DPPH radical scavenging rate and reducing power after in vitro digestion compared with that of SPI-CS adducts prepared with TGase alone. This result indicated that appropriate dynamic microfluidic treatment improved the structural and functional properties of TGase-modified SPI-CS adducts and significantly increased the antioxidant activity after in vitro digestion. [ABSTRACT FROM AUTHOR]

The Maillard reaction involves a series of complex reactions; fluorescent compounds have been considered as vital intermediate products of the reaction. In this article, carbon dots (CDs) based on the Maillard reaction (MR-CDs) were prepared with L-tryptophan and D-glucose, and they had excellent photoluminescence stability. MR-CDs showed stable pH-dependence behavior and exhibited an excellent linear response to pH in the range of 4.0–7.5 and 7.5–13.0, respectively. Under the masking effect of sodium fluoride for Fe(III), MR-CDs showed excellent selectivity and sensitivity for Cr (VI). The linear range of Cr(VI) was 0.2–50 μM and the limit of detection was 20 nM. (S/N ≥ 3). Furthermore, MR-CDs were used to detect Cr(VI) in tap water samples. The recoveries were between 95.8% and 98.94%, and RSDs were less than 3.17%. [ABSTRACT FROM AUTHOR]