In this study, a magnetic molecularly imprinted polymers (MIPs) was successfully synthesized by surface imprinting technology for the specific recognition of wheat gliadin (GLI). MIPs showed an obvious hierarchical characteristic by investigations of micromorphology, the magnetic Fe3O4 core were wrapped with SiO2 layer (approximately 40 nm) and imprinted layer (approximately 10 nm). The results of vibrating sample magnetometer (VSM) proved the superparamagnetism of MIPs, which was contributed to the rapid magnetic separation. Furthermore, MIPs displayed excellent selective adsorption ability for GLI through adsorption kinetic model, adsorption isotherm model and adsorption selectivity experiment. The saturated adsorption capacity of MIPs to GLI was 73.55 mg/g under the optimized conditions and the imprinting factor was 3.10. The high performance liquid chromatography (HPLC) manifested that the MIPs were successfully applied to separate template GLI from gluten, reflecting the excellent adsorption specificity of MIPs. Therefore, this research provided a promising method for rapidly separation and specific adsorption of GLI.(c) 2022 Elsevier B.V. All rights reserved.

The impact of different ultrasonic power on the structure and functional properties of wheat gliadin (WG) and green wheat gliadin (GG) was investigated and compared. Ultrasound had no obvious effect on subunit composition and bands of WG and GG, and there were more small molecular weight bands in GG. The results of Fourier transform-infrared spectroscopy, intrinsic fluorescence spectroscopy, and scanning electron microscopy analyses demonstrated that ultrasonic treatment had a significant effect on the structure of WG and GG, inducing the transformation from order structure to disorder structure. The dispersion and uniformity were better at 400 and 300 W, respectively. Under proper ultrasonic treatment, the particle size of WG and GG was significantly reduced, and the free sulfhydryl groups and surface hydrophobicity were significantly increased (p < 0.05). Furthermore, the functional properties of WG and GG such as solubility, emulsification properties, water holding and oil holding properties, thermal stability, and digestibility were enhanced. The better functional properties of WG and GG were obtained at 400 and 300 W, respectively. These results indicated that ultrasonic treatment with appropriate power was a valuable method for improving functional characteristics of WG and GG. PRACTICAL APPLICATION: Ultrasonic treatment could cause structural changes of wheat gliadin (WG) and green wheat gliadin (GG), and their functional properties are improved under appropriate power. This study compares the effects of ultrasound on WG and GG, and the results will provide theoretical guidance for the development of GG in the food industry.

AbstractIn this study, the in vitro digestion process of green wheat protein (GWP) was explored by simulating the gastrointestinal digestion. The digestibility of GWP was 65.23%, and was mainly digested by trypsin. During the digestion process of GWP, large‐size particles are digested by pepsin, and medium‐sized particles are digested by trypsin into smaller particles; irregular large block structure with smooth surface was gradually turned into smaller blocks with porous surface; and the spatial conformation was loosened mainly by the unfolding of β‐sheet structure. Gel electrophoresis demonstrated that HMW glutenin and ω‐gliadins in GWP were completely digested, while LMW glutenin and α/β/γ‐gliadins were partially digested. Additionally, the peptide lengths were relatively dispersed after pepsin digestion. Most of the peptides (76.5%) fell into the range 3–15 amino acid after pepsin and trypsin digestion. The molecular weight (MW) of most pepsin digestion products was above 2000 Da, whereas the MW of trypsin digestion products was mainly concentrated in 500–2000 Da. Besides, the sensitizing peptide sequence of wheat protein was detected in the final digestion products of GWP. This research provided a theoretical guidance for the development and application of GWP.

This research aims to investigate and compare interaction mechanisms between glutenin (Glu)/gliadin (Gli) and chlorogenic acid (CA)/luteolin (LU) at pH7.0, as well as its impacts on the structure of Glu/Gli and antioxidant activity of CA/LU. CA/LU strongly quenched the fluorescence of Glu/Gli in a static mode, and fluorescence quenching of Glu/Gli by CA was stronger than that of LU. Binding constant (Ka) of CA and Glu was the largest among four mixed systems. The isothermal titration calorimetry also confirmed that Ka were declined in the order of Glu-CA, Gli-CA, Glu-LU and Gli-LU, and the main forces were hydrogen bonding and hydrophobic force. Synchronous fluorescence demonstrated the interaction sites of CA/LU with Glu/Gli were close to Tyr and Trp residues, respectively. Three-dimensional fluorescence spectra manifested CA had a greater impact on conformation of Glu/Gli. Meanwhile, secondary structure analysis displayed that CA made the structure of Glu/Gli disordered, whereas LU made the structure of Glu/Gli more compact. Furthermore, CA/LU reduced the surface hydrophobicity of Glu/Gli. This interaction displayed a synergistic antioxidant effect, and the synergistic effect was stronger in CA-Glu and CA-Gli. Therefore, these findings suggest that interaction mechanisms and the effect of CA/LU on structure of Glu/Gli are significant different.