Preparation Of Wheat Gliadin-polysaccharide Composite Particles And Their Ability To Encapsulate Resveratrol

Wheat gliadin has the characteristics of self-assembly properties and film formation,adhesion and biocompatibility,so it can be used as a carrier to load bioactive molecules.Due to the instability of wheat gliadin nanoparticles by the antisolvent method,the improvement of stability through protein/polysaccharide interaction and the ability to load resveratrol was studied in this paper.Above all,the preparation conditions of wheat gliadin/gum arabic composite particles were determined by turbidity titration curves and phase diagrams,and their stability and interaction forces were investigated;On this basis,resveratrol was successfully loaded meanwhile the resveratrol loaded with gliadin nanoparticles and the effect of composite particles on the encapsulation stability and efficiency of resveratrol was also investigated.Chitosan hydrochloride was added to further improve the redispersion and encapsulation efficiency,and the differences of vitro digestion simulation and anti-oxidation properties of the particles under different wall materials were examined.Finally,the interaction between proteins,polysaccharides,and resveratrol were investigated.First,wheat gliadin nanoparticles were prepared by antisolvent precipitation,and gum arabic was added to improve the stability of the nanoparticles.Effect of pH,gliadin/gum arabic ratio and gliadin concentration on the gliadin/gum arabic particles were studied by turbidimetric measurement.Spinodal lines for the gum arabic/gliadin/solvent system were built under different pH.The influences of gliadin/gum arabic ratio and their concentrations were represented in the diagram,thus the conditions for preparing stable composite were defined.The stability of gum arabic-coated gliadin nanoparticles?Gliadin/gum arabic=1:3?was further studied compared with uncoated gliadin particles.Gum arabic-coated nanoparticles had a relatively good stability at pH 4.0⁷.0 and remained a relatively low particle size with the elevated ionic strengths.They also had good thermal stability at 80?.Moreover,the interactions between gliadin particles and gum arabic under different pH were further investigated.Hydrogen bond was found to be the predominant force at p H 5.0,while hydrophobic force took charge of the formation of complex at pH 7.0.Subsequently,resveratrol was loaded on gliadin/gum arabic nanoparticles,and the effect of gliadin/resveratrol ratio on particle size,zeta potential,and encapsulation efficiency was investigated.It was found that resveratrol loaded with gliadin nanoparticles stabilized by gum arabic had a lower particle size of 243.2 nm,a higher potential of-28.9 mv,and a higher encapsulation efficiency of 60.1%at 1:8 wheat gliadin/resveratrol ratios.Furthermore,the addition of gum arabic could keep resveratrol loaded with gliadin nanoparticles with lower particle size at pH 4.0⁷.0,80? heat treatment,high salt ion concentration,and 14 days?4? or ambient?storage.In addition,compared to unencapsulated resveratrol,encapsulating resveratrol with wheat gliadin increased the retention of resveratrol under ultraviolet light and14 days of storage.The addition of gum arabic could further improve the retention of resveratrol under ultraviolet light while it did not significantly improve the retention of resveratrol under long times of storage.Transmission electron microscopy results showed that gum arabic adsorbed on resveratrol loaded with wheat gliadin nanoparticles thus changing its size and morphology.On the basis of the above achievements,chitosan hydrochloride carried with high positive charge was coated with the surface of nanoparticles successfully.The research showed that when the nanoparticles had a smaller particle size,lower turbidity complied with a large amount of positive charge at 1:2:1 gliadin/gum arabic/chitosan hydrochloride ratio.Moreover,resveratrol loaded with gliadin nanoparticles stabilized by gum arabic and chitosan hydrochloride was more stable at pH 3.0⁷.0 combined with better redispersibility and encapsulation efficiency further increased to 68.2%.The results of vitro digestion simulation showed that the resveratrol in wheat gliadin nanoparticles,wheat gliadin/gum arabic nanoparticles and wheat gliadin/gum arabic/chitosan hydrochloride nanoparticles was released 62.2%,81.9%and 84.4%respectively in simulated gastrointestinal fluids.Furthermore,resveratol loaded with gliadin nanoparticles stabilized by gum arabic/chitosan hydrochloride had stronger Fe³⁺reducing antioxidant power while the sample only coated with gum arabic had stronger DPPH radical scavenging activity.Finally,the results of X-ray diffraction,differential scanning calorimetry and fourier transform infrared spectroscopy indicated that the encapsulation of resveratrol and the addition of polysaccharides could change the crystal form of resveratol and there was a certain hydrogen bond,electrostatic interaction and hydrophobic interaction in the process of loading resveratrol and coated with polysaccharides.