Study On The Effect Of Shielding Agent On The Degradation Products Of Auricularia Auricula Polysaccharide By Plasma

Because of its high molecular weight and high viscosity,Auricularia auricula polysaccharides are often degraded into low molecular weight polysaccharides in order to improve their biological function and utilization.The previous studies of the research group showed that pulsed discharge plasma and H₂O₂synergistic technology had a significant effect on the degradation of Auricularia auricula polysaccharides,and the type and concentration of free radicals in the degradation system were adjusted by adding corresponding free radical shielding agents(tert-butanol(·OH),carbon tetrachloride(·H),p-benzoquinone(·O),sodium dihydrogen phosphate(hydrated electrons)).It can obviously regulate the degradation rate of Auricularia auricula polysaccharides.However,whether the shielding agent has any effect on the molecular structure and conformation of the degradation products has not been studied.In order to further verify the feasibility of adjusting the degradation degree of Auricularia auricula polysaccharides by adding corresponding free radical shielding agents,pulsed discharge plasma and H₂O₂were used as degradation techniques to study the effects of different kinds and concentrations of shielding agents on the rheological properties,structural characterization and molecular conformation of Auricularia auricula polysaccharides degradation.The purpose of this study is to provide a research basis for the controlled degradation of Auricularia auricula polysaccharides by pulse discharge plasma and H₂O₂.The test results are as follows:(1)The degradation products of Auricularia auricula polysaccharides with different kinds and concentrations of shielding agents were prepared,and the effects of shielding agents on the static and dynamic rheological properties of Auricularia auricula polysaccharides degradation products were analyzed.The static rheology shows that the addition of shielding agent does not change the fluid type of the degradation products of Auricularia auricula polysaccharides,which is still a non-Newtonian and pseudoplastic fluid,showing a shear phenomenon,and the apparent viscosity of the degradation products with shielding agent is positively correlated with the concentration of shielding agent.Compared with several shielding agents,it was found that p-benzoquinone had the greatest effect on the apparent viscosity of the degradation products,and the viscosity increased obviously with the increase of concentration.The effects of tert-butanol,carbon tetrachloride and sodium dihydrogen phosphate on the apparent viscosity were less than that of p-benzoquinone,and the influence trend was not significant.The dynamic rheology showed that the addition of shielding agent could change the viscoelasticity of the degradation products of Auricularia auricula polysaccharides,and the viscoelasticity was positively correlated with the concentration of shielding agent.(2)The degradation products of Auricularia auricula polysaccharides with different kinds and concentrations of shielding agents were prepared and determined by UV,IR and X-ray diffraction,and the effect of shielding agents on the structural characterization of the degradation products was analyzed.The results showed that the shielding agent could not destroy the main structure of the degradation products of Auricularia auricula polysaccharides,and the shielding agent could inhibit the destruction of the crystal structure of Auricularia auricula polysaccharides.The inhibitory effect was positively correlated with the concentration of shielding agent,and the inhibitory effect of tert-butanol and carbon tetrachloride was greater than that of sodium dihydrogen phosphate and p-benzoquinone.(3)The degradation products of Auricularia auricula polysaccharides with different kinds and concentrations of shielding agents were prepared,and their particle size,SEM and Congo red tests were carried out,and the effects of shielding agents on the molecular conformation of the degradation products were analyzed.The results showed that the average particle size and dispersion index of polysaccharide solution decreased by degradation,and the decrease was inhibited by the addition of shielding agent,and the inhibitory effect was proportional to the concentration of shielding agent.The inhibitory effect of benzoquinone and carbon tetrachloride was better than that of tert-butanol.The inhibitory effect of sodium dihydrogen phosphate is the weakest.SEM morphology analysis showed that the degradation of Auricularia auricula polysaccharides changed from compact and smooth aggregation state to rough and loose state,while the addition of shielding agent could increase the surface morphology aggregation degree of degraded polysaccharides,which was proportional to the concentration of shielding agent,and the effect of p-benzoquinone on the morphology aggregation degree of degradation products was greater than that of tert-butanol and carbon tetrachloride,and the effect of sodium dihydrogen phosphate was the least.Congo red test showed that the degradation products of Auricularia auricula polysaccharides with four kinds of shielding agents did not have triple helix conformation.From the above conclusions,it can be confirmed that tert-butanol,carbon tetrachloride,sodium dihydrogen phosphate and p-benzoquinone can inhibit the degradation of Auricularia auricula polysaccharides to some extent.It is feasible to adjust the degradation degree of Auricularia auricula polysaccharides by adding free radical shielding agent.Overall,the inhibitory effect of each shielding agent is p-benzoquinone>tert-butyl alcohol?carbon tetrachloride>sodium dihydrogen phosphate.