Study On The Synergistic Degradation Of Auricularia Auricula Polysaccharide By Microwave And Hydrogen Peroxide And Its Antioxidant Activity And Rheological Properties

Because of its high molecular weight,high viscosity and poor water solubility,natural Auricularia auricula polysaccharides are not conducive to bioabsorption into the body to play its functional activities,which seriously restricts the further application of Auricularia auricula polysaccharides.The results show that the preparation of low molecular weight polysaccharides by degradation treatment can solve the above problems.Microwave is an efficient processing technology,which can improve selectivity,reaction speed and product yield.As an efficient and clean oxidant,H2O2 is often used to synergize degradation with physical technology.Research has proved that H2O2 has a significant promoting effect on degradation.In this paper,microwave and hydrogen peroxide synergistic degradation technology was used to study the degradation process of Auricularia auricula polysaccharides,and the effects of degradation treatment on the antioxidant activity and rheological properties of Auricularia auricula polysaccharides were analyzed,which provided experimental basis for the preparation of oligomeric Auricularia auricula polysaccharides by microwave and hydrogen peroxide synergistic technology.(1)Microwave power,treatment time,concentration of hydrogen peroxide and concentration of polysaccharide were taken as factors to study the degradation process.Response surface model was used to design the optimal degradation process conditions.The results showed that the concentration of hydrogen peroxide,treatment time and microwave power were positively correlated with the degradation effect,while the concentration of polysaccharide was negatively correlated with the degradation effect.The optimum degradation conditions were as follows: the concentration of hydrogen peroxide was 2.0%,the treatment time was 18 min,the microwave power was 700 W,and the degradation rate of polysaccharides reached91.09%.(2)The degradation products of Auricularia auricula polysaccharides were prepared under the conditions of different concentration of hydrogen peroxide,microwave power and treatment time,and the antioxidant ability of the degradation products of Auricularia auricula polysaccharides was studied.The results showed that when the treatment time was 18 min,the concentration of hydrogen peroxide was2.0%,and the microwave power was 700 W,the scavenging ability of DPPH free radicals of the degradation products of Auricularia auricula polysaccharide was51.02%,29.58% higher than that of Auricularia auricula polysaccharide,the absorbance value of reduction ability was 0.68,0.44 higher,and the scavengingability of hydroxyl free radicals was 67%,47% higher.The effects of concentration of hydrogen peroxide,microwave power and treatment time on antioxidant capacity of Auricularia auricula polysaccharides were positively correlated.(3)The degradation products of Auricularia auricula polysaccharides were prepared under different concentration of hydrogen peroxide,microwave power and treatment time.The effects of degradation conditions on the steady-state rheological properties of Auricularia auricula polysaccharides were analyzed.The results showed that the aqueous solution of Auricularia auricula polysaccharides exhibited typical non-Newtonian pseudoplastic fluid characteristics.The degradation reduced the apparent viscosity of Auricularia auricula polysaccharides.With the increase of treatment time,microwave power and concentration of hydrogen peroxide,the apparent viscosity decreased,and with the increase of shear rate,the phenomenon of shear dilution became more obvious,and the maximum change of apparent viscosity was 18 minutes.The microwave power is 700 W and the concentration of hydrogen peroxide is 2.0%.(4)The degradation products of Auricularia auricula polysaccharides were prepared under different concentration of hydrogen peroxide,microwave power and treatment time.The effects of degradation conditions on the dynamic rheological properties of Auricularia auricula polysaccharides were analyzed.The results show that after degradation treatment,G′ increases with the increase of angular frequency,and the trend slows down gradually,and the elasticity of solution decreases;G″increases with the increase of angular frequency,and the trend slows down gradually,and the viscosity of solution decreases;with the increase of angular frequency,the tan value tends to tanδ<1.The degradation of Auricularia auricula polysaccharide changed from elastic gel to dilute solution,and the change trend was highly correlated with treatment time,microwave power and H2O2 concentration.