Study On Electrical Properties Of Gelatinized Rice Flour Dispersions Based On Platinum Electrode

Rice is the most important food source to support the living problem of more than one billion people in China,which has been the keen research topic of a lot of scholars.Research on the sensory quality,appearance quality,processing and storage quality of rice has been very extensive,but there is little research on the electrochemical properties of rice.In this paper,the electrochemical oxidation of gelatinized rice flour dispersions was studied by comparing the electrochemical properties of gelatinized rice flour dispersions and gelatinized rice flour dispersions which is degreased and deproteinized.It was hoped that the electrochemical oxidation properties of gelatinized rice can provide a new means of classification.In this paper,graphene-modified platinum electrode was prepared and its application feasibility in exploring the electrochemical properties of gelatinized rice flour dispersions was evaluated.The main contents and conclusions are as follows:(1)Study on the electrical properties of gelatinized rice flour dispersions based on AC Impedance method.AC impedance test of the electrical properties of gelatinized rice flour.The gelatinized rice flour dispersion system has a diffusion effect,and there is a time constant controlled by charge transfer in the high frequency region.The off-sample and un-deprived gelatinization systems follow the same charge transfer mechanism,the charge transfer mechanism involves two effects of capacitance and resistance.The total impedance of the system under test is composed of the solution body impedance and the electric double layer capacitance parallel model,and the system exists solution resistance.Equivalent circuit simulation analysis.The equivalent circuit model of charge transfer resistance and CPE element is selected and then connected with solution resistance.The results show that the factors that cause the higher impedance are the relative content of the amylose and amylopectin,and the amylose is easy to dissolve in the gelatinization process.Therefore,the reaction process is most concholled by the insoluble the height branched amylopectin molecules.The ?2test of the simulated parameters had no significant difference with the actual results at the 5% significance level.The simulation parameters were between 0.44% and 3.50%,so the fitting effect was good.The equivalent circuit model was suitable in the gelatinized rice flour dispersion system.(2)Study on the electrical properties of gelatinized rice flour dispersions based on cyclic voltammetry.Cyclic voltammetric test of the electrical properties of gelatinized rice flour.Gelatinized rice flour dispersions' electrochemical oxidation and reduction process includs three peaks,the two samples followed the same electrical oxidation process,and the oxidation mechanism is consistent with the oxidation of glucose,which are divided into hydrogen,double layer and oxygen area.However,for the gelatinized rice flour dispersion,the first oxidation peak is mainly caused by macromolecular amylopectin,and the second oxidation peak is mainly caused by amylose of small molecules,the electrooxidation of gelatinized rice flour dispersion system is an irreversible process.In the gelatinization time test,the linear equation of the absolute value of the peak current of the oxidation peak I with the gelation time are as follows:xy(10)-(28)95.105.0,997.02R(28).The current of the oxidation peak I tends to decrease with the increase of the gelatinization time.And the oxidation peak I peak has a potential of the negative movement.In the gelatinization concentration test: oxidation,reduction peak potential has the positive movement with the increase in gelatinization concentration,oxidation peak I current with gelatinization concentration's linear equation is: xy-(28)0006.023.0,960.02R(28);The linear equation reduction peak II with gelatinization concentration is:xy(10)(28)15.324.0,962.02R(28),the oxidation peak and the reduction peak current show a significant growth trend with the increase of the concentration.In the scanning rate test,the linear equation of the reduction peak I current with the scanning rate is: xy(10)(28)15.324.0,962.02R(28).There is a significant positive correlation between the reduction peak current and the scan rate,indicating that the electrode reaction is a surface control process and diffusion control.There is a transport limit,gelatinization system on the role of the charge is very strong.In the scanning cycle test,the linear equation of the peak II current and the scanning rate is:the oxidation peak current has been basically stabilized after the second cycle,and the peak potential is slightly shifted to the positive direction.The change of the peak current in the cycle is not obvious.The oxidation peak current is The change of the reduction peak current confirms that the electrooxidation of the gelatinization system is an irreversible process.(3)Identification of rice samples based on starch content and electrical properties.Analysis of rice based on starch content.According to the amylose and amylopectin content,the rice samples were divided into three groups.Rice Fisher discrimination based on electrochemical parameters.According to theresults of starch content clustering,the rice samples were divided into three groups,and the group within the correct rate of 100%,cross validation accuracy rate of 52%.Marsh Fisher discrimination based on Principal Factor Score.Two main factor scores G1,G2 were selected based on factor analysis Fisher discriminant results,the group correct rate is 100%,the accuracy of cross validation is 71.4%.Therefore,the factor analysis method of reducing the electrical parameters can reflect the overall characteristics of the sample,the classification is more efficient and simple,and the result is more accurate(4)Feasibility study on the electrical properties of gelatinized rice flour based on graphene modified platinum electrodePreparation of oxidized gypsum modified electrode.The graphene oxide was prepared by the modified Hummers method,and was modified to the surface of the platinum electrode by cyclic voltammetry.Characterization of modified electrodes.The electrochemical impedance spectroscopy(EIS)and the modified electrode(SEM)in 0.10mol/L KCl solution containing K3[Fe(CN)6]and K4[Fe(CN)6] containing 5.00 mmol/L were used to demonstrate that the graphene oxide successfully modified to the platinum electrode surface,and the impedance is much smaller than the bare platinum electrode.Modified electrode repeatability test.4 standard CV curves were obtained in the gelatinized untreated sample.The standard deviation of the peak current intensity between the oxidation peak I and the reduction peak II is within 5%,it was confirmed that the modified electrode was highly reproducible.