Study On Extraction Technology And Antioxidant Activity Of Persimmon Tannin And Its Application In Supercapacitor

China is one of the original center of persimmon plants and the origin of persimmon,persimmon resources are rich,persimmon cultivation has a long history,cultivated area and yield are always ranked the first in the world.However,the Hand-picked green persimmon produced in order to increase the yield of persimmon during planting accounted for about 20%of the total production,which could not produce economic benefit and caused a lot of waste,while Hand-picked green persimmon was rich in tannin,which was the ideal raw material for the extraction of persimmon tannin.Persimmon tannin is an important natural active substance,which widely exists in persimmon meat,persimmon peel,persimmon stem and persimmon leaf.It has significant antioxidant,radiation resistance and bacteriostatic effects.However,the application and promotion of persimmon tannin still has some problems,such as complicated purification process and failure to meet food and drug safety and quality standards,which limits its high value utilization.Therefore,in this paper,Hand-picked green persimmon was used as raw material to optimize the extraction process of persimmon tannin,and the antioxidant activity of different grades of persimmon tannin was studied by purification,and the Ti₃C₂T_x/PT composite film was prepared by using Ti₃C₂T_x/PT composite film,and its effect on the morphology,structure and electrochemical properties of the composite film was investigated which provided a basis for high-value application of persimmon tannin.The main contents of this paper are as follows:1、The optimal extraction process of tannin from persimmon was found by single factor test,orthogonal test and verification test.Under the premise of ultrasonic power of 300 W and 80%methanol,the optimal extraction conditions were as follows:the weight of cellulose is 0.5 g,solid-liquid ratio is 1:15,concentration of hydrochloric acid is 1%,extraction time is 90min and extraction temperature is 80℃.The total content of phenolic,content of condensed tannin and extraction ratio were 29.13 mg/g,22.33 mg/g and 7.08%,respectively.The range analysis of orthogonal test results showed that the order of influencing tannin yield was extraction time（C）>cellulase content（A）>solid-liquid ratio（B）>extraction temperature（D）>hydrochloric acid concentration（E）.The order of influence on condensed tannin content was extraction time（C）>solid-liquid ratio（B）>cellulase content（A）>extraction temperature（D）>hydrochloric acid concentration（E）.By adding 10 000 U/g cellulase in the extraction process to improve the extraction effect,the persimmon tannin content and yield of the extract were increased by 82.3%and 80.1%,respectively,compared with that without cellulase.2、Using HPD-500 macroporous resin as adsorbent and using different concentrations of methanol as eluent,different fractions of persimmon tannin could be obtained,and the polymerization degree of persimmon tannin increased with the increase of methanol concentration.Tannins of different grades of persimmon exhibited good scavenging ability of free radicals in different antioxidant systems,and showed obvious dose-effect relationship.When the concentration was 500μg/m L,the hydroxyl radical scavenging rates of 20%,40%,60%,80%and anhydrous methanol eluent were 55.84%,48.31%,47.31%,46.97%and 45.36%,respectively.When the concentration was 14μg/m L,the DPPH·scavenging rates of 20%,40%,60%,80%methanol and anhydrous methanol were 55.85%,57.86%,63.24%,62.67%,60.14%,respectively.When the concentration was 80μg/m L,the scavenging rates of 20%,40%,60%,80%methanol and anhydrous methanol on ABTS⁺·were 71.36%,80.96%,72.41%,88.14%,82.67%,respectively.3、Ti₃C₂T_x/PT composite films with different tannin contents of persimmon were prepared by solvent heat treatment,extraction and filtration,and their electrochemical properties and composition were characterized.It was found that the tannin contents of persimmon could effectively enlarge the layer spacing of Ti₃C₂T_xfilm within a certain range.In the application of supercapacitors,it can reduce the migration resistance of ions in electrolyte and improve the electrochemical performance.Among them,the mass specific capacitance of Ti₃C₂T_x/PT_0.01 composite film electrode is up to 448 F g-¹,which is 23.8%higher than that of Ti₃C₂T_x film.