Research On The Extraction Of Nobiletin And Compound Preservative Application

Citrus is one kind of plants of Rutaceae,which cultivated all over the world,but China is the origin center in the world,also the world's citrus producing countries.It is widely distributed in Hunan,Guangxi,Sichuan and other places,has got the first output 2500 million tons production in the world.Whatever processing or fresh of Citrus will produce a large number of skin,accounting for about 30%of the total amount of citrus.If it was used unreasonable,will cause a waste of resources or environmental pollution.Therefore,make full use of natural nobiletin in waste orange and citrus peel,will bring huge economic benefits for the comprehensive utilization of citrus.In this study,Sichuan Meishan citrus was the main raw materials,nobiletin was extracted by the methed of double enzymatic extraction,and design analysis method to determine the best extraction response condition,then the nobiletin was used in systematic research to study its antibacterial properties and preservative on green peppers,the main research contents and conclusions are as follows.(1)Combined the cellulose and pectin compound enzyme pretreatment with leaching extraction technology extracted nobiletin from the citrus peel,compared with the nobiletin extracted by traditional process,citrus nobiletin leaching rate increased significantly in the former.Based on the single factor experiment,explore effects of the proportion about cellulase and pectinase compound,the addition quantity compound enzyme,the volume fraction of ethanol,the temperature of water bath,the time of hydrolysis and the solid-liquid ratio on nobiletin yield,and design the response surface analysis method.After the response surface analysis,we got the optimum technological conditions,the proportion of cellulase and pectinase was 1.5:1,the dosage of compound enzyme was 5%,the volume fraction of ethanol was 70%,the temperature of water bath was 61?,the time of enzymolysis was 2 h,the solid-liquid ratio was 1:15,the nobiletin yield was 265.1 ?g/g,compared with the single factor experiment,the best yield increased to 5%.(2)The antibacterial test showed that nobiletin have inhibitory effect on 3 kinds of common fruits and vegetables pathogenic bacteria.In PDA liquid medium,nobiletin with concentration of 20 mg/L can effectively inhibit the growth of cucumber fusarium,penicillium,yellow tail 3 kinds common fruits and vegetables pathogenic bacteria.Minimum Inhibitory Concentration to determine the minimum nobiletin concentration for 3 kinds of pathogenic bacteria,the minimum bacteriostasis,the minimum bacteriostasis concentrations for cucumber fusarium is 8 mg/L,for penicillium is 2 mg/L,for yellow tail bacteria is 8 mg/L.Provide theoretical basis for the application of nobiletin.(3)With green pepper as the research object,using the three factors and three levels orthogonal experiment to explore the effects of the complex of nobiletin,chitosan,sodium alginate on preservation of green peppers,and with Vc content as control index,selected the best formula of the compound fresh-keeping agent are as follows:nobiletin is 0.006%,chitosan is 0.4%,sodium alginate is 0.2%.After the treatment,green pepper kept goods value during 48 days storage under the temperature of(9±1)?,the shelflife was prolonged.