Study On Extraction Technology Of Flavone And Pectin Polysaccharide From Okra And Its Application In Fruit Preservation

In order to improve the utilization value of okra,the thesis takes okra as raw material to explore the ultrasonic extraction technology of Flavonoid from okra,the preparation technology and properties of the gum polysaccharide,the preparation and rheological properties of the film coating agent,And the application in Cherry fresh keeping.The results are as follows:1.The single factor experiment and response surface methodology were used to optimize the extraction process of Flavonoids from okra.The results showed that the optimum conditions were as follows:the ratio of material to liquid was 1:27,the concentration of alcohol was 61%,and the ultrasonic time was 21 min.under these conditions,the extraction rate of flavonoids was 10.61 mg/g.In addition,the maximum scavenging rate of okra flavonoids on DPPH free radical was 87.2%,and the IC50 value of half scavenging rate was0.30 mg/ml.the results showed that okra flavonoids had certain scavenging ability on DPPH and antioxidant activity.2.The single factor experiment and response surface method were used to optimize the extraction process of pectin polysaccharide from okra.The optimum conditions were as follows:extraction temperature was 83?,extraction time was 63 min,solid-liquid ratio was1:77,p H=4.Under these conditions,the extraction rate of pectin polysaccharide was 17.75%.The results showed that the content of galactic acid was 40.24±1.37%,ash content is4.72±0.38%,protein content was 4.97±0.16%and degree of esterification 59.73±0.42%?Intrinsic viscosity of pectin polysaccharide.The average value was 44.29 d L/g,and the viscosity average molecular weight was 2.61×10⁶ g/mol.3.The rheological properties of different concentrations of okra pectin polysaccharide solution and okra pectin polysaccharide film were studied:In the concentration range of0.1%-1.5%and the shear rate is 0.01-1000s^-1,the viscosity of the okra pectin polysaccharide solution and the okra pectin polysaccharide coating agent decreases with the increase of the shear rate,which is a non-Newtonian fluid of pseudoplastic fluid.In addition,the viscosity of both of them increased significantly with the increase of the concentration,but at the same concentration,the okra pectin polysaccharide coating agent showed a lower viscosity.Compared with the okra pectin polysaccharide coating agent,the chitosan coating agent has a lower molecular weight and a significantly lower viscosity,which mainly shows a more obvious Newtonian fluid.Frequency scanning experiments show that the okra pectin polysaccharide coating agent exhibits stronger solid elastic characteristics than the okra pectin polysaccharide solution.The experimental results of the temperature ramp oscillation experiment show that in the range of 10?-95?,the modulus of the okra pectin polysaccharide solution and the okra pectin polysaccharide coating agent gradually decreases with the increase of temperature,which is a kind of weak Gel,there is no obvious gel point.4.The results of the study on the preservation effect of okra pectin polysaccharide compound coating agent on the preservation of cherries show that the 0.5%preservation effect is better after the comprehensive influence on the quality of cherries,and the weight loss rate,decay rate,color difference,hardness,vitamin C content,and titratable are slowed down.The acid content and breathing intensity can effectively maintain the quality of cherry.