The Research On The Effect Of Ozone And Ultraviolet Combined Process On Microbes And Bioactive Compounds Of Dried Lycium Barbarum L.

It is rich in nutritional value of Lycium barbarum L. and the quality directly determines the acceptance in it. Currently the dried Lycium barbarum L fruit (commercially wolfberry) on the market was influenced by the dust, microbial contamination in circulation and dried process.lt affecting the degree of food safety and export seriously. The topic for this problem, This paper commercial Lycium barbarum L. as raw materials, optimization the best sterilization condition of which ozone, ultraviolet and composite processing sterilization by response surface. On this basis,the change of the quality, active ingredients, and antioxidant capacity were analyzed by the best sterilization condition Specific research contents and results are as follows:(1) Ozone and UV combined treatments wolfberry fruit is high in ozone, ultraviolet sterilization single sterilization rate.To optimize the optimal conditions for ozone and ultraviolet germicidal effect of combined treatment wolfberry by response surface analysis software is:relative humidity of 90% + 5%, irradiation distance of 31 cm, the processing time was 32 min, the ozone concentration was 31 mg/m3, in this condition the actual measured ozone UV germicidal compound was 98.99%; UV combined treatment with ozone and untreated wolfberry wolfberry compared microbiological indicators have reached in the national standard range, the color parameters L*, a* value increased significantly, b* value, ash content decreased, the rest of the physical and chemical showed no significant change, the ozone and UV combined treatment wolfberry both reached bactericidal effect, but also enhance the appearance quality of Lycium barbarum L. The quality of Lycium barbarum L. dry fruit did not change significantly after treatment under optimum conditions. The seventy-eight volatile components were identified from Lycium barbarum L. with different processing methods.including 18 kinds of esters,21 kinds of alcohols,16 kinds of olefins,15 kinds of ketones,5 kinds of aldehydes,3 kinds of acids,4 kinds of ethers and HCAS. PCA analysis identified 42 main volatile components. Combining with clustering analysis comprehensive evaluation that the flavor of volatile components descending order was after of combined treatment of Ozone and UV drying Lycium barbarum L> after of combined treatment of Ozone and UV and vacuum dried Lycium barbarum L> dried Lycium barbarum L.>fresh Lycium barbarum L..(2) The sixty-eight volatile components were identified from before and after the combined treatment of ozone and ultraviolet Lycium barbarum L. PCA analysis identified 35 main volatile components. Low field NMR studies drawn relative content of different treatments wolfberry fruit three states of water,in which Lycium barbarum L.by Ozone and UV combined treatment consisting of water, half-bound water, combined with the relative water content is lower than that of untreated Lycium barbarum L; from microstructure seen the internal organization complex junction was fluffy soft spongy tissue thin, loose structure, better quality in Lycium barbarum L. The moisture equilibrium moisture content of Lycium barbarum L with increasing water activity value big increases and the Lycium barbarum L by ozone and ultraviolet composite fruit was lower than untreated.(3) The results showed that there were significant difference(p<0.05) between the contents of flavonoids, carotenoids in Lycium barbarum L. processed by vacuum drying, drying after combined treatment of ozone and ultraviolet, but the impact on the polysaccharide content is not significant. The flavonoid content and antioxidant activity was highest of which ozone and ultraviolet combined treatment vacuum dried Lycium barbarum L. The antioxidant capacity of extract and flavonoids, rutin, ferulic acid content was significantly positively correlated,but polysaccharides, lutein content was not significant; the degree regression models between three antioxidant ability indicates and the content of flavonoids, carotenoids, β-carotene, caffeic acid, ferulic acid fitted better and significantly.