| This work studys on rich resources of Zanthoxylum bungeanum leaves.The flavonoids and phenolic acids in the Zanthoxylum bungeanum leaves are identified.Extracted and separatied.Then we find that vitexin is the main flavonoid ingredient of Zanthoxylum bungeanum leaves,which can act as new plant material sources of vitexin.In order to get better taste quality,more value-added products of RS,another part of the work is to research on microbial translational of stevia glycosides which have the bitter taste.(1).HPLC-MSn are used to separate and identify flavonoids and phenolic acids in the Zanthoxylum bungeanum leaves.Nine kinds of flavonoids were identified and three kinds of phenolic acid composition,respectively are 190.2 mg/g and 7.2 mg/g.The study found that vitexin is the main flavonoids in the Zanthoxylum bungeanum leaves.By comparing the traditional sources of vitexin-vitex negundo,hawthorn,broussonetia papyrifera leaves,finding that vitexin content in the Zanthoxylum bungeanum leaves was highest(14.11 mg/g),is 36 times of broussonetia papyrifera leaves(0.40mg/g),4 times of vitex leaves(3.23mg/g).(2).The optimum extraction condition of vitexin wasobtained by single factor experiments and orthpgonal test.The optimum conditions for extraction were:ethanol concentration 60%,extraction temperature 55?,extraction time 100 min,solid-liquid ratio 1:40(g/mL),and the extraction content was 14.11mg/g while the extraction rate was 87.02%.(3).The separation and purification process of vitexin in the Zanthoxylum bungeanum leaves was investigated.D101 macroporous resin was determined to be suitable separation materials by static adsorption and desorption experiments.30g Zanthoxylum bungeanum leaves were extracted by 60%ethnol and get 330 mL concentrated extraction.The purity of vitexin was 42.3%after primary purification of D101 macroporousresin.Crystallization process with methanol was used to perform secondary purification.Then we get the vitexin whose purity was 88.5%.After recrystallization with methanol,105.8mg vitexin whose purity was 94.51%was geted.(4).The microorganisms Fusarium oxysporum was screened to transfor Stv into RS.Further researches were focused on the factors which influenced the transformation effect:transmation methods,temperature,pH and substrate concentration.The results showed that conversion rate of Stv reached to 98.1%after converted for 21 h by enzyme,from Fusarium oxysporum(cultivated by solid medium).The transformation conditions:steviolglycoside 2%,55?,pH6.0.Macroporous resin LX-T28 was used to separate and purify converted products RS.40%ethanol was used to elute RA,RA/RS in the eluent rose to 11.89 from 1.22.In the sample fluid,separation of the liquid sample in RA is up about 73.40%of the raw material 60%ethanol was used to elute RS,RS/RA in the eluent rose to 7.83 from 0.81.After being concentrated and dired,the purity of RS reached to 69.88%and the recovery rate was 70.13%.(5).?-Galactosidase from Aspergiluss oryzae can convert SS to RS.The enzyme has substrate specificity with no catalytic activity for RA,RC etc.The conversion of Stv of 99.2%and the yield of RS of 82.85 were obtained with reaction conditions of pH4.5,60?,the concentration of Stv 25 mg/mL,adding enzyme quantity 5 KU/gSS for 5 h.RS was purified by macroporous resin LX-T28.91.4%RS purity could be obtained and the recovery was 73.4%.(6).After analyzing the content of steviol glycosiden from different cultivars of stevia rebaudiana.The results showed that cultivar 15 contained highst stevioside of 13.18%,cultivar 28 contained highst RA of 9.24%,cultivar 9 contained highst RD of 1.3%.These provide reference for breeding varieties of stevia and specific raw material supply. |
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