Isolation Of Anthocyanins From Aronia Melanocarpa Fruits And Their Antioxidant Activity And Digestion In Vitro

The ripe Aronia melanocarpa fruits were chosen as material,studied on the extraction process of anthocyanins,purification process,high purity anthocyanins were obtained from Aronia melanocarpa and identified the anthocyanins.In vitro antioxidant activity were evaluated with the DPPH·radical scavenging,the OH·radical scavenging,total reducing capability?FRAP method?,and the liposome peroxidation.The crude anthocyanins?CA?,purified anthocyanins?OP?,secondary purified anthocyanins?SP?,high purity anthocyanins?solid phase extraction?were tested in vitro digestion,determination of anthocyanins and total polyphenols content.The DPPH·radical scavenging and the liposome peroxidation as indicators were analysied to determine the anthocyanins antioxidant activity before and after the in vitro digestion.Anthocyanins were extracted from Aronia melanocarpa with water,50%¹00%ethanol and 50%¹00%methanol.The results showed that the optimal yield of anthocyanins was with the 80%ethanol.Four single factor experiments were designed for extracting time,solid-liquid ratio,pH and temperature.Basing on the single factor experiments analysis,the mathematical model was established by the Box-Behnken response surface design.The results showed that the optimum extracting conditions were:extracting time 110 min,pH 2,extracting temperature 34?,solid-liquid ratio 1?16.5.Under these conditions anthocyanins yield reached 6.648mg/g.AB-8 was choosed as the optimal resin after the static adsorption and desorption testing.The optimum purification conditions were 2mg/mL of solution concentration,1?25 of diameter to length,2.2BV,pH2 and 80%ethanol with the elution flow rate of 2.0BV/h,the anthocyanins purity increased 11.5 times.10%⁹0%different concentrations of ethanol solution as the eluent,experimental results showed that polyamide as packing,eluent concentration 80%,the anthocyanins purity reached 55.33%.Solid phase extraction with Waters Oasis?MCX cation exchange column,anthocyanins recovery rate reached 95.3%,the purity 92.34%.The structure identification shows Aronia melanocarpa contains fourkindsofanthocyanins:cyanidin-3-galactoside,cyanidin-3-glucoside,cyaniding-3-arabinoside,cyaniding-3-xyloside.Anthocyanins from Aronia melanocarpa in vitro antioxidant activity showed the following general trend,their ability of the DPPH·radical scavenging,the OH·radical scavenging,total reducing capability?FRAP method?:SP>CA>OP>Trolox.For samples of anthocyanins eluted down from the same column packing,their DPPH·radical scavenging,OH·radical scavenging,total reducing capability?FRAP method?showed positive correlation with the purity.The samples of anthocyanins eluted down from the different column packing,their DPPH·radical scavenging,OH·radical scavenging,total reducing capability?FRAP method?showed faint positive correlation but not conspicuous.The liposome peroxidation had the following general trend:CA>SP>OP>Trolox.For samples of anthocyanins eluted down from the same column packing,there was no positive correlation between the purity and the liposome peroxidation.The samples eluted from the polyamide column by 80%ethanol had the strongest the DPPH·radical scavenging,the scavenging rate was 64.77%,the IC₅₀ value was 25.46±0.66?g/mL.The samples eluted from the D101 column by 80%ethanol had the strongest total reducing capability,the content of Fe²⁺was 0.061mmol/L,the IC₅₀ value was0.86±0.031mol/L.The samples eluted from the polyamide column by 80%ethanol had the strongest the OH·radical scavenging,the scavenging rate was 62.76%,the IC₅₀ value was 0.21±0.0195mg/mL.The samples eluted from the polyamide column by 60%ethanol had the strongest the inhibition of liposome peroxidation,the inhibition ratio was 93.29%,the IC₅₀ value was 3.34±0.29?g/mL.In vitro digestion simulation process,after simulates stomach digestion,anthocyanins,total polyphenols content changed little but total polypolyphenolss and anthocyanins lost vast after simulated intestinal digestion.The content of anthocyanins of CA?OP?SP?PA lost 59.28,61.57%,66.03%and 74.33%respectively.The content of total polypolyphenolss of CA?OP?SP?PA lost 32.06%?35.26%?45.93%?70.76%respectively.After the simulation in vitro digestion,the ability of the DPPH·radical scavenging and the inhibition of liposome peroxidation of high purity anthocyanins?PA?almost unchanged,while a large number losses of anthocyanins in intestinal digestion process,but the activity of residual anthocyanins was not affected.After simulates digestion of the stomach,the ability of the DPPH·radical scavenging and the inhibition of liposome peroxidation of CA,OP and SP almost did not changed,decreased significantly after simulated intestinal digestion.