Study On Extraction,Purification,Antioxidant Acticity And Stability Of Polyphenols From Black Chokeberry(Aronia Melanocarpa)

Chokeberry(Aronia melanocarpa),fruit contains a lot of polyphenols,is currently the highest content of known plant fruit.However,the study on the extraction and purification of polyphenols is particularly important because of its bitter taste,not easy storage,and limited of producing area.This study selected from Liaoning Haicheng chokeberry frozen fruit as raw material,and the extraction and purification of polyphenols were optimized respectively.At the same time,through the determination of DPPH,ABTS and superoxide anion radical scavenging,to evaluate the antioxidant activity of purified chokeberry polyphenols.Comparing the antioxidant activity of chokeberry,blueberry,raspberry and blue honeysuckle polyphenols by cell antioxidant assay.And the stability of the purified chokeberry polyphenols were determined.The main results are as follows:1.To determine the optimal extraction technology of Polyphenols from chokeberry,and to determine its antioxidant activity.By using the ultrasonic assisted extraction to carry out single-factor experiment of ethanol concentration,liquid ratio,extraction temperature and extraction time,based on the experimental results obtained,RSM(Response Surface Methodology)was used to optimize the process conditions.By determining the scavenging rate of DPPH,ABTS and superoxide anion free radical to evaluate its antioxidant activity of polyphenols.Results show:The optimal conditions of extracting polyphenols from chokeberry were the raw material with a 44-fold volume of 55%ethanol,extraction temperature 45?,extraction time,90 min.The scavenging effect of polyphenols of chokeberry on DPPH,ABTS and superoxide anion was strong,and the scavenging capital was positively related to the mass concentration of polyphenols.The amount of extracted polyphenols of chokeberry was up to 19.549 mg/g on the optimal conditions,and the polyphenols had strong antioxidant capacity.2.In this study,macroporous adsorption resins were used for the purification of polyphenols from chokeberry.The macroporous resin XAD-7 was selected as the most suitable from among six candidates.The best purification parameters optimized by static adsorption and desorption tests,were as follows:adsorption and desorption time were 4 and 2h,respectively,sample concentration of 3.61mg/mL,sample pH of 7,desorption solution of 95%ethanol(pH 7).The best purification parameters optimized by static adsorption and desorption tests,were as follows:sample loading amount of 560 mL,at a flow rate of 2mL/min,a water wash volume of 350 mL.Under these condition,the purity of polyphenols from chokeberry was improved from 11.62%to 64.37%,indicating that macroporous resin XAD-7 has better purification effect for polyphenols from chokeberry.3.In order to further study to purified goods by ABTS and FRAP assays determine antioxidant activity.And on this basis,investigating antioxidant activity of polyphenols from chokeberry,blueberries,haskap berries by HepG2 human liver cancer cells.The results show that polyphenol from chokeberry has a strong antioxidant effect,and can effectively remove ABTS and FRAP radicals.the CAA values of polyphenols from chokeberry slightly lower than blueberry.And the CAA value of polyphenol haskap showed the lowest.The results indicated that compared with other berry polyphenols,chokeberry polyphenols had stronger antioxidant activity.Taking into account the content of polyphenols in fruit,polyphenols from chokeberry are a very valuable natural antioxidant products.4.This research has determined the stability of chokeberry polyphenol on pH,sugar,temperature,light,oxidant and preservative.The polyphenol conservation could be 96.12%on pH 2;Sugar had a positive effect on the stability of polyphenols,and the retention rate was positively correlated with the sugar concentration,but there was no significant difference in the preservation rate of the different sugars;With the increase of light,the retention rate of polyphenols decreased significantly,and polyphenol was the most stable under the dark condition;When the temperature was above 50? the temperature has a significant effect on the retention rate of polyphenols;Reductant-oxidant had a negative effect on polyphenol,and oxidant had more;Preservative can effectively reduce the degradation of polyphenols,but with the increase of the concentration of preservatives,the retention rate of polyphenols was not significantly increased.