Extraction,Separation And Purification,Compound Analysis And Antioxidant Activity Of Red Raspberry Polyphenols

Red raspberry fruits are rich in polyphenols components which are closely related with their medicinal values and health-promoting value.In this study,we have researched the optimized extraction conditions,the optimized separation and purification conditions and analyzed the composition of red raspberry polyphenols from two varatiies:the Fertod Zamatos and U.S.Raspberry.And its radical scavenging activities and anti-lipid peroxidation were also had been studied.There are some major conclusions from this research work as follows:The single-factors tests and L₉?3⁴?orthogonal test were conducted to optimize the better conditions for extracting polyphenols from red raspberry,and the Duncan's Mutiple-Range test was chosen to examine the significant differences among each treatment.The results showed that the optimal extraction conditions for polyphenols were as following:70%?V/V??p H=6?ethanol concentration,extraction temperature at 45?,ratio of material to solvent for 1:6?g/mL?,extraction time for 3.5 h and extraction times for 2 for Fertod Zamatos;and 65%?pH=6?ethanol concentration,extraction temperature at 45?,ratio of material to solvent for 1:5?g/mL?,extraction time for 3.5 h and extraction times for 2 for U.S.Raspberry.Under such conditions,the contents of polyphenols from two kinds of red raspberry were?373.78±4.08?mg/100 g and?287.08±4.91?mg/100 g,respectively.The results indicated that the extraction technology was reliable,stable and practical.Then six variaties of macroporous resins were selected to study their effects of absorptions and desorptions on two kinds of red raspberry polyphenols.The results showed that the X-5 macroporous resin was the most suitable one to separate and purify the red raspberry polyphenols,and the optimized conditions were as following:as for Fertod Zamatos,ratio of diameter to height for 1:14,polyphenol concentrations for 1.4 mg/mL,the volume of polyphenol for 100 mL and the value of polyphenol pH for 3,under which condition the absorption rate was?95.76±2.47?%and the absorption quantity was?9.47±0.94?mg/g.Then when the absorpted polyphenols reaching the adsorption equilibrium point,500 mL distilled water was used to remove the impurities and after then 200 mL 70%ethanol-aqueous solution?pH=6?was choosen to desorpte the absorpted polyphenols at the flow rate for 1.0 BV/h.In such condition,the desorption rate and recovery rate could be up to?91.38±3.03?%and?87.76±1.13?%,respectively.As for U.S.Raspberry,ratio of diameter to height for 1:14,polyphenol concentrations for 1.4 mg/mL,the volume of polyphenol for 100 mL and the value of polyphenol p H for 4,under which condition the absorption rate was?93.37±2.04?%and the absorption quantity was?8.63±1.48?mg/g.Then when the absorpted polyphenols reaching the adsorption equilibrium point,500 mL distilled water was used to remove the impurities and after then 200 mL 70%ethanol-aqueous solution?pH=6?was choosen to desorpte the absorpted polyphenols at the flow rate for 1.0 BV/h.In such condition,the desorption rate and recovery rate could be up to?93.91±1.88?%and?90.16±2.38?%,respectively.The X-5macroporous resin could effectively separate and pufify the red raspberry polyphenols under the optimized conditions,under which the purity of polyphenols could increase from?3.94±0.28?%to?35.79±2.17?%for Fertod Zamato,and from?2.44±0.072?%to?26.43±0.67?%for U.S.Raspberry.Then the results of Ultraviolet Absorption Spectrum?UVAS?showed that there were characteristic absorption peaks of flavonoids and anthocyanins near 200³00 nm and of anthocyanins near 500⁶00 nm for both two variaties of red raspberry polyphenols.So flavonoids and flavonoids might be concluded in red raspberry polyphenols.The results of Fourier Infrared Spectroscopy?FTIR?showed that there were C-O stretching absorption peaks of carbohydrates near 3400 cm^-1 and 1300⁹00 cm^-1 for red raspberry polyphenols of both Fertod Zamato and U.S.Raspberry,which also had C?O stretching absorption peaks of flavonoids near 1753 cm^-1.Based on these findings,we concluded that these two variaties of red raspberry polyphenols might contain carbohydrates and flavonoids and that part of these carbohydrates could be removed after being purified by X-5 macroporous resin.The results of High Performance Liquid Chromatography?HPLC?showed that many complicated absorption peaks were checked in HPLC chromatograms for two variaties of red raspberry polyphenols,indicating that red raspberry polyphenols were a mixture of complex composition.Compared with the retention times of standards,red raspberry polyphenols samples might contain proanthocyanidins B₂,tutin,salicylic acid and ellagic acid.Lastly,4 kinds of antioxidant indicators in vitro were applied for studying the radical scavenging activity of red raspberry polyphenols extractions and 3 kinds of purified solutions.The results indicated that two variaties of red raspberry polyphenols extractions and purified solutions had strong total reducing capacities,scavenging capacities against OH·,DPPH·and ABTS+·,but there were some significant difference.Sepecifically,red raspberry polyphenols had the strongest scavenging capacity against DPPH·,followed by ABTS+·,while they had relatively weaker scavenging capacity against OH·.Thses findings showed that red raspberry polyphenols had strong antioxidant activities,and there were some differences between the extractions and purified solutions,but the specific differences could not be describled from current research.In addition,the polyphenols from Fertod Zamato had stronger antioxidant activities than that from U.S.Raspberry.Meanwhile,3 kinds of methods in vitro were employed to study the anti-lipid peroxidation activities of red raspberry polyphenols extractions and the first stage of purified solutions.Results showed that they had certain anti-lipid peroxidation capacities in a certain concentration range,but there were also some differences.The polyphenols from Fertod Zamato had stronger anti-lipid peroxidation activities than that from U.S.Raspberry.And the crude polyphenol extractions of Fertod Zamato had stronger anti-lipid peroxidation activities than purified one.