Study On Extraction,Purification And Antioxidant Activity Of Polysaccharides From Flat-European Hybrid Hazelnut

Flat-European hybrid hazelnut is a good cultivar hybridized by European hazelnut and Flat hazelnut that produced from China.It is rich in nutrients,such as proteins,carbohydrates,vitamins,minerals,oil especially unsaturated fatty acid and so on.Different hazelnut has different nutrients,among the common hazelnut,Flat-European hybrid hazelnut has the highest content of polysaccharides comparing with the European hazelnut and Flat hazelnut,which is cultivated in northeastern of our country widely.In order to develop the hazelnut industrialization,the hazelnut products value-added improve by intensive processing becomes an important way.Flat-European hybrid hazelnut was selected as materials,exploring the technique of extraction conditions,purification methods,structural analysis and in vitro antioxidant activity of polysaccharides from Flat-European hybrid hazelnut were studied fundamentally to provide theoretical support and application of hazelnut development.The experiment main contents and results are listed in the following:?1?Optimization of polysaccharides extraction from Flat-European Hybrid Hazelnut.Based on the single-factor experiment,set extraction temperature,time,ultrasonic power,water-to-material ratio as factors and the yields of polysaccharides as index,we optimized the ultrasound-assisted water extraction conditions of polysaccharides from Flat-European Hybrid Hazelnut by Box-Behnken design of response surface methodology.The optimal extraction conditions were obtained as follow:ultrasonic power 144.54W,extraction temperature 71.16?,extraction time 40.90min and water-to-material ratio 26.99:1.Under these conditions,the highest yield of polysaccharides was 11.97%.It also could be obtained that the effect order of four factors to the yields of polysaccharides is extraction temperature>ultrasonic power>water-to-material ratio>extraction time.The conditions of actual was chosed by ultrasonic power 140W,extraction temperature 71?,extraction time 41 min and water-to-material ratio 27:1.The verifying result was 11.83%.?2?Comparing with deproteinization methods of polysaccharides from Flat-European hybrid hazelnut.The rate of protein removal and the loss of polysaccharides were selected as index,comparing with the effect of sevage,trichloroacetic acid?TCA?,papain and papain-sevage,the reasonable method of deproteinization was chosen.The results showed that the best deproteinization methods was papain-sevage,the rate of protein removal was 92.30%,and the loss rate of polysaccharides was 15.40%.The deproteinization rate of papain method was lower than it,it was 91.26%,but the loss rate of polysaccharides was much lower than it,it was only 4.97%.Therefore,from the considering of retenting the polysaccharides,the papain method was chosen as the reasonable method of deproteinization.According to the papain method,based on the single-factor experiment,the best technological parameter we obtained was:the papain dosage was 2.0%,the enzymatic hydrolysis was pH5.0,the hydrolysis temperature was 60 ? the time of enzymatic hydrolysis was 2 hours.The verified experiment results under these conditions were:the rate of protein removal was 90.31%,and loss rate of polysaccharides was 5.66%.?3?Separation,purification and analysis of polysaccharides from Flat-European hybrid hazelnut.Treatment with different eluant,four different elution peaks were obtained by DEAE-52 cellulose after deproteinization.The highest elution peak FEHP1 was collected and then eluanted by distilled water,two peaks FEHP1-1 and FEHP1-2 were gained by Sephadex G-75 gel.Then Polysaccharides power was obtained after concentrated,dialyzed and freeze-dried.Purity identification results showed that FEHP1-1 and FEHP1-2 were the uniform component by ultraviolet spectrum?UV?scanning and Sephadex G-75 gel filtration chromatogram.Infra-red?IR?spectrometry showed that component FEHP1-1 and FEHP1-2 had four typical absorption peaks of polysaccharides and they both had pyranose conformational monosome.Furthermore,according to the results,the Flat-European hybrid hazelnut polysaccharides might be a kind of protein polysaccharides.High performance Liquid Chrmatography?HPLC?results indicated that the relative molecular weight of FEHP1-1 was 51833Da,the relative molecular weight of FEHP1-2 was 49606Da,and the compose of FEHP1-1 was Fru:Glu:Ara=0.24:1:0.57,and the compose of FEHP1-2 was Rha:Man:Glu:Ara=1:0.31:0.27:0.64.?4?The in virto antioxidant activity of polysaccharides from Flat-European hybrid hazelnut.The antioxidant activities in vitro of FEHP1 was measured by total antioxidant capacity?T-AOC?,2,2-Diphenyl-l-pikryl-hydrazyl?DPPH?radical scavenging,·OH inhitbitting and O₂^-·scavenging methods.The results showed that when the concentration of FEHP1 was 16mg/mL,T-AOC was 8.21U/mL,the O₂^-· scavenging was 44.73%,the DPPH radical sacvenging was 87.61%.When the concentration of FEHP1 was lmg/mL,the ·OH inhitbitting was 90.41 U/mL.The inhabited or scavenged of O₂^-·,·OH and DPPH radical were increased with the increasing of polysaccharides concentration.Therefore,it was also showed that Flat-European hybrid hazelnut polysaccharides could protect the organism from some harmful active oxygen radicals and oxidative damage.