Extraction,Purification,Identification And Phisicochemical Properties Of Anthocyanins Derived From Color Wheat Bran

Anthocyanins,the word from Greek Anthos（one flower）and Kyanos（blue color）,is one of the most widely distributed pigments in plants.It h as various colors,such as blue,purple,dark red,red and orange.Anthocy anins have a variety of physiological activities,such as antioxidant,anti-in flammatory,anti-tumor and cardiovascular protection.It has become an im portant food functional ingredient.Color wheat（CW）is a valuable wheat g ermplasm resource.Because its bran is rich in anthocyanins,the seeds app ear purple,blue,brown and black and other color grains,which has been highly valued by wheat breeders in the world.In order to improve the ai m of breeding,and develope and utilize the anthocyanins in cereals,an ex periment was conducted.In this paper,the different color wheat brans（CW B）were used as raw material.The technologies of extraction and purificat ion of color wheat Bran Anthocyanins（CWBA）were optimized.And the c omponents of anthocyanin in different varieties were qualitatively identified and quantitatively analyzed.At the same time,the stability of anthocyani ns and its antioxidant activities in vitro were studied.The contents and re sults of the research were as following.Firstly,the anthocyanins from black-wheat 76（H76）bran were extracte d by acidi fied alcohol in the present work.And the effects of pH,alcoh ol concentration,extraction temperature,extraction time,ratio of liquid to materialand extraction times were studied.The anthocyanins extracting con ditions were optimized by theorthogonal experiment based on the single fa ctor tests.The result showed that the obtained optimal extraction condition s were p H 1.0,concentration of ethanol 60%,temperature 70℃,extraction time 90 min,and ratio of liquid to material 20:1（mL/g）.Under the condi tions,the yield of anthocyanins extraction is 48 mg/100g.The most signif icantly affecting factor was the concentration of ethanol followed by extrac tion temperature.But the influences of extraction time and liquid ratio on extraction of wheat bran anthocyanins were not significant.Secondly,the macroporous resin was used to carry out static adsorpti on and desorption of CWBA,and the adsorption and desorption conditions were optimized.The adsorption and desorption effects of XDA-7 in thefive kinds of macroporous resins（D101,LSA-800B,XDA-7,AB-8 andNKA-9）were the best,Q2>H76>Z1>LHD.Macroporous resin static adsorp tion and desorption equilibrium time were 24 h,10 h.The pH of the sam ple solution was 1.0.Sample concentration was 3mg/mL.The eluent was80%aqueous ethanol.After purification,the color value of Z1,Q2,H76,LHD increased 6.39,6.64,6.40,6.58 times respectively.Thirdly,four kinds CWBA were analyzed qualitatively and quantitativ ely by combination of ultraperformance liquid chromatography-photodiode array（UPLC-PDA）,quadrupole-time-of-flight mass spectrometry（QTOF-MS）,and tandem mass spectrometry（MS/MS）.Z1,Q2,H76 and LHD contained15,13,16 and 17 anthocyanins respectively.The major anthocyanins were cyanidin and peonidin anthocyanin.Z1 has the highest content,LHD has t hemost species.Among them,cyanidin-3-glucoside,cyanidin-3-rutinoside,p eonidin-3-rutinoside-5-glucoside,peonidin-3-rutinoside and malvidin-3-rutinos ide were all found in 4 varieties.Only Q2 and H76 contain petunidin deri vatives,only LHD contains delphinidin derivatives,Q2 does not contain m alvidin derivatives.In the present research,eleven anthocyanins were partia lly identified for the first time in the four color wheat bran.The quantific ation ofanthocyanins in wheat bran wascarried out using cyanidin-3-glucosi de as standard.The order of anthocyanins content was Z1>LHD>H76>Q2.The content of cyanidin-3-hexanoside in all the detected anthocyanins was the highest.It was 64.70,43.57,60.03 and 60.72 mg/100g in wheat Z1,Q2,H76 and LHD,respectively.Z1,Q2,H76,LHD acylated anthocyanins content was less than non-acylated anthocyanins.Finally,the influences of pH,temperature,light,metal ions and other factors on the stability of CWBA were studied and the antioxidant activiti es of the four kinds of CWBA were evaluated.The results showed that p H had a great effect on CWBA.The higher the temperature,the poorer th e preservative effect of anthocyanins was.The light could affect the stabili ty of CWBA anthocyanins,dark was more conducive to the preservation o f anthocyanins.Therefore,anthocyanins should be kept in the dark at low temperature.After the addition of Fe³⁺and Cu²⁺into CWBA solution,the precipitate appeared immediately and the anthocyanin solution faded,which had the strongest destructive effect on anthocyanins.Ascorbic acid,sodium sulfite and hydrogen peroxide destroyed the stability of CWBA.The type and content of anthocyanins had an impact on the antioxidant capacity of CWBA.The order of capacity of CWBA extract scavenging DPPH freerad ical was Trolox>Z1>H76>Q2>LHD.The order of ability of CWBA extract to scavenge ABTS free radicals was Trolox>H76>Z1>Q2>LHD.The order of reducibility of iron in CWBA extract was Z1>H76>Q2>LHD.