The Extraction And Purification Of Black Carrot Pigment And Analysis Of Structural Characterization

Through experiment, the optimum extraction conditions of acid water extraction were obtained. The optimum of acid water extraction were acid water (pH=1), extraction time 1.5 h at 70℃, black carrot: solvent =1:6, and extracted one times.Purify the black carrot pigment: X-5 type macroporous resin was used, when the absorbency of pigment was between1.502×2-3.252, the adsorption current velocity was l-2BV/h, desorbed at 60%-70% ethanol as eluant with desorption current velocity was 0.5-1BV/h. black carrot pigment was greatly refined by macroporousresin, The black carrot pigment powder owned E_1cm^1% =29.3 .Conclusion from the study of stability: The black carrot pigment is stable to heat, suitable for food process and high temperature sterilization. It is also stable to familiar cation, but can be destroyed by Al³⁺,Fe³⁺distinctly. The black carrot pigment should be deal with avoid light for it has no stability on light, as well on oxidant and reducer. The value of pH has great effect on it.Purify the black carrot pigment the second time: D61 type resin was used, after the second purify, black carrot pigment was greatly refined by macroporous resin, Theblack carrot pigment powder owned E_1cm^1% =52.1. Total anthocyanins of black powderis improved from 9.44% to 25.16%.After analyzed by TLC and LC/MS, it was likely to contain cycanidin mainly. The three's place on cycanidin anthoyanins is substituted by glucoside. After analyzed by LC/MS and combined with literature, we can speculate that they were cycanidin-3-glucoside with one molecule cinnamic acid and one molecule ferulic acid.In this paper, the vitro antioxidant activity of the black carrot pigment and the second purified black pigment was studied. Based the scavenging effect of pigment against DPPH-was studied, its scavenging activity against oxygen free radicals(O₂^-·,·OH,H₂O₂) was determined by fluorescent chemiluminescence method and compared with the ascorbic acid. The results showed that remarkable scavenging effects against DPPH·,O₂^-·,·OHand H₂O₂ were detected, and it's especially strong against·OH, even stronger than L-Ascorbic acid's. Furthermore, scavenging activity and anthocyanins concentration showed a position of dose-response relationship.