| Dioscorea alata, lianas of Dioscorea, purple yam have a long historical standing was Planted in hainan province. Purple ones indicate that contain certain pigments,belonging to anthocyanin. Anthocyanin is an edible natural pigment,a kind of flavanoid compound.At present,few researches have been done on the pigment of purple Dioscorea alata.The study has made an initial exploration into the separation and extraction and analysis of the pigment in purple Dioscorea alata which from Research Center of Hainan University, College of Agriculture yam, and the stability and the biological activity of extracorporeal anti-oxidation have also been studied.Main finding as follow:1、Study on Ultrasonic-assisted Extraction of anthocyanin from purple Dioscorea alataUltrasonic-assisted extraction technology was used to extract anthocyanin.Based on the single-factor experiments, solvent-material ratio, extraction time, ultrasonic frequency and extraction temperature as test factors. The result showed that the optimum extration condition was obtained as follows:ratio of liquid to solid36mL/g,extraction time122S,ultrasonic frequency63%,extraction temperature37℃.Under the optimum condition, the anthocyanin yield was76.35%.2、Study on Ultrasonic/microwave-assisted Extraction (UMAE) of anthocyanin from purple Dioscorea alataUltrasonic/microwave assisted extraction technology was used to extract anthocyanins, the optimum conditions were determined through Box-Benhnken center-united experiment design. Time and temperature were used two models. Based on the single-factor experiments, the extraction yield of anthocyanins as the response value, a3-factor,3-level Box-Behnken experimental design was applied. The result showed that the optimum extraction condition was obtained as follows:on the temperature mode:ratio of liquid to solid48mL/g,extraction time283s, extraction temperature46℃.Under the optimum condition, the anthocyanins yield was79.38%, Higher than10.63%of time mode.3、Study on Purification technology of anthocyanin from purple Dioscorea alataCrude extracts using AB-8macroporous resin purification. The result showed that the optimum condition was obtained as follows:pH value of ratio of liquid to solid3.4, adsorption temperature25℃, the optimum eluting solvent:desorption ethanol concentration was40%.After using5times AB-8, circulation operational performance of macro-porous resin AB-8was better.we can get purple pigment of higher purity.The purification rate was85.00%.4、The analysis of Component from purple Dioscorea alataThe spectral analysis of HPLC-MS/Ms for anthocyanin from purple Dioscorea alata showed that three main anthocyanins could be deduced,Including: peonidin-3-xyloserhamnoside Cyanidin-3-(caffeoyl)(sinapoyl)-diglucoside-5-(sinapoyl)-glucoside、 Cyanidin-3-(sinapoyl)-diglucoside-5-(sinapoyl)-glucoside.5、Study on stability of anthocyanin from purple Dioscorea alataThe result showed that the pigment had better stability to be kept in low pH value than in high、pH vaiue, in heat treatmenting after12hours showed instability, but the pigment is suitable for evades the light; Metal ions had little influence to this anthoeyanins pigment within the selected range, among them:Fe3+、Fe2+、Mg2+、Cu2+、k+have a bad influence for the absorbance, Al3+deeped the color; Food additivead had little influence to this anthoeyanins pigment within the selected range、Sucrose, sodium benzoate、sodium sorbate have no harmful effects on the pigment、Monosodium Glutamate、Gum arabic deeped the color.6、Study on analysis of physicochemical of anthocyanin from purple Dioscorea alataAnthocyanin was purified from Crude extracts that from purple Dioscorea alata ination abilities of DPPH radical scavenging activity,as well as the ability to reducing power and ABTS radical scavenging assay were studied in vitro. These results of experiment showed that the purify extract of anthocyanin from purple Dioscorea alata had high antioxidant activities,and higher the Antioxidation of Ascorbic acid.The antioxidant activity of the purify extract of anthocyanin from purple Dioscorea alata, became stronger with the increasing of concentration.Innovation:Ultrasonic-assisted Extraction and Ultrasonic/microwave-assisted Extraction was used optimize the process of anthocyanin from purple Dioscorea alata for the first time; This research was supported by Doctoral Program of Higher Education Research Fund (N0.20080565000); Protection Tropical Crop Germplasm Resources project of Department of Agriculture(No.10RZZY-33); The Cultivation Item of Innovation Talents for "211Project"Construction of Hainan University... |
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